Visual outcome of Phacoemulsification

SSuuddaanneessee JJoouurrnnaall ooff OOpphhtthhaallmmoollooggyy

July 2009 - Volume 1, Issue 2

49

Sudanese Journal of Ophthalmology

Published by Sudan Eye Centre in collaboration with Sudanese Eye Research Group.

Editor-in-Chief

Dr. Nadir A M Ali

Associate Editor

Dr. Ismail Abdalla Al Fadul

Production Editor

Optom. Khalid Mohamed Ahmed

Editorial Board (National)

Professor A. Salim Al Hakeem

Dr. Abdel Gadir Al Hassan Al Saori

Dr. Abdalla Al Siddig

Dr. Awad Hassan

Dr. Kamal Hashim Binnawi Assoc. Prof. Mahgoub Saleem

Professor Mamoun M. A. Homeida

Professor Osman Bakheet

Assoc. Prof. Samira Mohamed Ibrahim

Editorial Board (International)

Professor Clare Gilbert

Dr. Paul Courtright

Professor Jia-quan Shen

Professor Lina Hao

Professor S C Reddy Dr. Tajunisah Iqbal

Assoc. Prof. Visvaraja Subarayan

Professor Asad Aslam Khan

Dr. Muhammad Zahid Jadoon

Professor Ahmed Abdel-kareem Mohamed El

Massry

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Sudanese Journal of Ophthalmology (SJO) publishes original, peer-reviewed reports of research in

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50 Sudanese Journal of Ophthalmology

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mailto:[email protected]

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Journals

1. Wright KW, Erikscn KJ, Shors TJ et al.

Recording pattern visual evoked potential under

chloralhydrate sedation. Arch Ophthalmol.

1986;104:718-72. List first 3 authors followed

by et al.

2. Carney RJ. Incontinentia pigmenti – A world

statistical analysis. Arch Dermatol.

1976;112:535-542.

Books and Other Monographs 1. Sagerman RH, Alberti WE. Radiotherapy of

intraocular and orbital tumours. 2nd ed. Vol 1.

New York, Springer, 2003:1-295.

2. American Medical Association Department of

Drugs. AMA drug evaluation (3rd ed.).

Littleton, Publishing Sciences Group, 1977.

Chapter in Book:

Weinstein L, Swartz MN. Pathogenic properties of invading micro-organisms. In : Sodeman

WAJr, Sodeman WA (eds). Pathogenic

physiology : mechanisms of disease. Philadelphia,

WB Saunders, 1974 : 457-72.

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Table of Contents

Editorial Can H1N1 virus (Swine flu) affect the eye? 53

Ali NA

Review Article HIV-related eye diseases -Current updates 54

Tajunisah I

Original Articles Sudan test (ST), a design of simple reading chart in Arabic language with predicted 65

magnification for low vision

Ali AB, Elawad ME, Elsheikh EA

Toxic effects of antiglaucoma topical medications on the conjunctiva – a histological study 71

Hayet M, Soraya M, Abdenacer T, Myriam O

Laser-assisted in situ keratomileusis (LASIK) surgery in the management of anisometropic 76

amblyopia in Sudanese Children

Binnawi KH, Ali NA

Visual Outcome of Phacoemulsification in Al Walidain Charity Eye Hospital – 81

The first 120 cases

Ali MA, Binnawi KH, Ali NA

Chemical injuries of the eye – Clinical study of 40 cases 86

Reddy SC, Reddy PR

Case Reports

Unilateral Isolated Ocular Tuberculosis with no systemic involvement 91 Chan UT , Choo MM , Reddy SC

Letter to Editor 95

Sudan Test (ST) for near vision test

Ali AB

Announcements 96

53

EDITORIAL

Can H1N1 virus (Swine flu) affect the eye?

Welcome to the second issue of Sudanese

Journal of Ophthalmology! I am proud to

announce that we are now indexed in

African Index Medicus (AIM/Hinari),1

and our inclusion in African Journals

Online (AJOL) is also in process. We are

aware that indexing is an important issue

for any peer-reviewed journal to ensure

maximum spread. Thus, one of our

priorities is to get the journal indexed in

all relevant indexing bodies.

One of my anxious patients, who had

common cold and red eyes, asked me

„Doctor, Can this be Swine flu? Can the

virus affect my eyes?!‟ In fact, ocular

involvement in human influenza A virus

diseases (e.g. seasonal influenza) is

common but usually limited to mild

conjunctivitis. Avian Influenza virus

(H5N1), was reported to cause

inflammation of the choriocapillaris and

atrophy of the retinal pigment

epithelium.2

The current outbreak of H1N1 influenza

(formerly known as Swine flu) has

caused global terror. This pandemic was

first reported in Mexico in March 2009

with rapid global spread in a geometric

progression.3 In May, 2009 there was

10,243 confirmed cases worldwide,

including 80 deaths, in 41 countries.4

These figures increased to more than

134,500 affected people in more than 100

countries, including more than 800

deaths, by end of July, 2009.5 Sudan

reported its first two cases of the H1N1

flu virus on 16th of July, with no deaths so

far.6

In view of the rapid spread and the

virulence of this new mutation of H1N1

virus, further clinical studies are needed

to determine its behavior in human eyes.

References

1. African index medicus/Hinari website.

Available at http://indexmedicus.afro.who.int/Journals/Index

j.htm (Accessed on 15th July, 2009)

2. Michaelis M, Geiler J, Klassert D, et al.

Infection of human retinal pigment epithelial

cells with influenza A viruses. Invest

Ophthalmol Vis Sci. 2009 Jun 24. [Epub ahead

of print]

3. Center for Infectious disease research and

policy, University of Minnesota.

http://www.cidrap.umn.edu/cidrap/content/influ

enza/swineflu/news/may0109mexico.html (Accessed on 30/7/2009)

4. WHO. Weekly epidemiological record 2009;

84:185–196

5. WHO. Influenza A (H1N1): Special Highlights.

World Health Organization. Available at

http://www.who.int/csr/don/2009_07_27/en/ind

ex.html (Accessed on 30/7/2009)

6. Reuters News agency.

http://www.reuters.com/article/africaCrisis/idU

SHEA670400 (Accessed on 23/7/2009)

Dr. Nadir A M Ali Editor-In-Chief


REVIEW

HIV-related eye diseases - Current updates Tajunisah Begam Iqbal

Dept. of Ophthalmology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia

Correspondence to: Dr. Tajunisah Iqbal, Dept. of Ophthalmology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia, Email: [email protected], Tel. No. +60192189510.

Abstract

This review is to describe the most common HIV-related eye diseases and to summarize current

updates and recent literature regarding the clinical manifestations, ocular complications and the current treatment strategies of the various diseases.

This review was written based on the search of the Medline, using PubMed, specifically for words

that included current updates of HIV-related eye diseases, AIDS, retinal microvasculopathy, herpes

zoster ophthalmicus, molluscum contagiosum, cytomegalovirus retinitis, acute retinal necrosis, opportunistic infections, Kaposi sarcoma, treatment of retinitis and immune recovery uveitis.

Articles were selected based on clinical importance and references of key articles were included.

Non-English abstracts were not included in this review.

Keywords: HIV-related eye diseases; herpes zoster ophthalmicus; cytomegalovirus retinitis;

toxoplasmic retinochoroiditis; Kaposi sarcoma; immune recovery uveitis.

There are estimated 40 million people worldwide living with HIV/AIDS and 90% of

them are living in developing countries,

particularly those in sub-Saharan Africa and Southeast Asia.

1 The incidence rate for new

HIV infections is still highest in the world in

sub-Saharan Africa and the life expectancy in

these countries has decreased as a result of AIDS complications. These complications,

affecting virtually all organ systems, have

been the principal cause of morbidity and mortality in patients with AIDS.

2

The first report of the ocular manifestations

of AIDS has been reported by Holland et al3

in 1982 and since then, it has been

recognized that 70-80% of adult AIDS

patients will experience an ocular

complication at some point in their illness. A broad range of ocular complications can

occur involving the ocular adnexa and orbit,

anterior segment and posterior segment

manifestations. All patients with HIV disease should undergo routine ophthalmologic

examination since some retinal opportunistic

infections may have a rapid and devastating course leading to blindness in these patients.

The pattern of ocular involvement in HIV

infection has changed over the years with the advent of highly active antiretroviral therapy

(HAART) era.4 Previously ocular

opportunistic infections, especially cytomegalovirus (CMV) retinitis, was a

notorious sign of poor survival but with the

increased use of HAART treatment and the improved survival of patients with better

immune system, ocular infections became

more manageable. In general, CD4+ T-

lymphocyte count has been used to predict the onset of certain ocular infections in

patients who are HIV positive (Table 1).

55

Table 1: Ocular complications of HIV infection versus degree of immunodeficiency as indicated by CD4+ Tcell

count.

Patient’s

CD4+ T cell

count

Type of ocular complications

Vascular Infection Tumor

Any Large-vessel vaso-occlusion Disseminated molluscum contagiosum Ocular surface squamous neoplasia

≤500 cells/µ Herpes zoster ophthalmicus Kaposi sarcoma Lymphoma

≤200 cells/µl Ocular tuberculosis Pneumocystosis

≤100 cells/µl HIV retinopathy Toxoplasmic retinitis Progressive outer retinal necrosis Cryptococcal chroiditis

≤ 50 cells/µl CMV retinitis

CLINICAL PRESENTATIONS

Orbital and adnexal manifestations

Orbital manifestations of HIV infection are not seen very often and some reported cases

include orbital cellulites and primary non-

Hodgkin‟s lymphoma.5 The more common

ocular adnexa lesions in patients who are HIV positive include herpes zoster

ophthalmicus (HZO), Kaposi sarcoma,

molluscum contagiosum and ocular surface squamous neoplasia.

Herpes Zoster Ophthalmicus (HZO)

Herpes zoster ophthalmicus (HZO) is a

painful vesicular dermatitis over the

forehead, which results from the reactivation of latent varicella zoster virus in the

ophthalmic division of the trigeminal nerve

(Figure 1). When the nasociliary branch of the ophthalmic division is affected, the

patients may present with vesicles at the tip

of the nose, known as Hutchinson‟s sign. This sign indicates presence of ophthalmic

involvement in 99% 6 of patients which

include stromal and neurotrophic keratitis,

anterior uveitis, scleritis and infectious retinitis and cranial nerve palsies.

Figure 1: Herpes Zoster vesicular dermatitis

involving first branch of Trigeminal nerve in a

HIV patient.

HZO can occur in both HIV-positive and

HIV-negative individuals. In HIV-infected

patients, HZO is extensive and relapsing and

occurs in relatively early stage of the disease, when CD4+ counts are above 200cells/µl.

7

Though HZO is not considered as an AIDS-

defining opportunistic infection, reports suggest that it affects 5-15% of HIV positive

patients and may be the initial manifestation

of HIV infection in young persons.5,7

In

Nigeria, herpetic eye disease constituted half of the ocular cases and studies have found

that over 60% patients with HZO are HIV-

positive in Nigeria.8,9

Generally, its occurrence in an apparently healthy middle-

HIV-related eye diseases


aged or younger person is an indication for

HIV testing. 10

Ocular complications result from

inflammation, nerve damage and tissue

scarring. The severity of the skin rash is an

important prognostic parameter of subsequent ocular involvement.

11 HIV infection also

appeared to correlate with more severe

corneal involvement and post-herpetic neuralgia.

6, 12

Patients with skin rashes near the eye may be

treated with oral acyclovir, bacitracin skin ointment for the skin lesions and acyclovir

eye ointment for conjunctival or corneal

involvement. In cases of acute retinal

necrosis (ARN) or cranial nerve involvement, intravenous acyclovir (10mg/kg body weight

three times a day for seven days) followed by

an oral maintenance regimen (800mg 3-5 times a day with slow taper over a month or

more) are indicated. Other options include

oral therapy with famciclovir or valaciclovir which are more expensive.

6,13

Kaposi Sarcoma

Kaposi sarcoma (KS), a vascular tumour

caused by human herpesvirus 8 (HHV-8), is

one of the earliest identified complications of AIDS and can be considered as an AIDS-

related illness.14

About 20% of HIV patients

have asymptomatic Kaposi sarcoma of the

eyelids, conjunctiva and rarely the orbit.15

Ocular adnexal KS typically presents as an

eyelid nodule or a red subconjunctival mass

that can be easily mistaken for hemorrhage (Figure 2).

Figure 2: Kaposi sarcoma appearing as a red subconjunctival mass in a HIV patient..

It does not invade the eye but may cause

discomfort through a mass effect or secondary corneal changes.

16,17 Large lesions

may be treated by surgical excision,

radiation, intralesional chemotherapy with

vinblastine or systemic chemotherapy in systemic involvement.

16,17 There are some

reports on HAART containing protease-

inhibitor such as saquinavir, indinavir, ritonavir and nelfinavir causing regression of

this tumor.18

Molluscum Contagiosum

Eyelid molluscum contagiosum (MC) is a

highly contagious skin lesion caused by the pox virus and is more prevalent in children in

underdeveloped areas. A cross-sectional

hospital based study in Uganda showed that over 10% of pediatric HIV patients had

MC.19

MC virus commonly infects the

eyelids and rarely the conjunctiva, cornea or limbus (Figure 3). Symptoms include chronic

follicular conjunctivitis, corneal micropannus

and epithelial keratitis.20,21

In HIV-infected

individuals, the classical papules with central umblication are larger than normal, more

disseminated and tend to recur within 6 to 8

weeks after removal. Since drug is not effective in treatment of MC, treatment

options include curettage, excision or

cryotherapy.21,22

However, the high

recurrence rate may make the original treatment a failure.

22

Figure 3: Molluscum contagiosum of the lower lid in a HIV patient


57

Ocular Surface Squamous Neoplasia

Squamous cell carcinoma is the third most

common AIDS-related neoplasm and the

most common sites involved in the eyes are

the conjunctiva and the eyelids. This is much more commonly seen in tropical, subtropical

and poor countries than in developed

countries.23

An increase in cases of conjunctival squamous neoplasia and HIV

infection has been shown in a study in

Uganda24

and they are believed to be related to exposure to ultraviolet light and human

papilloma virus infection. Diagnosis of this

neoplasia can be easily mistaken with

conjunctivitis and pterygium and the common mistake in treatment is simple

excision of the lesion which is usually

followed by a high recurrence after the surgery. Excision followed by cryotherapy,

radiation and chemotherapy and periodic

follow-up examination is needed to detect such recurrences.

25

Anterior segment manifestations

Infectious Keratitis

Varicella-zoster virus (VZV) and herpes simplex virus (HSV) most commonly cause

infectious keratitis in HIV-positive patients.

Keratitis due to VZV is usually associated

with HZO and complications include subepithelial infiltrates, stromal keratitis,

disciform keratitis, uveitis and secondary

glaucoma. Complications of HSV infection include dendritic and geographic epithelial

keratitis, stromal keratitis and and

iridocyclitis.2 In general, the course of both

these diseases is longer in AIDS patients.

Treatment for VZV keratitis is similar to that

of zoster ophthalmicus.13

Treatment of choice

for HSV keratitis consists of topical trifluorothymidine or trifluridine six to eight

times a day with debridement of the ulcer.

Oral acyclovir (400mg twice daily for 1 year) decreases the risk or recurrent keratitis by

50%. 26

Other causes of infectious keratitis are bacterial and fungal, most commonly

Candida species especially in intravenous

drug users.2 Spontaneous fungal keratitis

secondary to Candida parapsilosis and Candida albicans has been observed in

persons with advanced HIV disease.27

Uveitis/ Iridocyclitis Presence of uveitis in an HIV patient

warrants a thorough ocular examination to

rule out chronic infections that are common in these patients, such as tuberculosis,

syphilis, toxoplasmosis, histoplasmosis and

cryptococcosis. PCR sampling of the aqueous humor or vitreous may be helpful in

identification of those organisms.

Uveitis in association with reactive arthritis

may also occur as part of Reiter syndrome, consisting of asymmetric oligoarthropathy,

urethritis, and conjunctivitis or uveitis. This

syndrome appears to be more common in patients with HIV infection.

28

Some HAART medications such as rifabutin

and cidofovir, may also induce uveitis with cidofovir particularly causing an

endophthalmitis-like manifestation.29

Posterior segment manifestations

Retina

HIV Retinopathy

The most common ocular complication of

HIV infection is a retinal microvasculopathy called HIV retinopathy (Figure 4). It occurs

in 50-70% of patients with CD4+ cell counts

below 100 cells/ mm3.

3,30 It is a non-

infectious microvascular disorder

characterized by the presence of multiple

cotton-wool spots, intraretinal hemorrhages, retinal microaneurysms, telangiectatic

vascular changes and the presence of

capillary nonperfusion. 31

The cotton wool spots, which represent nerve fibre layer infarcts, are mainly located in the

posterior pole and usually do not affect visual

acuity. However, they can be confused with early cytomegalovirus (CMV) retinitis with

the differentiating factor being cotton wool

spots tend to be smaller, do not progress, superficially located and resolve over weeks

to months.



Figure 4: HIV microvasculopathy with typical cotton-wool spots.

Intraretinal haemorrhages and microaneurysms may be seen in AIDS

patients and are postulated to be due to

increased plasma viscosity and fibrinogen levels, circulating immune complexes and

infectious damage of the retinal

vasculature.31,32

Branch retinal artery and

retinal vein obstructions have also been seen in HIV infected patients.

33 It is advocated that

individuals with unexplained vascular

occlusions should be considered for HIV testing.

Microvascular changes are often

asymptomatic and no treatment is involved in

most cases.31,32

However, the severity of vascular damage correlates well with the

multiple opportunistic infections in AIDS

patients.30-32

Optic Disc

Noninfectious optic disc involvement in HIV

patients includes papilledema, anterior

ischemic optic neuropathy, and optic

atrophy.2 Papilledema usually occurs in

patients with advanced HIV disease with

increased intracranial pressure due to non-

Hodgkin‟s lymphoma, toxoplasma encephalitis and cryptococcal meningitis

2

(Figure 5).

Figure 5: Papilledema in a HIV patient with cryptocoocal meningitis.

Opportunistic Infections

Cytomegalovirus (CMV_) retinitis

CMV retinitis is the most common opportunistic ocular infection in patients with

AIDS. The incidence rate for CMV retinitis

was estimated to be 20% per year for those

with CD4+ counts ≤50 cells/µl and therefore, it‟s an indicator of advanced AIDS.

34,35 In

some patients, CMV retinitis may be the first

clinical manifestation of AIDS. Patients with CMV retinitis typically present

with floaters, blurred vision or visual field

loss, though some patients may be asymptomatic. Lesions usually appear in the

retinal periphery as white fluffy areas of

necrotizing retinitis associated with

hemorrhages and vascular sheathing. As areas of retinitis enlarge, they appear to

follow the vascular arcades resulting in an

arcuate or triangular zone of infection and if untreated, will eventually spread centrally

towards the macula and optic disc, and

haematogenously to the other eye36

(Figure 6).


59

Figure 6: Right eye inferotemporal confluent CMV retinitis involving the optic disc in a HIV patient.

Frosted branch angiitis may be seen in

conjunction with CMV retinitis (Figure 7). Blindness may result if the macula area is

affected or retinal detachment occurs due to

breaks in the necrotic retina (Figure 8).

A study by Doan et al.37

showed that HAART

medications reduced the incidence and prevalence of CMV retinitis (newly

diagnosed CMV retinitis was 6.1% before

HAART to 1.2% after HAART) and the

relapses of CMV retinitis were less frequent (36% before HAART vs. 17% after

HAART). HAART is also associated with

decreased progression of retinal necrosis and lower risk of retinal detachment, even though

it does not restore the vision where retinal

damage has already occurred.

Figure 7: CMV retinitis appearing as frosted branch angiitis.

Figure 8: Large retinal breaks noted at the necrotic area following a CMV retinitis infection in a HIV patient.

Anti-CMV therapy

The standard treatment for CMV retinitis is

induction therapy of intravenous Ganciclovir 5 mg/kg bd. for 2 to 3 weeks or until

stabilization of retinitis followed by

maintenance treatment. Alternatively, oral

valganciclovir, a ganciclovir pro-drug, at 900mg bd. may be used and it appears to be

as effective as intravenous ganciclovir for

induction treatment as well as effective for long term management of CMV retinitis as

shown by a controlled trial study by Martin et

al.38

Direct intraocular administration of ganciclovir has the benefit of achieving

therapeutic levels by bypassing the blood-

retinal barrier. Standard intravitreal doses

range from 2mg to 4 mg/ 0.1 ml administered twice a week, for up to 3 weeks, followed by

weekly maintenance injections. For patients

who do not respond to conventional treatment, concurrent intravitreal foscarnet at

2.4mg/0.1ml may be added to achieve

optimum control of disease.39

However, these

multiple intraocular injections carry a risk of retinal detachment and endophthalmitis and

may not be liked by patients. Alternatively,

ganciclovir intravitreal implant (a 6 mg pellet of ganciclovir is implanted into the vitreous

cavity via the pars plana incision and sutured

to the sclera to provide a sustained linear drug release for 3 to 6 months) is a local

treatment option that does not involve

multiple injections and avoids systemic side-

effects.40

On the downside, this implant does



not protect the fellow eye or protect against

systemic CMV infections. Other treatment options are intravenous

foscarnet that is associated with renal

insufficiency, and cidofovir therapy that has

ben associated with uveitis and hypotonia and has the potential for nephrotoxicity,

particularly in patients with kidney disease.29

Acute retinal necrosis (ARN) and Progressive

outer retinal necrosis (PORN)

Acute retinal necrosis (ARN) and progressive

retinal necrosis (PORN) are two distinct

forms of necrotizing herpetic retinopathy.

While ARN seems to occur at any level of CD4+ count, PORN typically occurs with a

CD4+ count less than 50cells/µl. 41

Presentation of ARN in HIV patients is similar to that in immunocompetent

individuals and is characterized by vitreous

inflammation, retinitis and vasculitis. PORN is characterized by fulminant, progressive

retinal necrosis with little vitreous

inflammation (Figure 9). PORN has a rapid

and progressive course leading to devastating vision loss and in most cases is difficult to

treat. 41 Intravitreal injections of ganciclovir

and foscarnet with combined intravenous antiviral drugs may be more effective in

treating this aggressive form of disease.

Figure 9: PORN in a multi-resistant HAART patient. Fundus photo is taken post retinal detachment surgery with silicone oil in the eye.

Ocular toxoplasmosis

Toxoplasmosis is the second most common

cause of ocular retinitis in patients with HIV,

affecting between 1% of AIDS patients in

USA 2 to 4.4% of similar patients in Brazil42

, depending on the seroprevalence of latent T.

gondii infection in the population.

Unlike immunocompetent patients who usually present with unilateral single

necrotizing lesions next to an old punched

out scar, patients with HIV may have diffuse or multifocal lesions, involvement of both

eyes, and relatively little vitreous

inflammation 43

(Figure 10). In contrast to

immunocompetent patients in whom ocular toxoplasmosis represents a recurrence of a

congenital infection, patients with HIV

usually have no evidence of a pre-existing retinochoroidal scar, suggesting recently

acquired infections.43

A high proportion of

these patients will also have concurrent cerebral toxoplasmosis, pneumonia or

disseminated infection.

Figure 10: Diffuse ocular toxoplasma retinochoroiditis in a HIV patient. PCR of vitreous sample was positive for Toxoplasmosis.

In HIV patients, ocular toxoplasmosis may be misdiagnosed as CMV retinitis. The

following are helpful differentiating signs: in

toxoplasmosis, the lesions appear as dense white-yellow exudates with fluffy borders,

there is absence of retinal hemorrhage unlike

CMV retinitis and the intraocular inflammation is more marked compared to

CMV retinitis. Patients with ocular


61

toxoplasmosis also frequently have a CD4+

count higher than those seen with CMV retinitis.

2,43 Serologic studies have been

relatively unreliable for the diagnosis of

toxoplasmosis in HIV positive patients since

the IgG anti-Toxoplasma antibody titers are sometimes low in these patients. However,

toxoplasmosis is unlikely in a patients with a

negative IgG anti-Toxoplasma antibody. The treatment consists of oral sulfadiazine,

combined with pyrimethamine or

clindamycin, or both. Trimethoprim-sulfamethoxazole is also effective. For

patients who are at increased risk of bone

marrow toxicity from sulphanamides,

atovaquone is an alternative. Maintenance therapy with pyrrimethamine-sulfadiazine or

pyrimethamine-clindamycin or trimethoprim-

sulfamethoxazole is recommended in recent studies to prevent relapses.

44

Ocular syphilis

Ocular syphilis occurs at any degree of

immunodeficiency and is often seen in HIV

patients with multiple sexual partners. Ocular syphilis manifests as anterior uveitis,

neuroretinitis, chorioretinitis, vitritis,

papillitis and retinal vasculitis.45

Up to 85% of patients with ocular involvement will have

evidence of central nervous system infection

and one third of them will manifest

symptomatic neurosyphilis.46

This high correlation between neurosyphilis and ocular

involvement supports the current

recommendation of lumbar puncture and cerebrospinal fluid (CSF) evaluation in HIV

patients with ocular syphilis.45,46

The

diagnosis of ocular syphilis can be confirmed by the serum fluorescent treponemal antibody

absorption test (FTA-ABS) and

microhemagglutination assay (MHA-TP).

CSF evaluations of protein, glucose and leucocyte and Venereal Disease Research

Laboratory (VDRL) have a high degree of

accuracy in the diagnosis of neurosyphilis. 46 Since HIV patients can have a more rapid and

aggressive syphilitic infection, a more

vigorous antibiotic treatment is recommended compared to immunocompetent patients.

Current treatment recommendation for all

HIV-positive patients with ocular syphilis is

similar to the regimen for neurosyphilis (12-24 million units of intravenous aqueous

penicillin G for a minimum of 10 days. Some

authors have also recommended maintenance

therapy since the ocular symptoms may recur. 47

Other infectious choroiditis

Tuberculosis

Tuberculosis is the single most important

HIV related opportunistic infection in

developing countries.48

In the developing world, 46% of HIV positive patients are co-

infected with tuberculosis and as many as

23% had disseminated ocular tuberculosis.49

Ocular tuberculosis can occur even with very

high CD4+ cell counts and common eye

findings that have been reported are choroidal tuberculomas, choroiditis and/or

phylectenules 48, 49

(Figure 11).

Figure 11: Disseminated choroiditis in a HIV patient with miliary TB.

Pneumocyctis carinii choroiditis

P. carinii choroiditis tends to occur in HIV patients with disseminated infection and has

an increased association with the use of

aerosolized pentamidine rather than systemic medication as prophylaxis for P. carinii

pneumonia.50

The disease is characterized by

round, yellow-white, subretinal lesions which

are scattered throughout the posterior pole, without associated intraocular inflammation.



Patients with P. carinii choroiditis are often

asymptomatic.50

Treatment is the same as that for pneumocystis pneumonia.

Cryptococcus chorioretinitis

Cryptococcosis is the most common fungal

infection occurring in 5-10% of all AIDS

patients. Central nervous system involvement with Cryptococcus neoforman in HIV

patients is relatively common and often

results in meningitis with secondary ocular findings.

2 A Sub-Sahara African study

showed that in Zimbabwe, 45% of meningitis

in adults is cryptococcal, and cryptococcal

meningitis is the third leading cause of death in HIV patients in rural Uganda. In Rwanda,

9% of patients with cryptococcal meningitis

developed visual loss and sixth nerve palsy.51

Cryptococcal infection may present as

papilledema due to increased intracranial

pressure from meningitis, optic atrophy with visual loss and multifocal choroiditis that

appears as multiple, discrete yellowish spots

with accompanying vitritis.52

Candida endophthalmitis

This infection is more likely in HIV patients with intravenous sources of infection

including indwelling catheters. Fungal

lesions appear as fluffy white infiltrates in the

choroid and may break through into the vitreous. It is usually accompanied by dense

vitritis and may form vitreous abscesses.

Treatment is with intravenous amphotericin.10

HAART and the eye

The use of highly active antiretroviral therapy

(HAART), which consists of a combination

of nucleoside reverse transcriptase inhibitors,

HIV protease inhibitors and non nucleoside reverse transcriptase inhibitors has decreased

plasma HIV viral load and increased CD4+ T

lymphocytes counts, improving the immune function of patients with HIV infection. 53,54

However, adverse side effects, drug

resistance and the emergence of immune reconstitution disease are the universal

problems associated with the usage of

HAART in HIV patients. Long-term use of

zidovudine may induce a mutation in the mitochondrial DNA that may account for the

late complication of Leber hereditary optic

neuropathy in patients with family history of

the disease.55

Zidovudine and protease inhibitors used alone can induce endothelial

cell proliferation and dysregulation of

angiogenesis which may make HIV patients more prone to hemangiomas such as KS.

56

Immune recovery uveitis is an inflammatory

condition in AIDS patients receiving HAART who had prior CMV retinitis.

57 It is

characterized by anterior uveitis, vitritis,

optic disc and macula edema. Complications

may include cataract, epiretinal membrane formation and cystoid macula edema. The

exact mechanism of this condition remains

unclear. It is generally believed to be caused by an increase in the immune response of the

host upon starting HAART treatment against

the persistence of CMV antigen in the host‟s eye. There are some reports showing that

protease inhibitors may be associated with

increased cytomegalovirus-specific

lymphocyte proliferation and production of inflammatory cytokines.

58 Another study

showed that the use of cidofovir as anti-CMV

therapy increased the risk of immune recovery uveitis.

59

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65

ORIGINAL ARTICLE

Sudan test (ST), a design of simple reading chart in

Arabic language with predicted magnification for low

vision

Atif B. Mohamed Ali1, Mohamed Elhassan A. Elawad

1, Elhadi A. Elsheikh

2

1Faculty of Optometry, Alneelain Univeristy, Khartoum, Sudan 2Ophthalmology department, Faculty of Medicine, University of Khartoum, Sudan

Correspondence to: Dr. Atif Babikir, Faculty of optometry; University of Alneelain, P.O 12702, Khartoum, Sudan. E-mail: atfbm@ yahoo.com. Tel: +249911371556.

Abstract AIMS: To assess near vision for subjects with low vision and to provide a quick method for

predicting magnification. MATERIAL AND METHODS: A reading test chart in Arabic language

using continuous meaningful text was designed for assessing low vision subjects. The Sudan test

(ST) uses fifteen paragraphs with 2 or 3 lines of related words in each paragraph. The font print size (horizontal case of word or font-thickness) decreases in a log MAR progression denominated

(ST.170 the largest size to ST.30 the smallest size) which equivalent to (15 M and 0.63 M) of meter

system. The reading ability at standard distances was taken to measure the resolution of acuity with ST and Bailey-Lovie near vision reading chart in 30 university subjects. RESULTS: There was

significant correlation in reading acuity between ST and Bailey-Lovie near vision reading chart in

each compared size. CONCLUSION: ST offers a reading acuity measurement for low vision Arabic

readers at 25 cm distance and quick calculated magnification for common reading.

Keywords: Arabic font, chart, low vision.

INTRODUCTION

There is a strong advocacy in favor of a geometrical progression of letter sizes used in

vision testing. Since Snellen′s original test,

which has been found to be close to a regular geometrical progression (a mathematical

series in which each number bears a constant

ratio to the previous one) this ratio is about 6√10 or a multiplier of 1.468. Bennett

1

pointed out, a constant ratio of 10√10 or

(1.2589 multiplier or 0.1 log unit) was

suggested as a geometrical progression of

letter size. This progression was chosen by

the Australian optometrists Bailey and Lovie2

to express visual acuity in terms of the

logarithm of the angular limb width (in min

of arc) of the smallest letters recognized at 6m (meter). This notation was termed log

MAR (minimum angle of resolution).

Relative magnification: Magnification is the ratio of the size of the image (formed by lens

system) to the size of the original object. This

ratio can be quantified by comparing the

transverse height of the image to that of the


original object. The type known as relative

magnification compares the size of the retinal image produced by the magnifier to the

retinal image size produced by the object,

when viewed at a standard distance without

the magnifier. Most of manufacturers assume a reference distance of 25cm (or 4D) for

calculation of the magnification value given

for their instruments; this value is equivalent to M=F/4 (M is the magnification and F is the

power of the lens). Specifically, relative

magnification can be used to predict the magnification required, and it is assumed to

be equal to the actual magnification only

when certain conditions are met; (a) the

patient is emmetropic or corrected for any ametropia, (b) the object is in the anterior

focal plane of the magnifier (image formed at

infinity), and (c) the reference object size (with which the magnified image is

compared) corresponds to a distance of

25cm.3

However, magnification required can be defined as the ratio of the present acuity

level over desired acuity level (enlargement

ratio) or letter size can read over letter size

wants to read. For this to be valid, both acuities must be referenced to the same

distance.4

MATERIAL AND METHODS

The chart described here is based on a

geometric progression of sizes and aimed to provide the clinicians with text for testing

near vision reading and the predicted

magnification for low vision persons. An example of this chart is shown in Figure 1. It

has the following design features.

Legibility: The text passages selected closely

resemble „normal every day reading‟ and

have simple linguistic content of continuous

paragraphs used from the common Arabic language.

Font-thickness: This term used to indicate the size (in mm) of the tool by which we can

write the Arabic words for example, tip of

pen (or the Nip size used in old writing of classical Arabic). For Latin alphabets the

height of a lower case letter such as “x” or

“o” should be used for measurement of visual

angle. For non-Latin alphabets the height of common, well known character should be

used. However, most of Arabic letters when

used for writing a word their shapes and

dimensions will change according to letter position in the word. Therefore in this design

the reference of calculation were based on the

measurement of font-thickness of words rather than height of letters. The

measurement reference was taken from any

part of the word that lies horizontally in the line. In other words, any part of the word

above or below the horizontal line excluded

from the measurement.

Font-thickness hypothesis: In design of this

test the font-thickness of the Arabic word

was assumed to be equal to one third (⅓) the height of the lower case of Latin alphabet in

each equivalent size.

Calculation of font-thickness: In the standard

Snellen chart letter height 8.73 mm seen at 6

m were defined 6/6 or equal to 0.0 log MAR,

and each gap of that letter subtend 1 min of arc 1. Consequently the height of a letter in a

standard distance 25 cm, which will be (0.25

X 8.73/6), equal to 0.36 mm. Therefore, from the font-thickness hypothesis the expected

font-thickness of word equivalent to (6/6) or

0.0 log MAR is equal to ⅓ X 0.36= 0.12 mm.

Font-thickness progression: The progression

of font-thickness used in this chart has a

constant ratio 10√10 and each step (paragraph) equal to exact multiplication

factor of 1.2589. Thus, the successive

increase of font size has a thickness 1.2589 times greater than that of the preceding size .

The first two decimal digits were written

without approximation (Table 1).

Printers′ type: The size of prints′ type was

selected carefully from the computer to be as

far as possible equal to the font-thickness calculated for each paragraph. A transparent

ruler and closed circuit television "CCTV"

were used to facilitate measure the font-thickness size.

Sudan Test (ST)

67

Acuity scaling: The chart contains fifteen

paragraphs. The font-thickness of each paragraph was calculated to be equivalent to

log MAR range from (1.7 to 0.3) at standard

reading distance 25cm.The term ST for

Sudan test and the number beside represents the acuity scaling. For example, ST.30 means

equivalent font-thickness to log MAR 0.3

multiplied by 100 (Table 1). Magnification: The relative size (enlargement

ratio) was used for predicting the required

magnification, the ratio calculated according

to the critical print size the subject can read

to the target size which in this test is ST.40

(font-thickness 0.27mm) ,thus each font thickness was divided over 0.27mm. An

approximation of calculations up to ± 0.25

was used (Table 1).

Number of words: Different meaningful

words selected according to length of word

and font size were arranged as followings; ST.(170 to 140) have an average of 6 words

in each paragraph, ST.(130 to 100) have an

average of 10 words in each paragraph, and ST.(90 to 30) have an average of 22 words in

each paragraph.

Table (1): Shows the calculations of ST font size and magnifications

M.System

Mag (X)

Font (mm)

ST.No

LogMAR

0.32

-

0.12

-

0.0

0.4 - 0.15 - 0.1

0.5 - 0.18 - 0.2

0.63 - 0.22 30 0.3

0.8 - 0.27 40 0.4

1.0 1.2 0.33 50 0.5

1.25 1.5 0.41 60 0.6

1.6 1.9 0.51 70 0.7

2.0 2.4 0.64 80 0.8

2.5 3.0 0.80 90 0.9

3.2 3.7 1.00 100 1.0

4.0 4.5 1.25 110 1.1

5.0 5.8 1.57 120 1.2

6.3 7.3 1.97 130 1.3

8.0 9.0 2.48 140 1.4

10 11.6 3.12 150 1.5

12.5 14.5 3.92 160 1.6

15 18.0 4.93 170 1.7

CHART EXPERIMENT

The aim of the experiment was to compare the reading acuity of this test with a more

established test in English language. The

design of Bailey-Lovie Reading chart version W10 was used which has fourteen reading

steps scaled from 5.0M to 0.25M.

Criteria of experiment

Thirty (30) university students aged 18 to 24 were recruited from the Faculty of Optometry

at Alneelain university to perform the

experiment. The inclusion criteria for the invited students were visual acuity not less

than 0.0 log MAR at distances 4 meter for

distance with "E" chart, and 40cm with Bailey-Lovie for near. Refraction should be

normal and the better eye among the two eyes

was used for testing. The selected group

should be fluent Arabic readers and their English reading ability was checked before

experiment. All tests in this experiment were

conducted by the same examiner. Examination with ST chart and Bailey-Lovie

chart were conducted in the same visit at two

testing session (2hours a part) for each

student separately.

METHOD OF EXPERIMENT

The examiner hold The ST chart in front of the student at the following distances (steps)

consecutively; 6.3M, 5M, 4M, 3.2M, 2.5M,

2M, 1.6M, 1.25M,1.0M,0.8M, 0.63M, 0.5M. A tape measure was used to measure the

distance from the eye to the chart. In each

distance (step) the student was encouraged to

read a loud from the larger visible words till the text were either missed or misread. The

objective scoring system based on the critical

print size (CPS) at which the student can read perfectly (no error). This CPS was written

corresponding to the distance step and at the

same time the CPS provides the reading acuity (RA) limit of the student. The same

procedure was followed for the Bailey-Lovie

Sudan Test (ST)


chart after rest of two hours. The Pearson‟s

correlation was calculated using SPSS

(version, 10) between the two charts scoring

and the results shown in Table 2.

Table (2): Shows correlations between ST and Bailey-Lovie

Significant level Correlations Bailey-Lovie and %

scored

ST and %

scored

Test distances in

meters

0.01 0.590 M5 (76.7%) 120 (76.7%) 5

0.01 0.756 M4 (70%) 110 (80%) 4

0.01 0.631 M3.2 (73.3%) 100 (76.7%) 3.2

0.01 0.518 M2.5 (73.3%) 90 (63.3%) 2.5

0.01 0.518 M2.0 (76.7%) 80 (60%) 2.0

0.05 0.437 M1.6 (76.7%) 70 (56.7%) 1.6

0.05 0.438 M1.25 (76.7%) 60 (56.7%) 1.25

0.01 0.467 M1.0 (73.3%) 50 (60%) 1.0

0.01 0.502 M0.8 (70%) 40 (46.7%) 0.8

0.01 0.545 M0.63 (73.3) 30 (53.3%) 0.63

DISCUSSION

The method of measuring the visual acuity

(VA) with single letter or symbols is familiar; the basic principle of measuring VA with

these charts is that the smallest character that

can just be recognized satisfactorily provides the index of VA. But, difficulties rise when a

patient achieves a high score on such acuity

test and yet perform poorly on a practical task like reading. This means that these particular

tests of visual performance are not optimal in

describing the patient ability to perform (real)

visual task. However, reading with low vision is difficult even under the best circumstances.

To obtain an estimate of reading ability a

continuous text is probably better than isolated letters. On the other side, the

selection of a trial visual aid is generally

based on acuity. Thus, it is not recommended

that distance VA should be used to predict near magnification.

A multitude of different reading charts have

been suggested, most of them were written in English or other languages that are not

suitable for most of the people in our country.

Therefore, in this test we used the Arabic language which is the spoken and written

language in Sudan. The computers auto-

control has been used for words and row

spacing. This control provides the minimum gap, which prevents overlap between words

and rows, such situation is usually found in

written Arabic.

When the ST chart was compared with

Bailey-Lovie chart, significant correlation in the experiment was achieved. This clearly

shows that the ST test chart is useful and

valid chart for testing near vision. Although

Bailey-Lovie chart has no size bigger than M5 which was successfully compared to

ST.120. But it is expected for the other larger

sizes of ST (130, 140, 150, 160, and 170) to be comparable with Bailey-Lovie system

because it follows the same progression.

However, the biggest paragraphs were only

needed for those with profound low vision. The reference „target‟ size used for

calculations of magnification was ST.40,

which is smaller than the commonly reading prints found in the ordinary books or

newspapers. A smaller paragraph ST.30 was

used for assessment in case a patient needs to use more small print size.

Sudan Test (ST)

69

Figure 1: Shows ST design (diminished to approx. 25% of actual size)

Figure 2: Shows the Bailey-Lovie reading chart (diminished to approx. 25% of actual size)

Sudan Test (ST)


Acknowledgements

The authors would like to acknowledge Professor Ian Bailey the inventor of Bailey-

Lovie chart for his knowledgeable guidance

to perform the experiment. Also we

acknowledge Dr. Christine Dickinson the editor of Ophthalmic and Physiological

Optics for her great advices. Also we

appreciate the encouragement given by Mr. Hassan Minto of Sight Savers international,

and Dr. Kamal Hashim the coordinator of the

National Programme for Prevention of Blindness in Sudan.

References 1. Rabbetts R B. Visual acuity and contrast sensitivity.

In: Bennett and Rabbetts′ Clinical visual optics, 3rd

edn, Butterworth- Heinemann, 2000; pp.20 – 29. 2. Bailey I L, Lovie J E. New design principles for

visual acuity letter charts. Am J Optom 1976; 53: 740 – 45.

3. Woo G C, Mah-Leung A. The term magnification. Clin.Exp.Optom 200); 84: 3: 113 – 19.

4. Rosenthal B P, Cole R G. Visual acuity and the predicted reading add. In: Functional assessment of

low vision, Mosby, London, 1996; pp.28.

Sudan Test (ST)

71

ORIGINAL ARTICLE

Toxic effects of antiglaucoma topical medications on

the conjunctiva – a histological study Mehida Hayet, Moulessehoul Soraya, Tou abdenacer, Ouadah Myriam 1 Biotoxicology laboratory, djillali liabes university, Algeria 2 Anatomo-pathology department, djillali liabes university, Algeria 3 Ophthalmology department, CHU Tlemcen, Algeria

Correspondence to: Mehida Hayet, Biotoxicology laboratory, djillali liabes university, Algeria. Tel:

+213775868249, email: [email protected]

Abstract

AIMS: To evaluate the extent of epithelial conjunctival changes associated with prolonged use of topical

glaucoma medications. MATERIAL AND METHODS: forty eye of glaucomatous patients treated with various

eye drops (Timolol, Trusopt, Pilocarpine and Xalatan) and for different lengths of time were selected and

classified in five groups: the first group received Timolol, second was treated with Timolol and Pilocarpine,

the third one with Timolol and Trusopt, the fourth with Timolol, Trusopt and Pilocarpine, finally the last

group with Xalatan. The Conjunctival inflammation was evaluated with light microscopy.

RESULTS: Examination of the conjunctival biopsies revealed profound changes on the histological

parameters, an inflammatory reaction on the connective fabric with a vascular congestion, oedema and a

leucocytic inflammatory infiltrate, a disappearance of caliciform cells, exulceration of the mucous membrane, abrasion and malpighien metaplasia on the epithelium. The frequency of appearance of these deteriorations

is according to the treatment and to its duration. CONCLUSION: Although the adverse effects of glaucoma

medications on the ocular surface are likely multifactorial. We noted that the use of only one drug, applied

for more than 10 months causes significant modifications concerning the histology of the connective tissue. In

addition, the application of a combined therapy revealed more conjunctival lesions than the mono therapy.

Keywords: Glaucoma; Eye drops; Conjunctiva; Toxic effect; Histology.

INTRODUCTION The chronic glaucoma with open angle poses

a major problem of public health; it is the

second leading cause of blindness in the world.

1 It is defined by the presence of

elevated Intraocular pressure.2 It touches

approximately 1 to 2% of the population

more than 40 years, its incidence increases with the age.

3 Its treatment requires a long

and prolonged therapy by eye medication.4

However the prolonged use of these eye drops can induce histological changes on the

ocular surface.

The local application of the antiglaucoma eye

medications is generally well accepted however various types of conjunctival

reactions can occur.5,6,7

The epithelial barriers

conjunctival and corneal are the principal

ways of entry of these eye medications in the ocular tissues,

8 but the majority of the actives

molecules pass with difficulty through these

barriers because of their hydro solubility. Therefore, wetting agents equipped with

detergent properties are needed to increase

their effectiveness, which also allow the

preservation and the sterility of the eye medications long duration. Prolonged use of

eye medications with preservatives presented

a certain risk to ocular surface,9, 10, 11

such as thickness of sub epithelial collagen of

conjunctiva,12

a chronic subclinical

inflammation as shown by the presence of

immunologic changes and inflammatory infiltrates.

13

In Algeria this is the first study realized in

this field it was undertaken to determine the


histolocical changes in the conjunctiva in

patients who were treated with different types of antiglaucoma topical medications for

variable period of time.

MATERIAL AND METHODS This study was done in the ophthalmology

department of the CHU Tlemcen and the

CHU of Sidi Bel Abbes (west Algeria) over a period of 36 months.

Conjunctival biopsies were taken from 40

eyes of open angle glaucoma, aged 40 years and above, they were treated with different

types of eye medications for varying period

of time.

All patients who were presented to these departments during the period of study, and

planned for the cataract surgery or glaucoma

surgery was included; Biopsies were taken from the infero-temporal bulbar quadrant

with a biopsy forceps. The biopsies were

divides into 5 groupes according to the type of eye medication used, the first group (13

samples) from the patients treated with

Timolol alone, ( betabloquant); the second

group (7 samples) from patients treated with Timolol –trusopt (betblaoqant and inhibitor

of the carbonic anhydrase) combination, the

third group (05 samples) from patients treated with Timolol - pilocarpine

(betabloquant and myotic) combination the

fourth group (03 samples) from patients

treated with Timolol, Trusopt and Pilocarpine (betabloquant, inhibitor of the carbonic

anhydrase and myotic) combination, and the

fifth (12 samples) from patients treated with Xalatan (prostaglandin) alone. The durations

of treatment varied from 06 months to 18

years. Only two biopsies were taken from healthy

conjunctiva as controls, The specimens were

fixed and carried out according to usual

techniques' of light microscopy14

Hemalun – éosine stain was used in this study.

RESULTS: The histological features of healthy

conjunctiva showed a laminated prismatic

epithelium comprising caliciform mucous cells resting on its basal membrane of a

chorion of connective tissue (figure 1).

Figure 1: Histological cut of healthy conjunctiva Bar = 1.5cm = 100μ

The histological analysis of 40 biopsies showed several changes in the epithelium and

connective fabric. We noted a squamous

metaplasia (figure 2) in 34 patients on the whole.

Figure 2: Malpighien métaplasia, leucocytic infiltrate and oedema bar = 1.5cm = 100μ

However, this was not seen in the conjunctiva of patients treated with Xalatan alone (3

samples) and Timolol alone (03 samples) for

less than 10 months period.

Also we noted a vascular congestion (figure 3) in all the analyzed biopsies. A

disappearance of the caliciform cells (figure

4) in all the biopsies except in 3 patients treated with Timolol alone for 11, 15 and 18

years and in 2 patients treated with Xalatan

alone for 7 and 12 years.

Toxic effect of antiglaucoma eye drops

73

Figure 3: General aspect of the inflammatory process Bar = 1.5cm = 100μ

Figure 4: Malpighien metaplasiea with disappearance of the Caliciform cells (Bar = 1.5cm = 100μ)

Antiglaucoma treatment containing two eye medications Timolol - Trusopt combination

and Timolol-Pilocarpine combination caused

an oedema accompanied by leucocytic

inflammatory infiltrate on the chorion (figure 2), and epithelial abrasion in patients treated

for more than 24 months. In addition to these

lesions we noted an exulceration of the epithelial mucous membrane among htree

patients treated by the three-drug therapy,

one case of Dissolution of the chorion was noted in a patient treated with three drugs for

more than 3 years (figure 5).

Figure 5: Inflammatory elements (presence of polynuclear) With dissolution of the chorion. Bar = 1.5cm = 100μ

DISCUSSION

All these lesions constitute the inflammatory process which results in the reactional

phenomenon initiated by the aggression of a

pathogenic agent which ends with the

cicatrization.15

In all the subjects practically we observed the presence of congestive

vessels which are variable according to the

duration and type of treatment, more the treatment is complicated and long, more the

vascular congestion is significant. It is due to

a vasodilatation occurring after a short phase of vasoconstriction.

16

An absence of the caliciform cells was in

particular noticed in the patients treated with

the monotherapy only for a very long duration (exceeding 07 years of treatment), it

is possible that it has a reappearance of these

cells after adaptation of these subjects to their treatment.

Also a significant thickening of the

epithelium (malpighien metaplasia) was observed among 34 patients (85%) of the

biopsies this could be a means of defense

against the external aggressions, the

epithelium becomes increasingly thick, by transforming into more stratified wich should

not be seen in the conjunctiva of the eye 16.

These results are in agreement with works of Brandt,

17 and Broadway,

18 who reported

squamous metaplasia associated the use of a

great number of anti glaucoma eye

medications. Several investigators19, 20, 21

had noticed morphological variations of

conjunctiva, (an increase thickness of

epithelial fabric), in patients treated with the Timolol and Pilocarpine for various lengths

of time. Metaplasia of conjunctiva was noted

in 26.6% of patients treated with beta-blockers for 12-24 months, which increased

to 42.8% when the duration of treatment was

longer.22

It was also seen in patients treated

with beta-blocker and myotic combination for 12-24 months (60%) which increased to

70% in cases treated for several years.

More therapy is combined more it has pathological lesions. A presence of a

leucocytic inflammatory infiltrate and an

oedema were noted among patients treated with the combination of two eye medication

(group 2 and 3), also we could note that the



more therapy is prolonged the more other

histo-pathological changes appear such as the abrasion of the epithelium which was noticed

in the patients subjected to more than 24

months to this same treatment. The studies

carried out in this field did not describe this phenomenon. The combination therapy with

the three drugs caused an exulceration of the

epithelial mucous membrane, which was found among all patients belonging to the 4

th

group. In contrary, dissolution was noted in a

patient having received this same medication but for a period exceeding three years of

treatment.

Histo-pathological studies reported by

Baudouin et al23

, and De Saint Jean et al.24

confirmed that antiglaucoma eye medications

can exert toxic effects on the conjunctiva and

the cornea surface, they induce chronic inflammation, the origin of this inflammation

is not yet well determined but the chloride of

Benzalkonium, which is used as preserving agent in a majority of eye drops seems to

have an obvious toxicity on the ocular

surface.

Noecker et al25

reported that corneal and conjunctival epithelium faded with

inflammation in 16 rabbits who received

different anti-glaucoma eye drops, our observation of this finding is similar to the

studies of Mietz et al 26

and Langer et al. 27

The histopathological examination of the

conjunctival biopsies taken from 40 glaucomatous patients treated for various

lengths of time (6 months to 18 years), in

mono therapy and in combination therapy revealed several pathological changes

concerning the aspect of epithelial fabric and

that of connective tissue. Indeed we observed a vascular congestion, an oedema

and an inflammatory infiltrate on the chorion,

as well as an absence of the caliciform cells,

an exulceration of the mucous membrane, an abrasion and finally a metaplasia at the

epithelial level.

The whole of these changes initiate the inflammatory process started by the

aggression of an external agent (eye

medications). Our study showed that the use of only one eye medication for more than 12

months causes the appearance of significant

histological changes of the conjunctiva; on

the other hand the use of a combination therapy of two and three eye drops revealed

more pathological changes than the mono

therapy. The frequency of appearance of

tissue deteriorations is according to the number of drugs used and the duration of

treatment.

References: 1. Adrian SB, Justin OF, Daniel M and Peter GS,

Posterior Eye Disease and Glaucoma A-Z edition Elsevier 2008; 125-132.

2. Maugery J, Rougier J. Ophtalmologie pratique edition simep. 1979; 132-150.

3. Alicja RR , Cristopher GO. Identification & Co-management, Edited by David F E R, and Alicja R R, Elsevier 2007; 1-16

4. Thylefors B, Resnikoff S. Conférence technique de

l‟OCCGE, progrès réalisés dans la lutte contre la cécité dans le monde et perspectives d‟avenir. Cahier santé. 1998; 8 : 140-143.

5. Turaçli E, Budak K, Kaur A, Mizrak B, Ekinci C. The effects of long term topical mediaction on conjunctival impression cytology. International ophthalmology. 1997; 21: 27-33.

6. Nuzzi R, Finazzo C, Cerruti A. Adverse effects of

topical antiglaucoma medications on the conjunctiva and the lacrymal response.Int. ophthalmol. 1998; 22: 31-35.

7. Cvenkel B, Alojz I. Ocular surface changes induced by topical glaucoma monotherapy. Ophthalmologica; 2002; 216: 175-179.

8. Ravet O. Les effets délétères de certains collyres sur la surface oculaire. Bull. soc. Belg ophtalmol. 2007; 304: 145-149.

9. Pisella P, Lala E, Parier V, Brignole F, Baudouin C. Retentissement conjonctival des conservateurs : étude comparative de collyres bétabloquants conservés et non conservés chez des patients glaucomateux. Journal français d‟ophtalmologie. 2003 ; 26 : 675-679.

10. Baudouin C. Detrimental effect of preservatives in eyedrops implications for the treatment of

glaucoma. Acta ophthalmologica. 2008; 86: 716-26.

11. Tadashi I, Hiroshi O, Kazuhisa M, Ikuyo O, and Mitsuru N. Effects of Antiglaucoma Drops on MMP and TIMP Balance in Conjunctival and Sub conjunctival Tissue. Investigative Ophthalmology and Visual Science. 2006; 47: 823-830.

12. Mietzh, NU, Krieglstein GK. The effect of

preservatives and antiglaucomatous medication on the histopathology of the conjunctiva, graefes arch clin exp ophthalmol 1994; 232: 561-565.

13. Baudouin C 1996, side effects of antiglaucomatous drugs on the ocular surface Curr ophthalmol 1996; 7: 80-6


75

14. Beverlander G. Eléments d‟histologie. the C.V mostby company – St Louis, Sixième édition. Maloine S.A éditeur Paris 1973; 305-320.

15. Leeson T.S., Leeson R. C. (1980). Histologie. Deuxième édition Masson 1980; 258-269.

16. Hould R. Histologie descriptive. Decarie, éditeur Montréal; Maloine, éditeur Paris 1983 ; 563-588.

17. Brandt JD, Wittpen JR, Katz LJ, Steinmann WN, Spaeth GL. Conjunctival impression cytology in patients with glaucoma long-term topical medication. American Journal of Ophthalmology. 1991; 112: 297-301.

18. Broadway DC, Grierson I, Stürmer J, Hitchings RA.

Reversal of topical antiglaucoma medication effects on the conjunctiva. Archives ophthalmology. 1996; 114: 262-267.

19. Broadway DC, Grierson I, O‟brien C, Hitchings RA. Adverse effects of topical antiglaucoma medication. The conjonctival cell profile. Arch ophthalmol. 1994; 12: 1437-1445.

20. Baun O, Heegaard S, Keesing SV, Prause JU. The

morphology of conjunctiva after long-term topical antiglaucoma treatment. A quantitative analysis. Acta ophthalmologica scandinavica. 1995 ; 73: 242-245.

21. Mietz H, Schlötzer SU, Strassfeld C, Krieglstein GK. Effect of Latanoprost on the histopathology of

conjunctiva. Invest ophthalmol vis sci. 2001; 42: 679-687.

22. Wroblewska E. Squamous métaplasia of bulbar conjunctiva in the course of term topical antiglaucoma thérapy. Klin Oczna 1999; 101: 41-

43. 23. Baudouin C, Ettaiche M, Gastaud P. Experimental

study on corneo conjunctivalside effect of preservative solutions. Ophtalmologie. 1996;10: 376-379.

24. De Saint Jean M, Debbasch C, Brignol F, Rat P, Warnet JM, Baudouin C. Toxicity of preserved and unpreserved antiglaucoma topical drugs in an

invitro model of conjunctival cells. Current eye research. 2000; 20: 85-94.

25. Noeker R, Herrygers L, Anwaruddin R.. Corneal and Conjunctival Changes Caused by Commonly Used Glaucoma Medications. Cornea. 2004; 23: 490-496

26. Mietz H, Niesen U, Krieglstein GK. The effect of preservatives and antiglaucomatous medication

histopathology of the conjunctiva. Graefes Arch Clin Exp Ophthalmol. 1994; 232 :561-565.

27. Langer K, Mutschler E, Lambrecht G, Mayer D, Troschau G, Stieneker F, Evaluation as drug delivery system for ophthalmic applications. International journal of pharmaceutics. 1997; 158: 219-231.



ORIGINAL ARTICLE

Laser-assisted in situ keratomileusis (LASIK) surgery in

the management of anisometropic amblyopia in

Sudanese Children

Kamal H Binnawi 1

, Nadir A M Ali2

1Cornea department, Sudan Eye Center, Khartoum, Sudan 2Research department, Sudan eye Center, Khartoum, Sudan

Correspondence to: Dr. Kamal Hashim Binnawi, Cornea department, Sudan Eye Center, Khartoum, Sudan. E-mail: [email protected]. Tel: +249912309628

Abstract

AIM: To evaluate the use of LASIK followed by occlusion therapy for the management of

anisometropic amblyopia in children. MATERIAL AND METHODS: Twenty six children aged between 5 and 15 years with anisometropic ambyopia who failed conventional treatment with

optical correction and occlusion were included in the study. LASIK was done for the selected

patients, and they were followed up for one year after surgery. All patients continued postoperative

amblyopia therapy that included patching of the good eye according to the individual needs and wearing spectacles with the full cycloplegic refractive correction in both eyes. Pearson’s bivariate

correlational analysis was done to study possible associations between the different variables. A p-

value of 0.05 or less was considered statistically significant. RESULTS: Twenty six children were included in this study (16 females and 10 males). The mean age was 9.5 ± 3.5 years. All LASIK

procedures were uneventful under general anesthesia. All children had improved in terms of

UCVA, BCVA and refraction at one-year follow-up examination, and none of these children has

shown myopic regression after 12 months. There was no significant correlation between age/gender and postoperative UCVA, BCVA and Refraction. CONCLUSION: LASIK is a safe and effective

procedure for the treatment of myopic anisometric amblyopia.

Keywords: LASIK; anisometropic amblyopia; high myopia; Sudanese; Children.

INTRODUCTION

Amblyopia is the commonest cause of visual

impairment in children. The prevalence in

childhood is estimated worldwide to be around 1% to 4%. Laser-assisted in situ

keratomileusis (LASIK) is a well established

procedure used for the treatment of myopia, hypermetropia, and astigmatism in adults.

1

Photorefractive keratectomy (PRK) and

LASIK are reported to be beneficial in children with myopic anisometropia

associated with amblyopia.2,3

It has been

reported that visual acuity and binocular

vision outcomes were significantly better in

children who received permanent surgical

correction of anisometropia than in those who

were conventionally treated using contact

lenses.4,5

Davidorf et al6 and Medcedeva et

al7 have also suggested that refractive surgery

is indicated in the treatment of high

hyperopic anisometropic amblyopia in children. The visual outcomes of LASIK in

adolescents with anisometropic amblyopia

were previously studied among Sudanese population.

8 This study illustrates the effect

of LASIK procedure in lowering myopic

anisometropia in children, with one year of

follow-up, to assess its effect in the treatment

77

of high anisometropic amblyopia in 26

Sudanese children.


Twenty six children aged between 5 and 15

years with anisometropic ambyopia due to myopia underwent LASIK in the amlyopic

eye. The target was decreasing the difference

in refraction (to eliminate anisometropia) or emmetropia of the operated eye and

refractive status of the other eye. Selection of

patients was on the basis of failed conventional amblyopia treatment with

optical correction and occlusion, or

intolerance to contact lenses and spectacles.

Informed consent for the procedure was obtained from the parents.

The patients received a full eye examination

preoperatively, including visual acuity, dilated funduscopy, refraction, corneal

topography and pachymetry. Visual acuity

was measured with Kays pictures or Snellen chart, according to age. Pilocarpine 1% was

instilled preoperatively to prevent distracting

hippos. All children underwent the surgery

under general anaesthetia. The eye was cleaned with 5% povidone iodine solution.

The surgical site was draped.

A flap measuring between 8.5 mm and 9.5 mm was created and hinged superiorly, using

Moria M2 microkeratome. Allegretto

excimer laser (Wavelight) was used. The eye

tracker was engaged during the surgery. The optic zone measured from 5.5–6.0 mm.

Postoperatively, a clear plastic shield was

applied. Postoperative topical medication included Maxitrol eye drops four times daily

for 5 days and Voltaren eye drops four times

daily for one week with Tears Naturale eye drops four times daily and Hypotears gel at

night time for one month. The shield was

advised to be used during sleep for 2 weeks.

All patients continued postoperative amblyopia therapy that included patching of

the good eye according to the individual

needs and wearing spectacles with the full cycloplegic refractive correction in both eyes.

A p-value of 0.05 or less was considered

statistically significant. Pearson‟s bivariate correlational analysis was done to study

possible associations between the different

variables.

RESULTS

Twenty six children were included in this

study. Sixteen were females and 10 were males. The mean age was 9.5 ± 3.5 years. All

children had improved in terms of UCVA,

BCVA and refraction (SE) at one-year follow-up examination (Figure 1, 2 and 3),

and none of these children has shown myopic

regression after 12 months. There was no significant correlation between

age and postoperative UCVA, BCVA and

Refraction (p=0.45, p=0.14, p=0.79

respectively). Similarly, no significant correlation was found between gender and

the above mentioned variables (p=0.48,

p=0.63, p=0.21 respectively). Those who had better BCVA preoperatively had better both

UCVA and BCVA postoperatively (p=0.03,

p<0.001 respectively). Similarly, higher preoperative value of spherical equivalent of

refraction was associated with higher

postoperative value (p<0.001).

None of the patients included in the study had any postoperative complications.

DISCUSSION Amblyopia is a major health problem among

children in Sudan. In a previous study done

among internally displaced people in

Khartoum state, the prevalence of amblyopia was found to be 32.5%, and it was the second

leading cause of blindness.9

The use of refractive surgery in the treatment of refractory cases of anisometropic

amblyopia is not new. Many studies proved

that excimer laser can safely and effectively correct anisometropia and improve

amblyopia in children.2-7 Payssee et al10

in

their case series of 11 children aged 2 to 11

years with refractory anisometropic amblyopia concluded that pediatric PRK can

be safely performed for anisometropia with

similar response of refractive error compared to adults; visual acuity and stereopsis

improved, so PRK may play a role in the

management of anisometropia in selected pediatric patients. On the other hand, Astle et

al11

assessed the refractive, visual acuity and

LASIK in management of anisometropic amblyopia


binocularity outcomes in 53 children (aged

10 months to 16 years) with various levels of anisometropic amblyopia that were treated by

laser assisted subepithelial keratectomy

(LASEK). Postoperatively, 63.6% of children

had an improvement in BCVA and the remainder had no noted change. In our study,

all patient included in the study did have

improvement in postoperative BCVA one year after performing LASIK.

The use of LASIK in the management of

uniocular high myopia was previously studied by Agrawal et al

2 in 16 eyes of

children with anisometropic myopia. They

found that LASIK for uniocular high myopia

in pediatric eyes provided encouraging results in the management of selected cases

of anisometropic amblyopia when other

measures failed. Our study supports this

assumption, as all children included (who failed conventional treatment) had improved

postoperatively.

There is still ongoing controversy over the

safety of LASIK in pediatric patients. The main problem is that children are vulnerable

to some complications, such as refractive

regression, glare due to the smaller optical zone, and decreased contrast sensitivity.

12 In

our study, none of the patients had any

intraoperative and/or postoperative complications.

In conclusion, LASIK is a safe and effective

procedure for the treatment of myopic

anisometric amblyopia.

Figure 1: Line chart showing the relationship between preoperative and postoperative UCVA among the 26 patients.


79

Figure 2: Line chart showing the relationship between preoperative and postoperative BCVA among the 26 patients.

Figure 3: Line chart showing the relationship between preoperative and postoperative Refraction among the 26 patients.



References

1. Carones F, Vigo L, Scandola E. Laser in situ keratomileusis for hyperopia and hyperopic and mixed astigmatism With LADAR Vision Using 7-

to 10-mm ablation diameters. J Refract Surg 2003; 19: 548-554.

2. Agarwal A, Agarwal A, Agarwal T et al. Results of pediatric laser in situ keratomileusis. J Cataract Refract Surg 2000; 26: 684–689

3. Wang H, Yin ZQ, Chen L et al. LASIK for high myopia and high myopic astigmatism in children. Chinese J Strabismus Pediatr Ophthalmol 2003; 11:

229–233. 4. Autrata R, Rehurek J. Laser-assisted subepithelial

keratectomy and photorefractive keratectomy versus conventional treatment of myopic anisometropic amblyopia in children. J Cataract Refract Surg 2004; 30: 74–84.

5. Paysse EA, Coats DK, Hussein MAW, et al. Long-term outcomes of photorefractive keratectomy for

anisometropic amblyopia in children. Ophthalmology 2006; 113: 169–176

6. Davidorf JM. Pediatric refractive surgery. J Cataract Refract Surg 2000; 26: 1567–1568

7. N. I. Medcedeva and V. M. Sheludchenko. Choice of surgical correction method in hypermetropic anisometropia in children. Vestn-Oftalmol 2003; 119: 14-18

8. Binnawi KH, Mursi S, Ali NA. The use of laser in

situ keratomeleuisis in the management of refractory anisometropic amblyopia in Sudanese adolescents. Int J Ophthalmol 2009;1: 21-24

9. Zeidan Z, Hashim K, Muhit MA et al. Prevalence and causes of childhood blindness in camps for displaced persons in Khartoum: results of a household survey. East Mediterr Health J 2007;13:580-585

10. Paysse EA, Hamill MB, Hussein MA et al. Photorefractive keratectomy for pediatric anisometropia: safety and impact on refractive error, visual acuity, and stereopsis. Am J Ophthalmol 2004; 138:70-78.

11. Astle WF, Rahmat J, Ingram AD et al. Laser-assisted subepithelial keratectomy for anisometropic amblyopia in children: outcomes at 1

year. J Cataract Refract Surg 2007; 33:2028-2034. 12. Lin X, Yan X, Wang Z, et al. Long-term efficacy of

excimer laser in situ keratomileusis in the management of children with high anisometropic amblyopia. Chinese Med J 2009;122:813-817.


81

ORIGINAL ARTICLE

Visual Outcome of Phacoemulsification in Al Walidain

Charity Eye Hospital – the first 120 cases. Mustafa Abdu Ali

1, Kamal Hashim Binnawi

2, Nadir Ali Mohamed Ali

3

1Faculty of Optometry and Vision Sciences, University of Alneelain, Khartoum, Sudan 2Al Walidain Charity Eye Hospital, Omdurman, Sudan 3National Programme for Prevention of Blindness, Khartoum, Sudan

Correspondence to: Mustafa Abdu Ali, Faculty of Optometry and Vision Sciences, University of Alneelain, Khartoum, Sudan. Tel: +249122630711, Email: [email protected]

Abstract AIM: To study the visual outcome of phacoemulsification in Walidain Charity Eye hospital, Sudan

MATERIAL AND METHODS: The first 120 consecutive patients who underwent

phacoemulsification in Walidain Charity Eye hospital, Omdurman, Sudan were retrospectively

studied. Demographic data, best-corrected visual acuity (BCVA) preoperatively, keratometry readings, axial length, BCVA postoperatively and postoperative refraction after 6 months were the

main variables studied. Data analysis was done using SPSS version 13.0. Descriptive and bivariate

correlational analyses were the main statistical tests used. The p value < 0.05 was considered as significant. RESULTS: The mean age was 61.1 ± 10.58 years. Females comprised 45 (37.2%) of the

study population. Diabetes mellitus was prevalent in 15 cases (12.5%). Diabetics had worse

postoperative BCVA compared to non-diabetics (p=0.036). Furthermore, diabetic patients had

lesser K1 and K2 compared to non-diabetics (p<0.001. The mean BCVA preoperatively was 5/60 ± 3 lines, compared to a mean BCVA 6 months postoperatively of 6/9 ± 2 lines on Snellen’s chart,

with a mean improvement in BCVA of 5.87 ± 2.78 lines. Postoperative BCVA was 6/9 or better in

56.7%, 6/12 or better in 75.8% and 6/18 or better in 89.2% of the cases.Presence of astigmatism had no significant correlation with postoperative BCVA (p=0.257). The mean spherical equivalent

postoperatively was -0.80 ± 1.50 D. CONCLUSION: It can be anticipated that in the near future,

phacoemulsification will be the main cataract surgical procedure in Sudan in view of the better visual outcome and the patient’s satisfaction compared to the classical extracaspular cataract

surgery.

Keywords: Phacoemulsification; cataract; Visual outcome.

INTRODUCTION Cataract is the leading cause of blindness

world-wide as well as in Sudan. Due to the

environmental features of sub-Saharan Africa and poor Savannah regions, cataract

represents 60% of all cases of blindness in

the region.1 Cataract, with all its types, is

present in all regions of Sudan. The total number of cataract surgeries in year 2001

was 28,500 nation-wide. However, Only 55%

of those had intraocular lens implanted. Cataract surgical rate was estimated to be

950/million population/year.1

Likewise rest of the countries in the region, phacoemulsification is a new surgical

technique that was, until recently, not

performed in the region.2 Majority of cases

during the above period were extracapsular cataract surgeries. Phacoemulsification was

first done in Sudan in year 2001.1 Despite its


impact on modern cataract surgery in the

region, the visual outcome of this technique among African population was not reported

in the literature.

This study aims to evaluate the visual

outcome of the first 120 phacoemulsification surgeries done in Walidain Charity Eye

hospital, Sudan.


The first 120 consecutive patients who

underwent phacoemulsification in Walidain Charity Eye hospital, Omdurman, Sudan

were retrospectively studied to evaluate the

visual outcome postoperatively. Records

were traced at the statistical department of the hospital, and data identified were collected.

Incomplete records were excluded.

Demographic data, best-corrected preoperative visual acuity, keratometry

readings, axial length, best corrected

postoperative visual acuity and postoperative refraction at 6 months were the main

variables studied. Visual acuity was checked

pre- and post-operatively using Snellen‟s E

Chart. Keratometry was done preoperatively

using Shin-Nippon Accuref-K 9001 Autoref-

Keratometer. Axial length was calculated using Nidek Echoscan US-800 A-scan

ultrasound. Visual acuity and refraction were

assessed 6 months after surgery. Data

analysis was done using SPSS version 13.0. Descriptive and bivariate correlational

analyses were the main statistical tests used.

The p value < 0.05 was considered as significant.

RESULTS

The study included 120 patients. The mean

age was 61.1 ± 10.58 years. Females

comprised 45 (37.2%) of the study population as compared to 75 males (62.5%).

Diabetes mellitus was prevalent in 15 cases

(12.5%). Among the study sample, the presence of diabetes mellitus was associated

with worse postoperative best corrected

visual acuity (p=0.036). Furthermore, those with diabetes mellitus were found to have

flatter corneas (Figure 1) preoperatively

compared to non-diabetics (lesser K1 and K2

readings “p<0.001”).

Figure 1: Box-plot showing the correlation between presence of diabetes and the keratometry readings (K1 and K2) which indicates flatter cornea in diabetics compared to non-diabetics

Visual outcome of Phacoemulsification

83

The mean best corrected visual acuity

preoperatively was 5/60 ± 3 lines, compared to a mean best corrected visual acuity 6

months postoperatively of 6/9 ± 2 lines on

Snellen‟s chart, with a mean improvement in

visual acuity of 5.87 ± 2.78 lines postoperatively as compared to preoperative

measures. Best corrected postoperative visual

acuity was 6/9 or better in 56.7%, 6/12 or better in 75.8% and 6/18 or better in 89.2%

of the cases. Presence of astigmatism had no

significant correlation with postoperative BCVA (p=0.257). Among study population

there was no significant difference between

males and females in terms of postoperative

BCVA (p=0.661). Older patients among study population had

their left eye operated more frequently than

younger patients (p=0.018). This is probably because the right eye had already been

operated previously in most of old-age

patients. On the other hand, younger patients

had better best corrected postoperative visual acuity (Figure 2 and Figure 3) compared to

older patients (p=0.007). This may be due to

the possibility of other co-existing

pathologies (such as age related macular degeneration) in old patients.

The mean spherical equivalent

postoperatively was -0.80 ± 1.50 D. Females had higher spherical power and spherical

equivalent in postoperative refraction as

compared to males (p=0.019, p=0.015 respectively).

Left eye had higher cylindrical refraction

postoperatively as compared to right eye

(p=0.046). Postoperative BCVA had strong positive correlation with preoperative BCVA

(p<0.001).

There were no postoperative complications noted in all patients at the end of the 6-

months follow-up period.

Figure 2: A bar-chart showing the distribution of preoperative BCVA among different age groups.



Figure 3: A bar-chart showing the distribution of postoperative BCVA among different age groups.

DISCUSSION

Visual outcome of phacoemulsification was well studied and reported in the European

and American literature,3,4

yet, this was not

the case in Africa. Although the application of phacoemulsification procedure has been

started at the beginning of this century in

most of the countries in the region, no reports were published in pubmed on its outcome so

far.

In this study, diabetes mellitus was found to

directly affect the visual outcome of phacoemulsification. This finding is

consistent with the results of a previous study

done by Mozaffarieh et al in Austria in 2005.5

We also found that diabetics had lesser

keratometry reading as compared to non-

diabetics. Touzeau et al,6 however, found no

significant correlation between these two

parameters.

Best corrected visual acuity postoperatively

was better than 6/12 in 75.8% of patients in

the study. Although this is lesser than

European standards (6/12 or better in 86-90%)

3, it is considered acceptable for the first

120 cases performed. Compared to results

from Yemen (6/18 or better in 85.3%).7 Our

study showed better visual outcome (6/18 or

better in 89.2%).

In this study, no significant correlation was found between gender and postoperative best

corrected visual acuity. This is similar to

results of Lundqvist et al,8 Who found no

significant difference between males and females in terms of postoperative best

corrected visual acuity.

We found that cylindrical power postoperatively was higher in left eye

compared to right eye. This can be attributed

to the more phaco probe handling in the left eye in right-handed surgeons due the nose

anatomical position.

In our study better preoperative visual acuity

was associated with a significantly better


85

postoperative visual acuity. Hence, it is

recommended, in phacoemulsification, to go for surgery earlier, and not to wait until

cataract is hard enough to cause to

intraoperative and postoperative

complications. Currently, more eye surgeons are shifting to

phacoemulsification. It can be anticipated

that in the near future, phacoemulsification will be the main cataract surgical procedure

in Sudan in view of the better visual outcome

and the patient satisfaction compared to the classical extracaspular cataract surgery.

References 1. National plan for eye care in Sudan – A five-year

plan (2003 – 2007). Report by National Programme for Prevention of Blindness, Ministry of Health, Khartoum, Sudan, 2002.

2. Kaimbo wa Kaimbo D. Comparative study of

extracapsular and intracapsular cataract extraction

in Kinshasa (zaire) [Article in French]. Bull Soc Belge Ophtalmol. 1993;249:81-87

3. Slavíková A, Novák J, Krejzková T. European cataract outcome study--evaluation of 3 years in European study [Article in Czech]. Cesk Slov

Oftalmol. 2009;65:49-52. 4. Salomão SR, Soares FS, Berezovsky A, et al.

Prevalence and Outcomes of Cataract Surgery in Brazil: The São Paulo Eye Study. Am J Ophthalmol. 2009 Apr 29. [Epub ahead of print]

5. Mozaffarieh M, Heinzl H, Sacu S, et al. Clinical outcomes of phacoemulsification cataract surgery in diabetes patients: visual function (VF-14), visual

acuity and patient satisfaction. Acta Ophthalmol Scand. 2005;83:176-83.

6. Touzeau O, Levet L, Borderie V, et al. Anterior segment of the eye and diabetes mellitus [Article in French]. J Fr Ophtalmol. 2004;27:859-70.

7. Hameed AS, Alkhatib TK, Rageh MA, et al. Yemeni experience with phacoemulsification. Saudi Med J. 2009;30:687-92.

8. Lundqvist B, Mönestam E. Gender-related differences in cataract surgery outcome: a 5-year follow-up. Acta Ophthalmol. 2008;86:543-8.



ORIGINAL ARTICLE

Chemical injuries of the eye – Clinical study of 40 cases S C Reddy, P R Reddy

Department of Ophthalmology, Osmania Medical College. Hyderabad, Andhra Pradesh, India

Correspondence to: Prof. Dr. S. C. Reddy. Dept. of Ophthalmology, UCSI School of Medicine, Bukit Khor,

mukim Rusila, 21600 Marang, Teremgganu, Malaysia. Email: [email protected]. Tel No: +6013-

6244532. Fax No: +609-6281885

Abstract AIM: To determine the type of chemical causing eye injury, occupation of patients, severity of

ocular injury, complications and visual outcome in patients who sustained chemical injuries of eye.

METHODS: Gender, age, occupation, nature of chemical, eye involved, vision at admission, severity of ocular injury, complications and visual outcome were noted from the case records of

patients who were treated for chemical injuries of eye over a period of one year. RESULTS: A total

number of 40 patients (53 eyes) were treated, of which 33 were males and 7 were females. There

were 13 patients with both eyes involved while 27 had one eye involvement. Industrial workers (32.5%) were the most commonly affected people. Injuries due to alkalis were more common than

acids. The vision at presentation was poor (< 6/60) in 43.4% of eyes. In majority of the patients

(73.6%) the severity of chemical injury was mild to moderate. Corneal opacity (45.2%) was the most common complication. Best corrected vision of 6/12 or better was achieved in 22.6% of eyes.

CONCLUSION: Public education and practice of protective measures for eyes at the work site will

help in reducing the severity of ocular injury due to chemicals. Thorough irrigation of eyes and appropriate immediate treatment will reduce the long term complications and sequelae in these

patients.

Keywords: Chemical injury of eye, acids, alkalies, complications..

INTRODUCTION Chemical injuries are potentially devastating

ocular surface injuries that can result in

permanent visual impairment or blindness. Acid injuries tend to remain confined to the

ocular surface and produce more superficial

damage, while alkalis penetrate easily into the eye and cause damage to the corneal

stroma, endothelium as well as other anterior

segment structures.1 Most victims of

chemical injuries are young with exposure occurring in industrial accidents, at home and

in personal assaults. Alkali injuries tend to

occur more commonly than acid injuries.2,3

Among the large number of reports available

from Western countries on chemical injuries

of eye in the Pubmed search, only few are from India.

4-8 Therefore, the present study

was undertaken to determine the

demographic and clinical profile,

87

complications and visual outcome of

chemical injuries in patients treated in a tertiary government eye hospital.


The case records of all patients treated for chemical injuries of eye in Sarojini Devi Eye

Hospital, Osmania Medical College,

Hyderabad, Andhra Pradesh state, India, over a period of one year, were reviewed. Gender,

age, occupation of patients, nature of

chemical causing eye injury, visual acuity at admission, severity of ocular injury,

complications and visual outcome following

treatment were noted from the patients‟

records. When the patient was not sure about the type of chemical fallen into the eyes, its

nature was decided as acid or alkali based on

the litmus paper test which indicates the pH of tears. The chemical injuries were graded

according to Roper-Hall modification of the

Hughes classification system.9 All the patients were treated on the standard protocol

for chemical injury which included

immediate continuous irrigation of the eye

with normal saline until the pH of tears come to near neutral level, removal of foreign

particles from the eye, topical

dexamethasone, ciprofloxacin, homatropine, artificial tears, oral vitamin C, and oral

doxicycline. Timolol eye drops and Tab.

Acetazolamide were given whenever there

was increased intraocular pressure. Paching of the eye was done depending on the size of

corneal epithelial defect. Bandage soft

contact lens usage/tarsorrhaphy were done in eyes with persistent epithelial defect. The

complications during the follow up period

and visual outcome at the last follow up were noted. The results were analyzed using epi-

info programme.

RESULTS A total number of 40 patients (53 eyes) were

treated, of which 33 were males and 7 were

females. There were 13 patients with both eyes involved while 27 had one eye

involvement. The age of patients ranged from

8 years to 50 years; 5 were children below the age of 12 years. Majority of patients

(60%) were in the age group of 21-40 years.

More than half of the patients (23 out of 40,

57.5%) sustained injuries in factories, laboratories and/or workshops (Table 1).

Table 1: Occupation of the patients with chemical injuries of eye (n=40)

Occupation Number Percentage

Industrial worker 13 32.5% Pharmacy lab worker 8 20.0% Workshop mechanic 2 5.0% Student 7 17.5% Businessman 4 10.0% Housewife 3 7.5% Labourer 2 5.0%

Gold-smith 1 2.5%

The chemicals causing ocular injury were

alkalies (18), acids (16) and others (6);

the most common chemical being

hydrochloric acid (Table 2).

Table 2: Nature of chemicals causing ocular injury (n=40)

Nature of chemical Number Percentage

Alkalies Ammonia 5 12.5% Clacium hydroxide (Lime, cement)

8 20.0%

Sodium hydroxide

5 12.5%

Acid Hydrochloric acid 11 27.5% Sulphuric acid 4 10.0% Citric acid

1 2.5%

Others Dimethyl sulphate 2 5.0%

Dimethyl benzene 2 5.0% Copper sulphate 1 2.5% Sodium silicate 1 2.5%

Twenty patients (50%) came to the eye

hospital within 2 hours of the chemical injury to the eye; 10 patients (25%) came within 12

hours; 6 patients (15%) came within 24

hours; while 4 patients (10%) came after 24 hours. The probable delay in coming to the

hospital could be due to far distance from the

place of chemical injury and transportation time to come to the hospital. However, all the

patients gave history that their eyes were

washed with water immediately after the

chemical falling in the eyes. The visual acuity at admission ranged from

no perception of light (NPL) to 6/6. The

Chemical injuries of the eye


vision was poor (< 6/60) in 23out of 53

(43.4%) eyes (Table 3). Table 3: Visual acuity at admission (n=53 eyes)

Visual acuity Number Percentage

6/6 4 7.5% 6/9 – 6/12 10 18.9% 6/18 – 6/24 8 15.1% 6/36 – 6/60 8 15.1% CF 5M – CF 1M 14 26.4%

HM 5 9.4% PL 3 5.6% NPL 1 1.9%

CF= counting fingers; HM= hand movements; PL= perception of light; NPL= no perception of light.

In majority of the patients (73.6%) the chemical injury was mild to moderate in

severity (Table 4). The grading of chemical

injuries 9 was as follows: grade I – corneal epithelial defect, iris details seen, no limbal

ischemia; grade II – hazy cornea but visible

iris details, <1/3 limbal ischemia; grade III –

total loss of corneal epithelium, stroma hazy obscuring iris details, 1/3 to 1/2 limbal

ischemia; grade IV – opaque cornea

obscuring the view of iris, >1/2 limbal ischemia.

Table 4: Severity (grading) of chemical injuries (n=53 eyes)

Grading Number Percentage

Grade I 18 34.0% Grade II 21 39.6% Grade III 6 11.3% Grade IV 8 15.1%

In 18 out of 40 patients (45%), other parts of

the body were also affected --- face, neck and

chest in 5 cases, face in 9 cases, forehead in 2 cases and spillage on the body in 2 cases.

Since the vision was good after treatment

many patients did not come for follow up for longer period. The follow up period ranged

from 2 weeks to 6 months. Cornea was clear

in 13 eyes. Corneal opacity (45.2%) was the most common complication in our study

(Table 5). More than one complication was

present in some eyes.

Table 5: Complications of chemical injuries (n=53 eyes)

Complication Number Percentage

Macular corneal opacity 21 39.6% Total corneal opacity 3 5.6% Punctate corneal opacities 4 7.5% Neovascularization of the cornea

12 22.6%

Perforation of the cornea 2 3.7% Iridocyclitis 5 9.4% Secondary glaucoma 4 7.5%

The best corrected vision of 6/12 or better

was achieved in 22.6% of eyes (Table 6).

Vision was poor (<6/60) in 24.5% of eyes.

Table 6: Best corrected visual acuity at last follow up of the patient (n=53 eyes)

Visual acuity Number Percentage

6/6 4 7.5% 6/9 – 6/12 8 15.1% 6/18 – 6/24 18 34.0% 6/36 – 6/60 10 18.9% CF 2M 3 5.6% HM 4 7.5% PL 2 3.8% NPL 4 7.5%

CF= counting fingers; HM= hand movements; PL= perception of light; NPL= no perception of light.

DISCUSSION

Factories are the most common place for the

occurrence of chemical injuries of eyes; and

the chemicals (acids and alkalis) fall in the eyes of workers due to spillage from the

containers while they are being transferred

from one container to the other, or during their transportation. The other modes of

sustaining chemical injuries include

construction site accidents (cement, mortar), domestic accidents (floor cleaning solutions,

solvents, paints, vinegar), agriculture

accidents (insecticides, fertilizers), laboratory

accidents (various reagents), mechanic workshop accidents (battery water),

deliberate personal assaults with

acids/alkalis. Various chemicals10

causing ocular injuries are summarized in Table 7.


89

Table 7: Common alkalis and acids causing ocular injury

Chemicals Common sources and uses

Alkalies Ammonia (NH3) fertilizers, refrigerants, cleaning agents (7%) Lye (NaOH) drain cleaners Potassium hydroxide (KOH) caustic potash Lime (CaOH2)

plaster, mortar, cement, whitewash

Acids

Sulfuric acid (H2SO4) industrial cleaner, battery acid Sulfurous acid (H2SO3) fruit and vegetable preservative, bleach, refrigerant Hydrofluoric acid (HF) glass polishing, glass frosting, mineral refining, gasoline alkylation, silicon

production Acetic acid (CH3COOH) vinegar (4-10%), essence of vinegar (80%), glacial acetic acid (90%) Chromic acid (Cr2O3) used in chromic plate industry Hydrochloric acid (HCl) Used as 32 – 38% solution

The frequency of chemical injuries in any

study depends on the number and variety of

industries present around the treating hospital, protective/preventive measures

practiced at the work site, and medical

facilities available around the site of accident. In the present study, males outnumbered the

females (4.5:1) which was similar to the

studies reported in the literature.2,3,7

Factory workers were more commonly involved

(32.5%) when compared to other

occupations. Kuckelkorn et al11

from

Germany reported 73.8% industrial accidents in their retrospective study of severe alkali

burns of the eyes. The occurrence of

domestic accidental chemical injuries in our study was 7.5% which is much lower than the

same reported from France12

(23%) and

Germany3 (37%).

Immediate irrigation of the eyes following

chemical injury is a very important step in the

management of these cases. Lesser extent of

ocular damage, better visual outcome and short duration of hospital stay has been

reported in patients treated with immediate

copious irrigation with tap water.13

In our series, grade III and IV injuries were noted in

14 out of 53 eyes (26.4%) which is less than

the percentage of the same reported from

Australia14

(27.6%) and one of the studies from India

7 (35.9%). The general observation

is that such severe injuries are more common

in personal assaults because the victim‟s face including the eyes are targeted usually in

such cases.15

The ultimate visual prognosis in chemical

injuries depends on the degree of severity of

the injury at initial presentation. In our study, the best corrected visual acuity at the last

follow up was 6/12 or better in 22.6% of

eyes, while the same vision was achieved in 76% of eyes in the study reported by Saini

and Sharma.7 Blindness (vision CF2M –

NPL) was noted in 24.4% of the eyes in our series, which is much lower than 57.4%

reported from China.16

The medical management of severe chemical

injuries of eye must be directed towards (1) promoting ocular surface epithelial recovery

and trans-differentiation with use of tear

substitutes, ointment at bed time, patching the eye, bandage soft contact lens, fibronectin,

epidermal growth factor, retinoic acid, and

viscoelastics; (2) augumenting corneal repair by supporting keratocyte collagen production

and minimizing ulceration related to

collagenase activity by using topical and

systemic ascorbate, tetracycline, and collagenase inhibitors; and (3) control of

inflammation with use of topical

corticosteroids, medroxyprogesteron 1%, nonsteroidal anti-inflammatory drugs,

andcitrate.17,18

In order to promote epithelial

wound healing, limbal stem cells

transplanataion19

, conjunctival transplantation

20, amniotic membrane

transplantation21

are performed in patients

with chemical injuries of eye. When the corneal opacity is developed, penetrating

keratoplasty for visual rehabilitation is done.



The prognosis of its success depends on the

original severity of the ocular injury and its sequelae after the initial treatment such as

uncontrolled glaucoma, hypotony, anterior

chamber membrane formation and retinal

detachment.22

Keratoprosthesis procedure offers useful vision in hopeless bilateral

corneal blindness patients due to chemical

injuries, with good optic nerve and retinal function.

23

CONCLUSION Chemical injuries of the eyes are more

common in industrial workers. Public

education and practice of protective measures

for the eyes at the work site will help in reducing the severity of ocular injury due to

chemicals. Thorough irrigation of eyes at the

scene of accident and at hospital, and appropriate immediate treatment of severe

cases will reduce the long term complications

and visual impairment in these patients.

References 1. Wagoner MD, Kenyon KR. Chemical injuries of

eye. In: Albert DM, Jakobiec FE (eds). Principles and practice of Ophthalmology, Vol 2, 2nd ed, Philadelphia, WB Saunders Company. 2000; pp 943-59.

2. Morgan SJ. Chemical burns of the eye: causes and

management. Br J Ophthalmol 1987; 71:854-7. 3. Kuckelkorn R, Luft I, Kottek AA et al. Chemical

and thermal eye burns in residential area of RWTH Aachen: analysis of accidents in 1 year using a new automated documentation of findings. Kin Monatsbl Augenheilkd 1993; 203:39-42. (article in German)

4. Raizada JK, Dwivedi PC. Acute ocular lesions in Bhopal gas tragedy. Indian J Ophthalmol 1986;

34:324-7. 5. Maskati QB. Ophthalmic survey of Bhopal victims

– 100 days after the tragedy. Indian J ophthalmol 1986; 34:328-31.

6. Dada T, Sharma N, Kumar A. Chemical injury due to colours used at the festival of Holi. Natl Med J India 1997; 10: 256.

7. Saini JS, Sharma A. Ocular chemical burns –

Clinical and demographic profile. Burns 1993; 19:67-9.

8. Agarwal T, Vajpayee RB, Sharma N, Tandon R. Severe ocular injury resulting from chuna packets. Ophthalmology 2006; 113:961.

9. Roper-Hall MJ. Thermal and chemical burns. Trans ophthalmol Soc UK 1965; 85:631-53.

10. McCulley JP. Chemical injuries. In:Smolin g, Thoft RA (eds). The Cornea: Scientific Foundations and Clinical practice, 2nd ed. Boston, Little Brown 1987; pp 527-42.

11. Kuckelkorn R, Makropoulous W, Kottek a, Reim M. retrospective study of severe alkali burns of the eyes. Klin Monatsbl Augenheilkd 1993; 203: 397-402.9article in German)

12. Merle H, Donnio A, Ayeboua l, et al. Alkali ocular burns in Martinique (French West Indies) : evalauationof the use of an atmospheric solution as the rinsing product. Burns 2005; 31: 205-11.

13. Ikeda N, Hayasaka Y, Watanabe K. Alkali burns of the eye; effect of immediate copious irrigation with tap water on their severity. Ophthalmologica 2006; 220:225-8.

14. Brodovsky SC, Mccarty CA, Snibson G, et al. management of alkali burns: an 11 year retrospective review. Ophthalmology 200; 107: 1829-35.

15. Beare JD. Eye injuries from assault with chemicals. Br J Ophthalmol 1990; 74: 514-8.

16. Li GH. Clinical analysis of 107 cases with chemical burns. Zhonghua Zheng Xing Shao shang wai Ke

Za zhi 1990; 6; 34-35,76. (article in Chinese) 17. Wagoner MD. Chemical injuries of the ye. Surv

Ophthalmol 1997; 41: 275-313. 18. Kenyon KR. Decision making in the therapy of

external eye diseases: noninfected corneal ulcers. Ophthalmology 1982; 89: 44-51

19. Kenyon KR, Tseng SCG. Limbal autograft transplantation for ocular surface disorders. Ophthalmology 1989; 96: 709-22.

20. Thoft RA. Conjunctival transplantation. Arch ophthalmol 1977; 95: 1425-7.

21. Prabhasawat P, Tesavibul N, Prakairungthong N, Booranapong W. Efficacy of amniotic membrane patching for acute chemical and thermal ocular burns. J Med Assoc Thai 2007; 90: 319-26.

22. Brown SI, Bloomfield SE, Pearce DB. A follow-up report on transplantation of the alkali-burned

cornea. Am J Ophthalmol 1974; 77: 538-42. 23. Falcinelli G, Falsini B, Taloni M, et al. Modified

osteo-odonto-keratoprosthesis for treatment of corneal blindness: long term anatomical and functional outcomes of 118 cases. Arch Ophthalmol 2005; 123: 1319-29.


91

CASE REPORT

Unilateral Isolated Ocular Tuberculosis with no

systemic involvement

U T Chan , M M Choo , S C Reddy

Ophthalmology department, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia

Correspondence to: Dr.Chan U Teng. Dept. of Ophthalmology, Hospital Sultanah Nur Zahirah, Jalan Sultan Mahmud 20400 Kuala Terengganu, Terengganu, Malaysia. Email: [email protected], Tel No: +6012-9807009

Abstract

A case of tuberculous anterior uveitis in a 42 years old lady is reported. She presented with typical

signs of anterior uveitis in the left eye. There was no systemic tuberculosis in the body. The diagnosis was based on eye signs, raised ESR, positive tuberculin test and positive response to

isoniazid test. She regained normal vision with antituberculous treatment. This case highlights that

ocular tuberculosis may occur in the absence of systemic disease; early diagnosis and prompt

treatment may prevent ocular morbidity and blindness.

Keywords: Ocular Tuberculosis; Uveitis; Granulomatous; Koeppe nodule.

INTRODUCTION Ocular tuberculosis can manifest a myriad of

clinical presentation and the definitive

diagnosis can be daunting due to the

difficulty of getting ocular samples for microbiologic or histologic evaluation.

Granulomatous anterior uveitis may be a

primary manifestation of ocular tuberculosis. The disease may also present with severe

non-granulomatous anterior uveitis. Uveitis

may be acute relapsing, or chronic and

persistant. Tubercles may be seen on the iris, and more commonly in the choroid with

associated focal choroiditis.1 In a case

records study of 8759 cases of uveitis, Rathinam and Namperumalsamy

2 reported

that tuberculosis was found to be the cause in

5.6% of all types of uveitis (anterior, intermediate, posterior, diffuse).; and in 4%

of 5028 anterior uveitis patients. They

reviewed the pattern of uveitis of 15221 cases

reported from several countries over 35 years and found that tuberculosis comprised

between 0.2% and 10.5% as aetiology of uveitis. Literature search did not show any

data on the aetiology of uveitis in Malaysia.

We report a case of tuberculous anterior

uveitis, the diagnosis of which was based on typical signs of anterior uveitis, absence of

systemic tuberculosis in the body, raised

ESR, positive tuberculin test and positive response to isoniazid test.

CASE REPORT

A 42 years old Chinese lady presented to our eye clinic on 1/6/2005 with the complaints of

blurring of vision and redness of the left eye

for the past 2 months with worsening of condition over the past 3 weeks. She had no

history of chronic cough or fever, no

significant past medical history and no family history of tuberculosis. She was not on

immunosuppressive therapy. She saw a

general practitioner who gave eye drops with

no improvement.


Ocular examination of the left eye showed a

visual acuity of 6/60, not improving with pinhole. There was circumcorneal injection.

Slit lamp examintion showed mutton fat

keratic precitpitates on the inferior half of the

corneal endothelium; +++ cells in the anterior chamber. A Koeppe nodule was noted

between 5 and 6 o‟clock position, and

posterior synechiae at 8 o‟clock (Figure 1).

Figure 1: showing Koeppe nodule between 5 and 6 o'clock position (white arrow) and posterior synechiae at 8 o'clock position (yellow arrow) in the left eye.

There was no hypopyon or rubeosis irides.

Intraocular pressure was 16 mm Hg. Fundus

examination revealed vitreous condensations. However, there was no evidence of active

vitritis. The optic disc was pink with a cup-

disc ratio of 0.3 and the retina was normal.

There was no perivascular sheathing or choroidal tubercle.

Examination of the right eye was normal,

with a 6/6 visual acuity. Intraocular pressure was 16 mmHg ; anterior and posterior

segments were normal.

Examination of the respiratory system

showed clear lungs with no palpable regional lymph nodes. The rest of systemic

examination was unremarkable.

A provisional diagnosis of anterior granulomatous uveitis was made. Gutt

dexamethasone 0.1% four hourly and gutt

homatropine 2% tds were started for the left eye. Blood investigations were carried out for

full blood count, renal profile, erythrocyte

sedimentation rate, connective tissue disease

screening, toxoplasma specific IgG and IgM,

VDRL, sputum for acid-fast bacilli and

Mantoux test. A chest radiograph was also done.

The patient was reviewed one week later.

Visual acuity of the left eye had improved to

6/18. Keratic precipitates were less in the size. The inflammatory reaction in the

anterior chamber was less (++ cells). Pupil

was irregular and dilated. All blood investigations were normal except raised

erythrocyte sedimentation rate (32mm/hour).

The Mantoux test was strongly positive with a blister measuring 25mm. The chest

radiograph was normal. A diagnosis of ocular

tuberculosis in the left eye was made and the

patient was started on anti-tuberculosis therapy which consisted of ethambutol

800mg once daily, isoniazid 300mg once

daily, rifampicin 600 mg once daily, pyrazinamide 1000 mg once daily and

pyridoxine 10 mg once daily.

On a review 2 weeks later, the visual acuity of the left eye had further improved to 6/12

and the anterior segment findings remained

the same. However, she developed vitritis

(+++ cells) with a hazy fundus view. Anti-tuberculosis therapy and topical steroids were

continued. Two weeks later, visual acuity of

the left eye had improved to 6/9 and the vitritis had reduced (+ cells). There was no

retinal vasculitis or choroidal tubercle.

On three successive follow up visits to the

clinic at two-weeks interval, the inflammatory cells in the anterior chamber

had reduced to occasional cells and there

were no cells in the vitreous; the topical steroids were reduced to a qid for 2 weeks,

tds for 2 weeks, bd for 2 weeks and od for 2

weeks in left eye; and then stopped. The intraocular pressure was 17-19 mm Hg

during the follow up period. On completion

of the 3-month intensive regime of the anti-

tuberculosis treatment, the visual acuity of the left eye was 6/12 with quiet anterior and

posterior segments. The left fundus was

normal. The intensive anti-tuberculosis treatment regime was subsequently switched

to a maintenance regime consisting of

isoniazid 300 mg daily and rifampicin 600 mg daily for six months. On the completion

of the regime, the visual acuity of the left eye

Ocular Tuberculosis

93

had improved to 6/6. The anterior and

posterior segments of the left eye were quiet. The intraocular pressure in left eye was

normal (18 mm Hg). The left eye remained

quiescent with a visual acuity of 6/6 on the

subsequent follow-up sessions in the next three months. The right eye remained

unaffected throughout the course of the

disease.

DISCUSSION

Endogenous Tuberculosis is a curable disease and it is one of the major causes of morbidity

and mortality worldwide. It is estimated to

affect 1.86 billion individuals with 8 million

new cases and 1.87 million deaths annually in the world.

3 Ocular tuberculosis is relatively

rare, comprising of 1% of all cases of

tuberculosis.4 It is often a result of

haematogenous spread or hypersensitivity

reaction to the Mycobacterium tuberculosis

antigen from a distant foci in the absence of any infectious agent in the eye.

Tuberculosis may affect any part of the eye,

the most common site being the choroid

because of its high level of blood supply and oxygenation. The infection may be primary

or secondary in nature. There is no systemic

lesion in primary ocular tuberculosis and the infection is usually restricted to the

conjunctiva and cornea and may present as an

ulcer, a tumour mass, phlyctenulosis or

interstitial keratitis. In secondary tuberculosis, the infection occurs as a result

of local spread from an adjacent structure or

haematogenous spread, mainly from the lungs.

5 Ocular tuberculosis is frequently

unilateral or asymmetric. The most common

manifestation is choroiditis followed by anterior uveitis and sclerokeratitis.

6 Ocular

tuberculosis may masquerade as ocular

neoplasm.7

Our patient presented with granulomatous anterior uveitis with the characteristic mutton

fat kerato-precipitates, iris nodules and

posterior synechiae but there was no choroidal involvement throughout the course

of the disease.

The definitive diagnosis of tuberculosis

requires a positive culture of Mycobacterium

tuberculosis from tissue samples. Ocular

tuberculosis is often difficult to diagnose owing to its similar clinical features of other

causes of uveitis, the invasiveness of

obtaining tissue samples and the limitations

of the available diagnostic tests. An initial work-up with negative results should not

eliminate tuberculosis from the differential

diagnosis. A thorough history and a complete physical examination are mandatory in

addition to the investigations. Sputum for

acid-fast bacilli is carried out to diagnose pulmonary tuberculosis as this method

detects the infectious cases of tuberculosis

and it is highly specific and inexpensive and

this was negative in this patient. Mantoux skin testing with purified protein

derivative of tuberculin is a widely used test

for screening but it is of limited value in the diagnosis because false negative reaction is

found in immunosuppressed patients and

false positive is observed in individuals vaccinated with bacilli Calmette-Guerin.

8 It

has been postulated that hypersensitivity to

mycobacterial antigens plays a role in the

pathogenesis of anterior uveitis.9 Mantoux

test was strongly positive in our patient with

a blister measuring 25 mm.

Polymerase chain reaction is a recent rapid diagnostic technique in which the

mycobacterial DNA is amplified and detected

with high sensitivity and specificity. This test

is of paramount importance in diagnosing primary ocular tuberculosis as only a small

amount of aqueous humour is needed.10

The detection of anti-cord factor antibody via enzyme-linked immunosorbent assay

(ELISA) is another new diagnostic method.

Cord factor (trehalose-6, 6‟dimycolate) is the most characteristic cell wall component of

the tubercle bacilli and the detection of

antibodies against the cord factor antigen

supports the diagnosis of tuberculosis.11

The isoniazid therapeutic trial, also known as

Schlagel test consists of a course of isoniazid

of 300 mg daily for 3 weeks. A positive test consists of a dramatic improvement in 1 to 3

weeks of treatment.12

The treatment of ocular tuberculosis is aimed at the infection and the inflammatory

reaction. Primary treatment for ocular

Ocular Tuberculosis


tuberculosis should be systemic with a multi-

drug combination because pulmonary or other foci of infection may coexist. Multi-

drug therapy also avoids mycobacteria

resistance. An initial clinical response usually

occurs in 2 weeks.5 The American Thoracic

Society recommends a 2-month initial phase

of isoniazid, rifamipicin and pyrazinamide

followed by a 4-month maintenance phase of isoniazid and rifampicin.

13 The regime of this

patient differed (a 3-month initial phase and a

4-month maintenance phase) as it is tailored to this patient‟s clinical response.

Collaboration with the physician in the

management should be established to monitor

for the systemic toxic effects of the drugs. Ocular tuberculosis may occur in the absence

of systemic disease. The disease may mimic

several clinical entities. Early diagnosis and prompt treatment may prevent ocular

morbidity and blindness.

References 1. Massaro D, Katz S, Sachs M. Choroidal tubercles: a

clue to haematogenous tuberculosis. Ann Inten Med 1964; 60:231-41.

2. Rathinam SR, Namperumalsamy P. Global variation and pattern changes in epidemiology of uveitis. Indian J Ophthalmol 2007; 55:173-83.

3. Dye C, Schlee S, Dolin,P, Pathania V, Raviglione MC ; for the WHO Global Surveillance and

Monitoring Project. Global burden of tuberculosis:

estimated incidence, prevalence, and mortality by country. JAMA. 1999; 282:677-86.

4. Bouza E, Merino P, Munoz P. ocular tuberculosis. A prospective study in a general hospital. Medicine (Baltimore) 1997; 76:53-61.

5. Sheu SJ, Shyu JS, Chen LM, Chen YY, Chirn SC, Wang JS. Ocular manifestations of tuberculosis. Ophthalmology 2001; 108:1580-5.

6. Knox DL: syphilis and tuberculosis, in Ryan SJ (ed): Retina. St Louis, CV Mosby CO, 1989: 647-54.

7. Demirci H, Shields CL, Shields JA, Eagle RC. Oculat tuberculosis masquerading as ocular

tumours. Surv Ophthalmol 2004; 49:78-89. 8. Raviglione MC, O‟Brien RJ. Tuberculosis in

FauciAS, Braunwaid E, Isselbacher KJ: Harrison‟s Principle of Internal Medicine, 14th ed, New York, McGraw Hill, 1998;1004-14.

9. Kapoor AK, Gopal R, Lal B. Detection of anti-PPD IgG antibody and PPD-induced delayed type hypersensitivity in anterior uveitis patients. Indian J

Pathol Microbiol 1997; 40:303-7. 10. Arora SK, Gupta V, Gupta A, Bambery P, Kapoor

GS, Sehgel S. Diagnostic efficacy of polymerase chain reaction in granulomatous uveitis. Tubercle and Lung Disease 1999; 79:229-33.

11. Sakai J, Matsuzawa S, Usui M, Yano I. New diagnostic approach for ocular tuberculosis by ELISA using the cord factor as antigen. British J

Ophthalmol 2001; 85: 130-3. 12. Thompson MJ, Albert DM. Ocular tuberculosis.

Arch of Ophthalmol 2006; 123(6):844-49. 13. American Thoracic Society. Control of tuberculosis

in the United States. Am Rev Respir Dis 1992; 146:1623-33.

Ocular Tuberculosis

95

LETTER TO EDITOR

Sudan Test (ST) for near vision test

Dear Editor:

I would like to convey my congratulations for the launching of SJO as a first professional journal of

ophthalmology in Sudan concerning promotion of eye care.

I have a comment on the article titled “Causes of low vision and visual outcome after using of low

vision devices in Sudanese children” page 37 of the first issue. In that article it was mentioned that

near vision was performed by Jaeger test (ST).However, Jaeger test is different than ST. Jaeger was the first and oldest test for near vision acuity and in many countries was replaced by other

more standard tests like Meter and Point systems. ST is an abbreviation of Sudan Test which was

recently developed in Sudan (2005). Standard log MAR was used for progression of its letter size,

and it becomes commonly used in all low vision work and many clinics in Sudan.

Thank you

Sincerely

Dr. Atif B Mohamed Ali, PhD


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