Katarak-Fridayana FK Untan

8/2/2019 Katarak-Fridayana FK Untan

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CATARACT


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Definition

A clouding that develops in thecrystalline lens of the eye or in itsenvelope (lens capsule), varying in

degree from slight to completeopacity and obstructing thepassage of light.


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Epidemiology

In 2002, the World HealthOrganization calculated thatthe number of visually

impaired people worldwidewas in excess of 161 million.

Cataract is the leading cause,

accounting for 47.8% of allcases


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Epidemiology (cont)Genetic

Recent developments in cataractepidemiology have identified a strong

genetic component. Increased or decreased gene

expression of a few groups of genes inthe lens epithelial cells may play animportant role in cataract formation.


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Epidemiology (cont)Nutrition, Health, Diabetes

A high body mass index in humans increases therisk of developing posterior subcapsular, nuclear,and cortical cataracts.

Diabetes is associated with cortical cataracts, as ishypertension.

These conditions can be treated but theeffectiveness of treatment on cataract progression is

unproven.


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Epidemiology (cont)Antioxidants

The role and mechanisms of action of antioxidant vitamins andminerals in the biochemistry and metabolism of the lens arenot clear.

Ascorbate, a water-soluble antioxidant, was not shown toreduce the incidence of cataract in most studies.

Vitamin E is a lipid-soluble antioxidant, which inhibits lipidperoxidation, stabilizes cell membranes, is affected byascorbate, and enhances glutathione recycling. Vitamin E hadno effect on cataract incidence in most studies.

Further longitudinal and intake studies are necessary toestablish the effect of nutrients on cataract.


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Epidemiology (cont)Sunlight and Irradiation

There is much evidence that UV-B light has an effecton cataractogenesis, presumably on the basis ofincreased oxidative damage.

Aging eyes are more susceptible to UV damagebecause the level of free UV filters decreases withage and breakdown products of the filters can alsoact as photosensitizers, which promote theproduction of reactive oxygen species and oxidation

of proteins. The risk of cortical and nuclear cataract has been

shown to be highest among those with high sunexposure at younger ages.


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Epidemiology (cont)Smoking and Alcohol

Smoking causes a three fold increase in the risk of developingnuclear cataracts.

There is limited evidence of an association between smoking

and posterior subcapsular cataract, and little or no associationwith cortical cataract.

Chronic alcoholism is associated with a significantly increasedrisk of cataract.Consumption of alcohol, particularly hardliquor and wine, is associated with nuclear opacities. Wine

drinking was inversely related to cortical opacity.

Some studies have not shown an association between alcoholconsumption and cataracts.


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Epidemiology (cont)Age, education, and other factors

Increasing age is the greatest risk factor for cataract due tocumulative exposure to risk factors together with an age-related decline in antioxidants and antioxidant enzymes.

Increasing age is also associated with an increased incidenceof diseases such as diabetes. The chronic cumulative effect oftaking medications (such as steroids) that may cause cataractsincreases the risk of developing cataracts in older people.

A higher level of education is associated with a lower risk of

age-related cataract; however, this may be related to smoking,alcohol intake, and increased sun exposure in people with lesseducation.


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Epidemiology (cont)Myopia

A third of the population over the age of 40 ismyopic, and cataract is the commonest cause ofvisual impairment in the elderly.

After controlling for age, gender, and other cataractrisk factors (diabetes, smoking, and education),posterior subcapsular cataracts were found to beassociated with myopia, deeper anterior chambers,

and longer vitreous chambers, suggesting that therefractive association with posterior subcapsularcataract is axial.


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Epidemiology (cont)Pharmacological Prevention of Cataract

Potential anticataract compounds includealdose reductase inhibitors, pantethine,

and aspirin-like drugs such as ibuprofen. New drugs are under investigation. An

anticataract agent would need to be safefor long-term use and sufficientlyinexpensive to compete with increasinglycost-effective cataract surgery.


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PATHOPHYSIOLOGY OFCATARACT


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The transparency of the lens isdependent on the regularorganization of the lens cells

and intracellular lens proteins.Genetic, metabolic, nutritional,and environmental insults and

ocular and systemic diseasescause cataracts by affecting lensclarity.


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Cell Proliferation andDifferentiation

Fibroblast growth factor (FGF) present in low concentrationsnear the anterior lens surface. stimulates epithelialproliferation

Higher concentrations near the lens equator inducedifferentiation into lens fibers. Other growth factors, such asepidermal growth factor (EGF), insulin-like growth factor(IGF), platelet-derived growth factor (PDGF), andtransforming growth factor (TGF-) are also involved in theseprocesses.

If the concentration of FGF is too low, the concentrations ofother growth factors are incorrect, or differentiation isinhibited by a cytokine, differentiation of epithelial cells intofiber cells in the equatorial zone will not occur.


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Metabolic Disturbance andOsmotic Regulation Failure The lens maintains ion differentials

between intra- and extracellularfluids (high potassium and lowsodium internally; low potassium

and high sodium externally) via theaction of the sodium-potassiumATPase pump.

Pump inactivation causes increasedintracellular osmolality, which with

membrane leakiness results inlocalized water accumulation andlight scatter.


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The lens epithelial cells are bathed in aqueoushumor, a source of nutrients and mineral ionsincluding calcium (Ca2+).

Ca2+ is a versatile intracellular signal that regulatesmany functions including the permeability of thecell membranes.

The extracellular Ca2+ concentration is 10 times theintracellular Ca2+ concentration, and this gradientdrives Ca2+ into the epithelial cell.

Ca2+ pumps on the plasma and intracellularorganelle membranes regulate cytoplasm Ca2+

levels. Within the cell, very little Ca2+ is free; most is bound

to complex proteins including crystallins orsequestered in the intracellular organelles (theendoplasmic reticulum, golgi apparatus, andmitochondria).


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Extracellular Ca2+ can be bound to lipidmolecules in the outer layer of the cellmembrane.

Reduced capacity of membrane lipids to bindCa2+ affects cell membrane permeability and

causes a deterioration of intracellular Ca2+homeostasis, a rise in intracellular Ca2+levels, the formation of calcium oxylatecrystals, the formation of strong bondsbetween Ca2+ and insoluble lens proteins,

increased light scattering, and nuclearcataract formation. Increased intracellular Ca2+ levels also affect

lens epithelial cell terminal differentiationcausing posterior subcapsular cataracts.


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Calpains

Calpains are a group of intracellular cysteineproteases, which are activated by Ca2+.

The physiological roles of calpains in the lens arepoorly understood, but they may be needed todegrade damaged lens proteins that accumulate

during the life of the lens. Calpains can contribute to cataract in two ways.

First, a lack of calpains can lead to pathologicallyelevated levels of damaged proteins, reducedoptical performance, and cause cataract.

Second, excessive stimulation of calpain activityby Ca2+ can also lead to unregulated proteolysisand cataract.

Calpain inhibitors could therefore be useful in thenonsurgical treatment of cataract.


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Oxidation

Oxidation is a key feature in thepathogenesis of most cataracts and lowoxygen levels (O2) are important formaintaining a clear lens.

There is a steep oxygen gradient from theouter part of the lens to the center.Mitochondria in the lens cortex removemost of the oxygen, thus keeping nuclearO2 levels low.

However, in older people mitochondrialfunction diminishes and superoxideproduction by the mitochondria increasesresulting in increased nuclear oxygen andsuperoxide levels.


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Defensive Mechanisms

Primary defenses are provided by antioxidantenzymes and antioxidants such as ascorbate,glutathione, tocopherols, and carotenoids, whichmaintain lens proteins in the reduced state.

Secondary defenses include proteolytic andrepair processes, which degrade and eliminatedamaged proteins, UV filters, and othermolecules such as glutathione reductase andfree radical scavenging systems.

Failure of these protective mechanisms, ashortage of antioxidants, and increased freeradicals result in cell membrane and proteindamage.


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Other Factors

Crystallins may have a numberof functions.

Decreased crystallin levelscause proteins to precipitate,which leads to cataractformation.


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CAUSES OF CATARACT


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Age

Many factors cause age-relatedcataract.

The cumulative effect of environmentalfactors (UV light, x-irradiation, toxins,metals, steroids, drugs, and diseases

including diabetes) plays a role.


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Trauma

Blunt trauma, which does not result in rupture ofthe capsule, may cause an anterior and/orposterior subcapsular cataract, or both.

Initially, fluid influx causes swelling andthickening of the lens fibers.

Later the fibers become less swollen; the anteriorsubcapsular region whitens and may develop acharacteristic flower-shaped pattern, or anamorphous or punctate opacity.

Penetrating injuries can be caused by accidentalor surgical trauma such as a peripheral iridectomyor during a vitrectomy.


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Systemic Disorders

In uncontrolled type 1 diabetes mellitus

In type 2 diabetic adults, an earlier onset age-related type of cataract occurs.

Galactosemia Fabrys disease

Lowes oroculocerebrorenal syndrome

Alports syndrome

Dystrophia myotonica

Rothmund-Thompson syndrome Werners syndrome

Cockaynes syndrome


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Dermatological Disorders

Both the skin and the lens share acommon embryological origin, the

ectoderm. Therefore, skin disordersmay be associated with cataractformation.

Atopic dermatitis and eczema Ichthyosis

Incontinentia pigmenti


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Central Nervous SystemDisorders

Neurofibromatosis type II

Zellweger syndrome

Norries disease


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Ocular Disease and Cataracts

Inflammatory uveitis (e.g., Fuchs heterochromiccyclitis and juvenile idiopathic arthritis) usuallyresults in posterior subcapsular or posterior corticallens opacities.

Infective uveitis (e.g., ocular herpes zoster andtoxoplasmosis, syphilis, and tuberculosis) cancause cataracts, but the organism does notpenetrate the lens.

Corticosteroid treatment can also cause cataracts. Retinal pigment degenerations such as retinitis

pigmentosa, Ushers syndrome, and gyrate atrophyare associated with cataracts, which are usually

posterior subcapsular opacities


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Retinal detachment and retinalsurgery may cause a posteriorsubcapsular cataract

Degenerative myopia is associated

with posterior cortical, subcapsular,and nuclear cataracts. Ciliary body tumors may be

associated with cortical or lamellar

cataract in the affected quadrant. Anterior segment ischemia may cause

a subcapsular or nuclear cataract,which progresses rapidly.


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Toxic Causes

Topical, inhaled, and systemicallyadministered steroids can cause posteriorsubcapsular cataracts. The mechanismsare poorly understood but direct andindirect mechanisms are involved.

Chronic use of long-actinganticholinesterases previously used inthe treatment of chronic open-angle

glaucoma may cause anteriorsubcapsular vacuoles and posteriorsubcapsular and nuclear cataracts.


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Visual Problems

Being sensitive to glare Cloudy, fuzzy, foggy, or filmy vision Difficulty seeing at night or in dim light Double vision

Loss of color intensity Problems seeing shapes against a background

or the difference between shades of colors Seeing halos around lights Cataracts generally lead to decreased vision,

even in daylight. Most people with cataracts havesimilar changes in both eyes, although one eyemay be worse than the other. Many people withthis condition have only mild vision changes.


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ASSESSMENT AND GRADINGOF CATARACTS

Direct ophthalmoscopy withretroillumination can be used to assess

and grade cataracts.The LensOpacification Classification System II(LOCS-II) slit-lamp grading system is

reproducible and has been validated.


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The Lens OpacificationClassification System II (LOCS-II)

Infantile cataracts anterior polar cataract

Spear cataract

Coralliform cataract

Floriform cataract Lamellar cataract

Cataracta centralis pulverulenta

Congenital punctate cerulean cataract

Congenital suture (stellate) cataract mittendorfsdot

Congenital disciform cataract


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Classification

Age-related diseases:a. Congenital

b. Juvenile

c. Senile

Complication

Diabetic

Secondary


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Congenital Cataract

A cataract present at birth or in aged lessthan 1 year.

It can affect one eye, which is known as

'unilateral cataract' or both eyes, which isknown as 'bilateral cataracts'.

Most children with cataract in only one eye

usually have good vision in the other.


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To know the exact cause of congenitalcataract it needs a prenatal history ofinfection (example: rubella) during the first

tri-semester of pregnancy and medicineused during pregnancy.

Cataract with positive urine reduction test

might be cause by galactosemia Almost 50% of congenital cataract is

sporadic and have an unknown cause

C


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Symptoms of CongenitalCataract Gray or white cloudiness of the pupil

(which is normally black)

Infant doesn't seem to be able to see

(if cataracts are in both eyes) "Red eye" glow of the pupil is missing

in photos, or is different between the

two eyes Unusual rapid eye movements

(nystagmus)


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Treatment

Surgical may be present if the fundusreflex is not shown

Surgical acts for congenital cataract

are lens incision, linear extraction,and extraction with aspiration


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Juvenile Cataract

A mature cataract with a poorlydeveloped nucleus in a child or youngadult, it developed by the age less

than 9 years and more than 3 months.(usually its a continuation of

congenital cataract)

A juvenile cataract cause bymanifestation of systemic or metabolicdisorder


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Senile Cataract Senile cataract

is one that forms as a result of theageing process and one most commonly found inthe elderly. The word senile comes from the Latinword for "old" and has nothing to do with mentalfaculties or behavior.


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Clinical Stages

There are four clinical stages in thesenile cataract:

a. Insipient cataract

b. Intumescent cataractc. Mature cataract

d. Hypermature cataract


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a. Insipient cataract

- Cloudiness starting from theedge of the equator, grilled-shaped head to anterior andposterior (cortical cataract)

- Vacuole starting to seen inside

the cortex- In the posterior sub capsular

cataract cloudiness starting toseen in the anterior part, wherethe cleave is form between thelens fiber and cortex whichcontain morgagni

- This cloudiness can lead topolioplia where the refractionindex is not the same in all of thepart of the lens


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b. Intumescent cataract- Cloudiness start and

acommpanying by swollen ofthe lens, where thedegenerative lens absorbedwater

- The swollen pushing the irisand make the eye chamberbecame shallow than normal

- Intumescent cataract usuallyhave a rapid progress which

can lead to lenticular miophy,where this condition cancause cortex hydration untilthe lens have a convex shapeand the refraction level willincrease than normal (known

as miopisation)


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Immature cataract

- Only part of the cloudiness found in thelens (not affected all the part),

- The volume of the degenerative lens willincrease due to the osmotic pressures

rise

- In a convex lens condition, the difficultiesin pupil will cause secondary glaucoma


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c. Mature cataract

- The cloudiness alreadycovered the masses of thelens, which caused bycalcium ions deposition

- If there is no surgicalprocedure during

intumescent or immaturecataract, then the liquid willcame out of the lens bringout the cloudiness all overthe lens, which in prolongedcondition will cause the

calcification of the lens- The anterior eye chamberwill be in the same normaldepth

- The iris reflection test will benegative, since the

cloudiness cover up the iris


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d. Hypermature cataract

- A continuation of

degenerative stage ofcataract , will result in hard,soft, or melting

- The degenerative lens masswill be out of the lens capsuleand the lens will be shrink,

yellow and dry.- Sometime the shrink process

will continue and make thezonular of zinn got loosen.

- If the cataract process

continue, accompanied bythick capsule, thedegenerative cortex willshown like a box of milk-shape with a drowning heavynucleus inside the cortex lens

(condition knows as Morgagnicataract)

Treatments been used for Senile


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Treatments been used for SenileCataract

Iodium liquid tear-drops, topical meds,iontophoresis,

Calcium cysteine,

Immunization in purpose to fix the lens

metabolic disorder

Lentokalin and cataractolysin made from fishlens and high dose of vitamin

Recent treatment is surgical procedure (withseveral condition; glaukoma, uveitis, or thevisual acuity is decreasing gradually and disturbthe daily activities)


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Complication Cataract

Cataract cause by other eyes diseases

manifestation like inflammation, or thedegenerative processes such as, retinal

detachment, retinitis pigmentosa,glaucoma, okular ischemic, and etc

Other than eye diseases, it can caused by

systemic endocrine disease

Di b i C


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Diabetic Cataract

The cataract in diabetic happen in 3 forms:

a. Patient with heavy dehydration, acidosis,hyperglycemia the lens will shown a line-cloudinessresult from a folding lens

b. Old and uncontrollable patient with diabetic juvenile,where the cataract happen in both eyes at the sametime in 48 hours (snow-flake shape or sub-capsularplate)

c. Mature diabetic patient, where the histological andbiochemical views are the same withy non-diabeticcataract patient


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Secondary Cataract

Result from the fibroses made from theremain of the lens (the result will came up

two days after EKEK (Extra CapsularCataract Extraction).


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Surgical Processes

Three types of surgical processes for cataract:a. Extra Capsular Cataract Extraction Surgical procedure to the cataract lens where the

action is to do the incision or tearing the lens inorder to pulling out the contain of the lens

b. Intra Capsular Cataract Extraction Surgical procedure where the lens is being pulled

out with the capsulec. Phacoemulsification (SICE)

offers the surgeon the possibility to break thenucleus into smaller pieces and even into a fineemulsion of material, all of which can be removedthrough the probe used to achieve the break-up.


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THANK YOU

Katarak-Fridayana FK Untan

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