PEMULIHAN SETELAH TRANSPLANTASI KORNEA Waktu yang dibutuhkan dalam proses pemulihan dapat mencapai satu tahun atau lebih. Pada beberapa minggu pertama, hindari olahraga yang berat atau mengangkat sesuatu yang berat. Dokter spesialis mata akan memberikan obat tetes mata steroid selama beberapa bulan untuk membantu pemulihan. Resipen kornea wajib menjaga matanya sepanjang waktu dengan memakai dop mata atau kacamata untu menghindari benturan, dan lain-lain. Pada umumnya jahitan akan dilepas saat tiga sampai 17 bulan setelah pembedahan, tergantung dengan keadaan mata resipien dan tingkat kesembuhannya.

Recovery following the transplant:The postoperative recovery is a long one, but in most cases, resumption of normal activities may occur soon after surgery with some reasonable limitations. For example, lifting heavy objects or strenuous exercise must be avoided until directed otherwise by the physician. Until the eye has healed, glasses or an eye shield must be worn to protect the eye.  The sutures used to sew the donor cornea in place are barely visible and do not cause pain. It is normal for the eye to feel scratchy or irritated for the first few days following surgery. As the cornea heals, some of the stitches used to sew the donor tissue into place are removed. This can be done quite easily in the doctor's office.

The final improvement in vision is gradual and occurs six to twelve months post-operatively. Once the cornea stabilizes, improved vision is usually enjoyed. The results and success in restoring vision usually depend more on the state of the original disease than the actual surgical manipulation.  In quantitative terms success rates vary from 90-95 percent.

Cornea Transplant Procedure

Once you and your doctor have decided that a corneal transplant is the best option to restore your functional vision, your name is placed on a list at a local eye bank. The waiting period for a donor eye is generally one to two weeks due to a very sophisticated eye bank system in the United States.

A corneal transplant might be required in cases of eye conditions such as an eyelid that turns inward (trichiasis), causing eyelashes to rub against and scar the eye's surface.

Before donor corneas are released for transplant, the tissue is checked for clarity. Also, donor eyes supplying transplant tissue are meticulously screened for presence of diseases such as hepatitis and AIDS or other damage to ensure the health and safety of the recipient.

Typically, corneal transplants are performed on an outpatient basis, meaning that you will not need hospitalization. Local or general anesthesia is used, depending on your health, age and whether or not you prefer to be asleep during the procedure. With local anesthesia, an injection into the skin around your eye is used to relax muscles that control blinking and eye movement, and eye drops are used to numb the eye itself.

After the anesthesia has taken effect, the eyelids are held open with a special instrument (lid speculum). Your eye surgeon inspects and measures the affected corneal area in order to determine the size of donor tissue needed.

A round, button-shaped section of tissue is then removed from your diseased or injured cornea. Any additional work, such as cataract removal, is completed. A nearly identical-shaped button from the donor tissue is then sutured into place. Finally, the surgeon will place a plastic shield over your eye to protect it from being inadvertently rubbed or bumped. The surgery takes one to two hours.

Recovering From a Cornea Transplant

The total recovery time for a corneal transplant can be up to a year or longer. Initially, your vision will be blurry and the site of your corneal transplant may be swollen and slightly thicker than the rest of your cornea. As your vision improves, you will gradually be able to return to your normal daily activities.

For the first several weeks, heavy exercise and lifting are prohibited. However, you should be able to return to work three to seven days after surgery, depending on your job. Steroid eye drops will be prescribed for several months to help your body accept the new corneal graft. You should keep your eye protected at all times by wearing a shield or a pair of eyeglasses so that nothing inadvertently bumps or enters your eye.

Stitches usually are removed three to 17 months post-surgery, depending on the health of your eye and the rate of healing. Adjustments can be made to the sutures surrounding the new cornea to help reduce the amount of astigmatism resulting from an irregular eye surface.

Sumber : Jessica Hill, dari: http://www.allaboutvision.com/conditions/cornea-transplant.htm#ixzz1FIPshWuI

Postoperative care: the key to successful corneal graftsMeasures for reducing the rate of corneal graft rejection

01 April 2007 By: Lynda Charters Ophthalmology Times Europe Volume 3, Issue 3

Just as the preoperative evaluation of patients about to undergo a corneal transplantation involves numerous factors, so does the postoperative management of patients who have undergone these procedures, especially penetrating keratoplasty (PK). Here David D. Verdier, MD, outlines the best way to care for these patients, placing special emphasis on corneal surface problems, which he believes are responsible for an alarmingly high percentage of graft failures.

Which antibiotic?

Fourth-generation fluoroquinolones are the antibiotics of choice following corneal transplantations. The usual regimen is four times daily for seven days. "Hopefully, by the end of the administration of the antibiotics, epithelialization has occurred. If it has not it is pursued aggressively. I continue the antibiotics twice a day until epithelialization does occur," Dr Verdier said.

Steroid administration in his hands consists of 1% prednisolone acetate four times a day for at least one month. The dose is then tapered over the next few months to about once a day. The patients

then take the steroid once a day for about one year and they then are switched to a milder steroid such as fluorometholone. "If the patient is not phakic, this drug will be continued indefinitely because of the ongoing risk of rejection of the graft," Dr Verdier explained.

Rejection often not the main reason for graft failure

It is often thought that transplants are most likely to fail because of rejection, but Dr Verdier, who has been performing the procedure for 15 years, says that this is simply not the case: "Probably half of our transplants fail because of surface problems." So what is the best way to pre-empt and deal with this? Dr Verdier recommends using a non-preserved ointment four times a day for the first month following surgery. Despite patients often not liking this method, he maintains that it is the best option and frequently uses it for up to a year depending on whether the subject has punctate keratitis.

After care also requires frequent examinations — a minimum of six or seven times during the first year and even more frequently during the early postoperative period. "It is important to keep seeing these patients at least every six to eight months until all the sutures have been removed as they can come in asymptomatic but with suture-related problems," he said. During re-examinations after the first year, he also recommends looking for signs of late endothelial failure or rejection of the graft.

Re-emphasizing the importance of meticulous management of the corneal surface after transplantations, he commented, "The corneal surface is the most important factor to pay attention to, especially in the first several weeks postoperatively. The corneal surface is under a great deal of stress in that it is neotrophic because the nerves have been cut, and there is uneven spreading of tear film, because of abnormal tissue contour." Cyclosporine ophthalmic emulsion 0.05% (Restasis, Allergan) may be helpful in some of these cases.

If patients do not show signs of re-epithelization within one week of surgery, Dr Verdier suggests inserting punctal plugs; he prefers to use ones that are visible and that do not dissolve. If re-epithelization still has not occurred within 10 to 14 days, he then performs a suture tarsorrhaphy. "I believe that this approach works better than pressure patching, which we also sometimes use. Suture tarsorrhaphy can be performed in an office setting. This procedure is much under-utilized; by the time it is performed it is about a week later than it should have been done," he said.

Taking care of the sutures

Most of the sutures holding the corneal graft in place should be left in place to provide support for at least nine to 12 months. The older the patient is, the longer the sutures need to be left in place. In contrast, in infants the sutures may have to be removed in two to four weeks. "If during examination, a loose, broken, or a marginally eroding suture is observed, it should be removed. If a running suture is broken, the ends should not be clipped, the entire suture should be removed. A broken suture invites infection and neovascularization, and it needs to be removed," he emphasized. It is also important that sutures can be visualized easily in order to avoid missing any. Regular examinations with fluorescein stains or fluorescein and cobalt blue light will help prevent this problem from arising.

Besides having negative effects, Dr Verdier points out that sutures "can be our friends." This is especially true in cases where a combined technique is used, in which both running and interrupted sutures are inserted, or if there are a number of interrupted sutures. The sutures can be removed at the steep axis and help eliminate astigmatism. "Once the sutures are removed, there is usually a reduction in irregular astigmatism. This will result in a substantial improvement in vision even though there may be a higher degree of regular astigmatism." Evolving corneal posterior lamellar transplantation techniques such as Descemet's stripping endothelial keratoplasty (DSEK) may also help to eliminate many suture-related problems.

Sumber : http://www.oteurope.com/ophthalmologytimeseurope/Cornea/Postoperative-care-the-key-to-successful-corneal-g/ArticleStandard/Article/detail/415198

Prosedur Enukleasi. Mata yang akan diambil diperlakukan seperti tindakan melakukan pembedahan di kamar bedah. Pembedah akan me-makai sarung tangan steril dengan memakai masker. Daerah pembedahan dibersihkan dengan betadin dan kain penutup ber-lubang. Kelopak mata dibuka dengan spekulum kelopak kawat. Seluruh tepi limbus dilepas dari konjungtiva yang menempel padanya. Dicari seluruh otot penggerak mata dengan pengkait otot dan digunting. Spekulum kelopak di lepas dan bola mata diprolapskan keluar. Saraf optik digaet dengan sendok saraf optik dan kemudian dimasukkan gunting di bawahnya yang akan

menggunting saraf tersebut. Bola mata yang keluar kemudian dicuci dengan garam fisiologik dan larutan antibiotika. Mata dimasukkan ke dalam botol. Botol ini dimasukkan ke dalam kotak pengantar yang dapat ditutup sehingga suhu dapat bertahan 4 derajat Celsius. Di dalam pengawetan dengan ruang lembab ini mata dikirim ke Bank Mata

Postoperative management of corneal graft

Jagjit S SainiPostgraduate Institute of Medical Education and Research, Chandigarh, India

How to cite this URL:Saini JS. Postoperative management of corneal graft. Indian J Ophthalmol [serial online] 1994 [cited 2011 Feb 28];42:215-7. Available from:http://www.ijo.in/text.asp?1994/42/4/215/25558

Corneal transplantation has become a very successful procedure due to advances in eye banking, corneal surgery and postoperative treatment. Corneal grafts are prone to complications which may appear trivial but may lead to corneal graft failure. Familiarity with routine postoperative care and early detection of minor complications prevents this problem. Transparent corneal grafts often need additional procedures to optimise visual and functional recovery. The success of keratoplasty, more than any other ophthalmic surgery, depends on careful and diligent postoperative care. Both the patient and the surgeon must be constantly alert to changes in the eye so that problems can be promptly treated. This section will review the current guidelines for the postoperative care of a patient with corneal graft.

Immediate Postoperative Care

At the completion of suturing of the host-graft junction, an antibiotic and steroid combination may be given subconjunctivally. A short-acting mydriatic (cyclopentolate 1%) is instilled topically and the eye is patched with a gauze pad and a rigid metallic or plastic eye shield. Patients are generally encouraged to have a normal diet and change over to comfortable body posture soon after the surgery. As soon as patients recover from the effects of anaesthesia they are permitted regular activities. It is important, however, to instruct the patient to avoid direct trauma to the eye. In any activity where the patient is not comfortable because of poor vision in the fellow eye or systemic disability, assistance should be taken to prevent any injury to the operated eye.

Many patients may request for a mild analgesic on the first day. Stronger medications are almost never needed, and the need for them should alert the surgeon to the presence of possible complications.

In the eyes suspected to have postoperative rise of intraocular pressure (IOP) including when viscoelastic substances such as sodium hyaluronate have been left in the anterior chamber during surgery, systemic oral acetazolamide 250 mg is administered. There is no routine need for systemic antibiotics after the corneal transplant.

2. Follow-up Care

2.1 Follow-up: Evaluation and Frequency

It is mandatory to evaluate the eye on slit-lamp for wound integrity, epithelial defects, corneal oedema, IOP, iritis, and the possibility of infection on the first postoperative day. If any of these complications manifest or persist, evaluation of the operated eye should be continued on a daily basis for a few more days. As soon as the condition becomes normal, further evaluation may be at the end of a week followed by every two weeks for one month and then every month for the first year. In the absence of any complications, scheduled evaluations at increasing intervals of once or twice a year are adequate.

It is important to emphasize to the patient the danger signals and to report immediately should these problems occur. Each patient should be cognizant of symptoms such as sudden onset of redness of the eye, increasing sensitivity to light (photophobia), loss of vision or clouding of donor cornea, and persistent and increasing eye pain. It may be a good practice to have written instructions delivered to the patient. Since most complications can be successfully treated with early intervention, appropriate instructions to the patient are useful.

2.2 Early Wound Problems

The eye patch is removed on the first postoperative day. During the day time the patient is instructed to wear glasses which may have appropriate optical correction for the fellow eye. It is not always necessary to wear dark glasses. A rigid eye shield must be worn by the patient at night time for 8 weeks.

Wound leaks are rare with current microsurgical techniques but should be looked for carefully. Unusual localised oedema at the host-graft junction, a shallow anterior chamber with or without peaking of the pupil, and low IOP should arouse a suspicion of wound leak which may be confirmed on Siedel's test. Patching and/or a bandage contact lens should be an adequate treatment for minor leaks. However, when the anterior chamber remains collapsed for 48 hours or the leak persists for 4 days, additional sutures should be . placed to close the leak. Iris prolapse should be repaired immediately.

Complete epithelialisation of graft surface usually occurs within 2 to 3 days. If an epithelial defect is persistent, patching of the eye during day time or direct taping of lids is done. For more recalcitrant cases bandage contact lenses or lateral tarsorrhaphy may be required. Epithelial defects need close monitoring because of their potential to cause rejection, infection, thinning and perforation of the graft.

2.3 Medications

Topical steroid drops are instilled in the operated eye four times a day initially and the frequency is increased or decreased depending on the degree of inflammation. At the end of one month following surgery, most of the patients will need steroid drops two times a day. This dosage of medication is continued for three months. In eyes where inflammatory signs persist, topical steroids may be continued longer. Reversal of graft rejection will need more intensive topical steroids. This may be continued at one drop a day or on alternate days until all sutures are removed.

Topical antibiotics are discontinued at the end of one week and there is no suspicion of infection. Short-acting cycloplegic (cyclopentolate 1%) may be instilled till iritis subsides and may be discontinued after the first week.

In the event of acute redness of the eye, the patient should be advised to initiate topical instillation of antibiotic-steroid combination one hourly.

2.4 Suture Removal

The decision to remove sutures in a corneal transplant is complex yet critical to the final visual outcome and is primarily based on sound clinical judgement. Loose sutures need to be removed as they contribute to immunologic stimulus leading to graft rejection and infection. Although corneal vascularization is usually a sign of wound healing and an indication for suture removal, it may not be a foolproof sign. The timing of suture removal may vary depending on the preoperative pathology and age of the patient. In children, suture removal may be required sometimes as early as one week and in adults with avascular host disease, one may delay suture removal for 12 to 18 months in the absence of other indications. Our preferred method is to cut interrupted sutures at the curve of the suture with a disposable 26-gauge hypodermic needle under slitlamp magnification. The suture is cut on the host cornea and gently teased to facilitate grasping with forceps. With running 10-0 nylon sutures every other loop in the host cornea is first cut, leaving an intact loop that is also grasped in the host tissue and pulled peripherally. It is important that topical antibiotics are instilled for 3 days and the eye is examined 24 to 48 hours after suture removal for epithelial defect, wound override or dehiscence. The dosage of topical steroids should be increased immediately after suture removal and tapered over a 2 to 4 week period.

2.5 Intraocular Pressure

Almost one-third of the eyes develop rise of IOP following penetrating keratoplasty. The incidence in aphakic eyes is higher (42 to 89%). IOP is accurately assessed by Tono-Pen or pneumatic applanation tonometer. Inadequate control of IOP after penetrating keratoplasty is one of the leading causes of graft failure. It is mandatory that IOP be assessed accurately, early and at every visit. Several factors including inflammation, mechanical problems and steroidinduced side-effects can contribute to the rise of IOP. Elucidation of pathogenesis of glaucoma will help application of appropriate therapy. Trabeculectomy with or without antimitotic metabolites may be indicated in eyes when the conjunctiva is mobile. With fewer complications, ease of initial and repeat treatment with Nd: YAG laser is being used more frequently. In places where these facilities do not exist, conventional cyclocryotherapy is very effective particularly in aphakic eyes.

2.6 Infections

The reported incidence of postkeratoplasty infections ranges from 1.8 to 11.9%. In order to prevent infection, loose or ruptured sutures should be aggressively managed postoperatively. Following suture removal, the eye should be monitored for 48 hours for possible infection. All corneal grafts with persistent epithelial defects should be monitored for healing and infection. The overall prognosis for postoperative infectious keratitis is poor. Careful attention to high-risk factors such as loose, broken sutures and epithelial defects will help prevent postkeratoplasty infections. All postoperative patients should be asked to seek immediate treatment if a white spot is seen on the eye or sticky discharge persists for 24

hours.

2.7 Visual Rehabilitation

Astigmatism remains a major obstacle for visual rehabilitation after penetrating keratoplasty. Selective suture removal has been shown to hasten visual rehabilitation. Keratometry photokeratoscopy, slit-lamp examination and manifest refraction help identification of any tight sutures. Selective suture removal begins at about 6 weeks and only one or two sutures are removed at one time. The cornea is evaluated every 2 weeks for change in contour and further sutures are removed. If astigmatism is still present at the end of 8 to 9 months, incisional arcuate keratotomy in the wound or inside the wound is planned in the steeper meridian which corrects 4-6 D of astigmatism. The incision length and depth should vary , depending upon the type of wound healing that has yielded the astigmatism. Intraoperative keratometry helps to optimise the grading of length and depth of the incision according to the effect achieved during the surgical procedure. Progressive deepening and lengthening of the incision is performed first on one side and then on the other side until keratometer mire is assessed to be spherical. It is not necessary to overcorrect. Additional compression sutures in the flatter meridian may be employed to enhance the effect. In situations where significant astigmatism continues to be an obstacle to visual rehabilitation, more drastic methods of wedge resection, wound revision and repeat keratoplasty may have to be considered. When indicated, radial incisions on the graft may be performed in combination with intraincisional relaxing incisions or arcuate incisions.

As soon as the refraction is observed to have stabilised appropriate glasses or contact lenses are prescribed and this may take 2 to 6 months. Contact lens fitting in a postkeratoplasty eye is not always successful. A rigid gas permeable (RGP) contact lens centred over the graft is ideal but seldom achieved. If the visual acuity is good despite lens decentration, a contact lens is prescribed.

3. Resumption of Activities

In general, near normal activity can be resumed soon after surgery. However, it is necessary to explain to the patient the risk of direct injury to the eye and maintenance of ocular hygiene to prevent infection particularly in the first few weeks after surgery. In the first two weeks, unusual degrees of physical strain should be avoided. Contact sports should be avoided as well as any sports with risk of blunt injury. One could return to normal work after a week unless the work involves significant amount of manual or physical strain.

4. Conclusion

For long term success following penetrating keratoplasty, it is desirable that both the surgeon and the patient must be constantly alert to the changes in the eye so that problems can be promptly treated. The care of the corneal transplant is a lifelong commitment. Most complications can be successfully reversed and the grafts saved when the problems are detected early and treated. Educating the patient and the referring physician to contact the surgeon immediately about any change in the condition of the eye may be the most important factor in the success or failure of corneal transplant. In our experience, written instructions ensure better compliance

KERATOPATI BULOSADEFINISIKeratopati Bulosa adalah pembengkakan kornea yang paling sering terjadi pada usia lanjut.

Ada 2 macam keratopati bulosa: Keratopati Bulosa Afakik : jika lensa alami telah diangkat dan tidak diganti dengan lensa

buatan Keratopati Bulos Pseudofakik: jika lensa alami telah diganti oleh lensa buatan.

PENYEBABKesehatan kornea berhubungan erat dengan jumlah sel endotelial. Sel endotelial adalah sel-sel yang terletak di kornea bagian belakang dan berfungsi memompa cairan dari kornea sehingga kornea relatif tetap kering dan bersih.

Sejalan dengan bertambahnya usia, terjadi pengikisan sel-sel endotel yang terjadi secara bertahap. Kecepatan hilangnya sel endotel ini berbeda pada setiap orang.

Setiap pembedahan mata (termasuk operasi katarak dengan atau tanpa pencangkokan lensa buatan), bisa menyebabkan berkurangnya jumlah sel endotel. Jika cukup banyak sel endotel yang hilang, maka kornea bisa membengkak.

Peradangan intraokuler (uveitis) dan trauma pada mata juga bisa menyebabkan hilangnya sel endotel sehingga meningkatkan resiko terjadinya keratopati bulosa.

GEJALAPenglihatan penderita menjadi kabur, yang paling buruk dirasakan pada pagi hari tetapi akan membaik pada siang hari.

Ketika tidur kedua mata terpejam sehingga cairan tertimbun di bawah kelopak mata dan kornea menjadi lebih basah. Jika mata dibuka, cairan berlebihan ini akan menguap bersamaan dengan air mata.

Pada stadium lanjut akan terbentuk lepuhan berisi cairan (bula) pada permukaan kornea. Jika bula ini pecah, akan timbul nyeri yang hebat dan hal ini meningkatkan resiko terjadinya infeksi kornea (ulserasi).

DIAGNOSADiagnosis ditegakkan berdasarkan gejala dan hasil pemeriksaan mata.

Dengan slit lampbisa diketahui adanya lepuhan, pembengkakan dan pembuluh darah di dalam stroma.

Untuk menghitung jumlah sel endotel bisa dilakukan pemeriksaan mikroskopi spekuler.

PENGOBATANTujuan pengobatan adalah mengurangi pembengkakan kornea. Karena itu diteteskan larutan garam (natrium klorida 5%) untuk membantu menarik cairan dari kornea.

Jika tekanan di dalam mata meningkat, diberikan obat glaukoma untuk mengurangi tekanan yang juga berfungsi meminimalkan pembengkakan kornea.

Jika bula pecah, diberikan obat anti peradangan, larutan natrium klorida 5%, salep/tetes mata antibiotik, zat pelebar pupil dan lensa kontak yang diperban; guna membantu penyembuhan permukaan mata dan mengurangi nyeri.

Jika penyakitnya berat dan tidak dapat diatasi dengan tindakan di atas, mungkin perlu dipertimbangkan untuk menjalani pencangkokan kornea.

Xerophthalmia adalah kelainan pada mata, ditandai dengan kekeringan pada selaput lendir (conjungtiva) atau bagian putih dari mata, dan kekeringan pada selaput bening (cornea) atau bagian hitam mata yang berfungsi sebagai jalan masuknya cahaya ke dalam bola mata.

Xerophtalmia merupakan suatu tahap lanjutan akibat kekurangan vitamin A setelah seorang anak mengalami tahap seperti diare, kista, anemia, gangguan pertumbuhan. ”Ini diawali dengan kondisi kekurangan gizi yang dibiarkan saja. Xerophtalmia sendiri bisa berakibat kebutaan kalau tak mendapat pengobatan

Namun, sebelum gejala-gejala spesifik dari xerophthalmia muncul, pada anak sudah tampak gejala-gejala umum kekurangan vitamin A. Mula-mula anak sulit beradaptasi dalam suasana gelap, terutama jika meninggalkan suasana terang masuk ke suasana gelap. Keadaan ini dikenal sebagai nyctalopia -- buta senja atau buta ayam.

Keadaan selanjutnya, mulai terjadi kekeringan pada mata karena pengeluaran air mata berkurang, bagian putih mata menjadi mengeriput dan warna jadi kecoklatan. Keadaan ini dikenal sebagai xerosis conjungtivae. Keadaan ini dapat disertai dengan munculnya bercak putih seperti busa sabun, biasanya berbentuk segitiga pada tepi luar mata dekat dengan cornea.

Kemudian, keadaan berlanjut menjadi xerosis corneae -- cornea menjadi kering, mengeriput dan keruh. Cornea lalu akan melunak (keratomalacia) dan akhirnya terjadi luka pada bagian cornea (ulcus corneae). Pada proses penyembuhannya akan meninggalkan bekas yang disebut sikatrik atau jaringan parut yang permanen. Sampai tingkat xerosis corneae, kelainan yang muncul masih dapat kembali normal. Namun, jika sudah menyebabkan keratomalacia, maka akan terjadi kebutaan yang tidak dapat disembuhkan.

Kornea (latin cornum=seperti tanduk) adalah selaput bening mata, bagian selaput mata yang tembus cahaya, merupakan lapisan jaringan yang menutup bola mata sebelah depan. Kornea ini disisipkan ke sklera di limbus, lekuk melingkar pada persambungan ini disebut sulkus skleralis.5

Kornea memiliki diameter horizontal 11 – 12 mm dan berkurang menjadi 9 – 11 mm secara vertikal oleh adanya limbus. Kornea dewasa rata-rata mempunyai tebal 0,54 mm di tengah, sekitar 0,65 mm di tepi. Kornea memiliki tiga fungsi utama :1,6

Sebagai media refraksi cahaya terutama antara udara dengan lapisan airmata prekornea. Transmisi cahaya dengan minimal distorsi ,penghamburan dan absorbsi. Sebagai struktur penyokong dan proteksi bola mata tanpa mengganggu penampilan optikal.

Dari anterior ke posterior, kornea mempunyai lima lapisan yang terdiri atas:1

1. Epitel o Tebalnya 50 um, terdiri atas lim lapis sel epitel tidak bertanduk yang saling tumpang

tindih; satu lapis sel basal, sel poligonal, dan sel gepengo Pada sel basal sering terlihat mitosis sel, dan sel muda ini terdorong ke depan menjadi

lapis sel sayap dan semakin maju ke depan menjadi sel gepeng. Sel basal berkaitan erat dengan sel basal di sampingnya dan sel polygonal di depannya melalui desmosom dan macula okluden; ikatan ini menghambat pengaliran air, elektrolit, dan glukosa yang merupakan barrier.

o Sel basal menghasilkan membran basal yang melekat erat kepadanya. Bila terjadi gangguan akan mengakibatkan erosi rekuren.

o Epitel berasal dari ektoderm permukaan2. Membrana Bowman

o Terletak di bawah membran basal epitel kornea yang merupakan kolagen yang tersusun tidak teratur seperti stroma dan berasal dari bagian depan stroma

o Lapisan ini tidak mempunyai daya regenerasi3. Stroma

o Terdiri atas lamel yang merupakan susunan kolagen yang sejajar satu dengan lainnya, pada permukaan terlihat anyaman yang teratur sedang di bagian perifer serat kolagen ini bercabang; terbentuknya kembali serat kolagen memakan waktu lama yang kadang-kadang sampai 15 bulan. keratosit merupakan sel stroma kornea yang merupakan fibroblast terletak di antara serat kolagen stroma. Diduga keratosit

membentuk bahan dasar dan serat kolagen dalam perkembangan embrio atau sesudah trauma.

4. Membrana Descemeto Membran aselular;merupakan batas belakang stroma kornea dihasilkan sel endotel

dan merupakan membran basalnya.o Bersifat sangat elastis dan berkembang terus seumur hidup, tebal 40 um.

5. Endotelo Berasal dari mesotelium, berlapis satu, bentuk heksagonal, tebal 20-40 um. Endotel

melekat pada membran descement melalui hemidesmosom dan zonula okluden.1

Kornea dipersarafi oleh banyak saraf sensorik terutama berasal dari saraf siliar longus, saraf nasosiliar, saraf V saraf siliar longus berjalan suprakoroid, masuk ke dalam stroma kornea, menembus membrana Bowman melepaskan selubung Schwannya. Seluruh lapis epitel dipersarafi sampai pada kedua lapis terdepan tanpa ada akhir saraf. Bulbus Krause untuk sensasi dingin ditemukan di daerah limbus. Daya regenerasi saraf sesudah dipotong di daerah limbus terjadi dalam waktu 3 bulan. Kornea bersifat avaskuler, mendapat nutrisi secara difus dari humor aquos dan dari tepi kapiler. Bagian sentral dari kornea menerima oksigen secara tidak langsung dari udara, melalui oksigen yang larut dalam lapisan air mata, sedangkan bagian perifer, menerima oksigen secara difus dari pembuluh darah siliaris anterior.

Trauma atau penyakit yang merusak endotel akan mengakibatkan sistem pompa endotel terganggu sehingga dekompensasi endotel dan terjadi edema kornea. Endotel tidak mempunyai daya regenerasi.

Kornea merupakan bagian mata yang tembus cahaya dan menutup bola mata di sebelah depan. Pembiasan sinar terkuat dilakukan oleh kornea, di mana 40 dioptri dari 50 dioptri pembiasan sinar masuk kornea dilakukan oleh kornea. Transparansi kornea disebabkan oleh strukturnya yang seragam, avaskularitasnya, dan deturgensinya.1

Keratitis Neuroparalitik                                Merupakan keratitis akibat kelainan nervus trigeminus, sehingga terdapat kekeruhan kornea yang tidak sensitif disertai kekeringan kornea. Penyakit ini dapat terjadi akibat herpes zoster, tumor fossa posterior, dan keadaan lain sehingga kornea menjadi anestetis. 1,4

Penderita mengeluh ketajaman penglihatannya menurun, lakrimasi, silau tetapi tak ada rasa sakit. Uji fluoresin (+). 3. Xeroftalmia Merupakan kelainan mata yang disebabkan oleh difisiensi vitamin A dan sering disertai Malnutrisi Energi Protein, yang banyak dijumpai pada anak, terutama anak di bawah 5 tahun. Keadaan ini merupakan penyebab kebutaan utama di Indonesia. 1

Departemen kesehatan Republik Indenesia, mengklasifikasikan Xeroftalmia, menjadi; 1

a) Stadium I = Hemeralopia b) Stadium II = Stadium I + Xerosis konjungtiva dan kornea c) Stadium III = Stadium I dan II + Keratomalasia yaitu mencairnya kornea.