Recent advances in corneal graft technology, including donor tissue retrieval, storage and surgical techniques, have greatly improved the clinical outcome of corneal grafts. Despite these advances, immune mediated corneal graft rejection remains the single most important cause of corneal graft failure. Several host factors have been identified as conferring a "high risk" status to the host. These include: more than two quadrant vascularisation, with associated lymphatics, which augment the afferent and efferent arc of the immune response; herpes simplex keratitis; uveitis; silicone oil keratopathy; previous failed (rejected) grafts; "hot eyes"; young recipient age; and multiple surgical procedures at the time of grafting. Large grafts, by virtue of being closer to the host limbus, with its complement of vessels and antigen-presenting Langerhans cells, also are more susceptible to rejection. The diagnosis of graft rejection is entirely clinical and in its early stages the clinical signs could be subtle. Graft rejection is largely mediated by the major histocompatibility antigens, minor antigens and perhaps blood group ABO antigens and some cornea-specific antigens. Just as rejection is mediated by active immune mediated events, the lack of rejection (tolerance) is also sustained by active immune regulatory mechanisms. The anterior chamber associated immune deviation (ACAID) and probably, conjunctiva associated lymphoid tissue (CALT) induced mucosal tolerance, besides others, play an important role. Although graft rejection can lead to graft failure, most rejections can be readily controlled if appropriate management is commenced at the proper time. Topical steroids are the mainstay of graft rejection management. In the high-risk situations however, systemic steroids, and other immunosuppressive drugs such as cyclosporin and tacrolimus (FK506) are of proven benefit, both for treatment and prevention of rejection.

Purpose: To document the clinical pattern in recurrent herpes simplex disease. Methods: Eyes with clinically documented pattern of corneal manifestation on more than one occasion were analysed. For each eye recruited, the clinical pattern of the disease at each recurrence of herpes simplex corneal disease, age, disease-free intervals, triggering factors, laterality and steroid abuse were noted and evaluated. Results: For an average follow up of 6.9 years, a recurrence rate of 0.6 episodes per year was observed. Disease-free intervals of 75.7 months for epithelial herpes simplex disease was considerably longer than the 21.3 months observed for stromal disease. Clinical pattern of recurrence was of the same type following first episode of disciform keratitis, epithelial keratitis and endothelitis in 84%, 72.7%, and 75% of the eyes respectively. Conclusion: Herpes simplex disease often recurs in the same manifest clinical pattern as the first episode. This clinical evidence provides additional support for the potential role of herpes simplex biotypes in determining manifestation of clinical disease pattern.

Purpose: To investigate the nature and frequency of use of Traditional Eye Medicine (TEM) for corneal ulcer in patients from predominantly rural background. Methods: We documented the the use of TEM by corneal ulcer patients presenting to a tertiary eye-care centre in South India during two months of 1996. Results: Of 283 patients enrolled in the study, 135 (47.7%) of the patients used TEM. There was no difference with regard to age and sex distribution of patients using TEM and those who did. Patients with history of trauma were more likely to use TEM. Common forms of TEM used were human breast milk 61(45.2%), leafy matter 40(29.6%), castor oil 16 (11.9%), and hen's blood 8 (5.9%). Conclusion: Though the awareness of intraocular lens implantation for cataract surgery is very high in this segment of the population, it is still tragic that an awareness of primary eye care following trauma has not been created. Health education is mandatory to prevent this avoidable cause of blindness.

Purpose: To report the role of Ultrasound Biomicroscopy (UBM) as a tool in the diagnosis and management of cyclodialysis clefts. Methods: Six eyes of 6 patients with hypotony and suspected or diagnosed cyclodialysis clefts underwent UBM evaluation. Post-treatment UBM was performed in four eyes to assess the effect of the treatment. Results: Cyclodialysis clefts were accurately diagnosed and delineated in 6 eyes by UBM. Complete closure was documented after treatment in 3 eyes, and a residual cleft in one eye. These findings were compared to gonioscopic findings. Conclusions: UBM is a safe, accurate and noninvasive diagnostic tool in the diagnosis of cyclodialysis clefts and is of particular use when other conventional methods of diagnosis are inconclusive.

Purpose: In vitro study of the enzymes involved in aerobic, anaerobic and hexose monophosphate shunt in ultraviolet radiation exposed mice lenses. Method: Of the selected enzymes, lactic dehydrogenase (LDH) was representative of anaerobic glucose oxidation, succinic dehydrogenase (SDH) of the aerobic oxidation, and Glucose-6-phosphate dehydrogenase (G-6-PDH) of the Hexose Monophosphate (HMP) shunt. Other enzymes studied were ATPase and glutathione reductase (GR). Results: Experiments with mice lenses in vitro showed that transparent lens became opaque following UV-irradiation at 360 nm. Opacification of the lens was accompanied by a change in enzyme activities for energy metabolism. Conclusion: These changes were progressive in a manner analogous to sequential morphological changes, which would be crucial in maintaining lens transparency.

Purpose: To evaluate the presence of transthyretin (TTR, prealbumin) a protein which binds retinol to retinol-binding protein in various ocular tissues and to study its quantitative changes in the vitreous humor in various diseases Method: Estimation of TTR was done by electrophoresis of 10 mg protein in each sample of tears, aqueous humor, vitreous, retina, and lens by an Imaging Densitometer using prealbumin as the standard. Results: TTR was present in all the eye structures except the lens and tear. The retina and the vitreous had relatively higher amounts of TTR compared with aqueous. The identity of TTR was confirmed by immuno-electrophoresis using anti-human TTR. Two bands in SDS electrophoresis revealed that this protein is a heterodimer. There was a significant decrease in vitreous TTR in diabetes with hypertension and increase in one case each of diabetes with hypertension associated with leukaemia or carcinoma with hepato-splenomegaly. Conclusion: Vitreous TTR is probably from retina and retinal pigment epithelium. The level of vitreous TTR is likely to have diagnostic significance in some retinal diseases.

Ophthalmologists are often confronted with difficult clinical management problems. In such cases, even published experience may be limited; consequently multiple, generally unproven management options are usually available. When placed in such situations, most of us decide on the most appropriate course of action based on intuition or (limited) previous experience. In this article, we use examples to introduce the concept of decision analysis, a method of generating objective decisions for complex clinical problems.

This paper describes a refresher training and continuing education programme in clinical and community ophthalmology for para-medical ophthalmic assistants (PMOAs) conducted by the Lions Aravind Institute of Community Ophthalmology. The course participants included 60 PMOAs working either in district hospitals, primary health centres or mobile units from the districts in Maharashtra. Each training programme was spread over 43 hours in 4 days and included lectures, practical demonstrations, and hands-on training in the outpatient, inpatient, and operation theatre of the training institution. Participants were given exposure to outreach activities in an eye camp and a satellite eye centre resembling a district hospital. The PMOAs found the training to be useful and it was seen that areas like patient counselling, instrument and equipment maintenance, and assistance in the operation theatre for newer surgical procedures which were lacking in the basic training were fulfilled in this training programme. Regional Institutes of Ophthalmology, upgraded medical colleges, and other eye-care institutions which have facilities and manpower could organise similar refresher and continuing education programmes for PMOAs so that they could be utilised more efficiently in the blindness-control activities in the country.