Gene therapy is a novel form of drug delivery that enlists the synthetic machinery of the patient's cells to produce a therapeutic agent. Genes may be delivered into cells in vitro or in vivo utilising viral or non-viral vectors. Recent technical advances have led to the demonstration of the molecular basis of various ocular diseases. Ocular disorders with the greatest potential for benefit of gene therapy include hereditary diseases such as retinitis pigmentosa, tumours such as retinoblastoma or melanoma, and acquired proliferative and neovascular retinal disorders. Gene transfer into ocular tissues has been demonstrated with growing functional success and may develop into a new therapeutic tool for clinical ophthalmology in future.

Purpose: To evaluate the clinico-pathologic features of intraocular osseous metaplasia. Methods: Pathology specimens of enucleated eyes submitted to the ophthalmic pathology service at a tertiary eye-care referral center between January 1995 and June 1999 were studied for intraocular osseous metaplasia. Specific histopathologic features noted in specimens with osseous metaplasia were the presence of retinal detachment, gliosis, retinal pigment epithelial hyperplasia, drusen, epiretinal membrane, fibrovascular proliferation and inflammation. Immunohistochemistry using monoclonal antibody against glial fibrillary acidic protein was performed to assess the glial component within the membranes and the proliferative vitreoretinal mass. Clinical records were reviewed and correlated with histopathologic findings. Results: Osseous metaplasiaS was noted in 8 of 151 (5.2%) eyes examined. Clinical diagnosis in these was phthisis bulbi, staphyloma, absolute glaucoma and microphthalmos. Enucleation was performed for relief of symptoms (in painful blind eyes) or for cosmesis, and in an eye inciting sympathetic ophthalmia. Retinal detachment, gliosis and retinal pigment epithelial hyperplasia were noted in all the cases. Drusen with calcification or ossification (5 of 8), fibrovascular proliferation in the vitreous (5 of 8) and active inflammation (4 of 8) were the other associated histologic features. Location of ossification was subretinal in 3 cases, preretinal (ora serrata) in 1 case and in both locations in 4 cases. The eyes with subretinal osseous metaplasia had associated calcified drusen, while preretinal ossification was seen within the fibrovascular membranes. Conclusion: Chronic retinal detachment, hyperplasia and transdifferentiation of retinal pigment epithelium appear to be a few of the prerequisites for intraocular osseous metaplasia. Ossification can occur at isolated subretinal and preretinal locations or can involve both. Though a larger study is required to postulate the chronology of events, in this small series, isolated subretinal ossification appears to be initiated by calcification and ossification of drusen, while in the pre-retinal region it is associated with vitreoretinal proliferation.

Purpose: To report a variant form of serpiginous choroiditis, that initially or predominantly involved the macular area. Methods: Nine eyes of 6 patients with the macular form of serpiginous choroiditis were evaluated clinically and angiographically in a longitudinal fashion for a period of 12-36 months. The active stage and the recurrences were treated by oral and periocular cortico steroids; and two patients were supplemented with oral azathioprine. Most of these patients were referred to our center with varied diagnoses. Results: In this group, 4 were male and 2 were female with an average age of 30.5 years. Three patients had bilateral macular lesions, two had typical serpiginous choroiditis in the fellow eye and the remaining one had unilateral macular involvement alone. The initial visual acuity was 6/60 or less in 60% eyes whereas the final visual acuity was 6/18 or better in 66% eyes. Angiographic findings were typical of serpiginous choroiditis characterised by early hypofluorescence followed by leakage and staining of the borders and the lesion itself without any evidence of choroidal ischaemia or retinal vascular abnormalities. Conclusion: The macular variant of serpiginous choroiditis can mimic many other macular pathologic lesions, thus posing a diagnostic dilemma. Because of its relentless destructive course, early diagnosis and prompt treatment is required to prevent sight-threatening complications.

Purpose: To study the safety and efficacy of intracameral lidocaine as anaesthesia in trabeculectomy for primary open-angle glaucoma. Methods: Trabeculectomy under intracameral anaesthesia using 1% preservative-free lidocaine was performed in 10 patients with primary open-angle glaucoma. Intraoperative pain score, postoperative intraocular pressure (IOP) and endothelial cell count at 3 months were recorded. Results: The mean pain score was 1.70 ± 1.34. The mean IOP was lowered from 24.60 ± 8.28 mmHg preoperatively to 14.1 ± 3.11 mm Hg postoperatively. There was no significant decrease in the mean endothelial cell count 3 months after the surgery (P = 0.375). Conclusion: Intracameral lidocaine may be a safe and effective alternative anaesthesia method in trabeculectomy for uncomplicated primary open-angle glaucoma.

PURPOSE: Age-related macular degeneration (ARMD) is clinically less common in India compared to the West. Therefore, clinicians are unfamiliar with histopathologic evidence of age-related macular changes in the Indian population. METHODS: Fifty consecutive human donor eyes removed for corneal grafting were studied for gross, microscopic and histochemical features of age-related changes in the macula in the Indian population. A horizontal block was cut from the globe including the optic disc, and the macula. Six sections, 6 microns thick, were cut from three levels in the macula at a distance of 140 microns. These were stained with haemotoxylin-eosin, periodic acid-Schiff, Mallory, Masson trichrome, alcian blue and von Kossa stains. The presence of basal laminar deposits, drusen and thickening and calcification of Bruch's membrane in the macula were assessed at 400 x magnification using a modified version of Sark's classification. RESULTS: Twenty-four donor eyes (48%) had some form of age-related macular change. These included basal laminar deposits, hard drusen, soft drusen, extensive retinal pigment epithelium atrophy of the macula, and disciform degeneration of macula. A combination of changes was often seen. Age-related changes were more common in the seventh and eighth decade. CONCLUSION: Our study shows that histological changes characteristic of the early stages of age-related macular degeneration are fairly common in the Indian population. However, advanced macular changes are significantly rare.

Purpose: The efficacy and safety of peribulbar anaesthesia was assessed using a combination of lidocaine, bupivacaine and clonidine during eye surgery. Methods: We prospectively studied 100 vitreo-retinal surgical procedures performed by several surgeons. The exclusion criteria included age below 30 years and, axial length of the orbit above 28 mm. Peribulbar was performed using Hamilton's technique. A mixed anaesthetic solution of equal quantity of lidocaine 2% and bupivacaine 0.5% with clonidine (1mg/kg) was injected. Patients received a mean volume of 14.5 ml ± 3.5 of the mixture. Akinesia and analgesia were assessed 15 minutes later by the surgeon. Whenever required, supplemental lidocaine 2% (3 ml) by sub- Tenon infiltration was added by the surgeon. Supplemental injections were given only to patients who failed to develop analgesia. Results: The mean age of patients (male 52%, female 48%) was 66 years ± 10 (mean ± SD, range 44-90). The 100 surgical procedures were made up of vitrectomy ± gas ± silicone oil (22/100), vitrectomy and lensectomy (6/100), vitrectomy and epiretinal membrane ± laser coagulation ± gas ± silicone oil (35/100), scleral buckling or encircling ± gas (36/100), and cryosurgery ± gas (1/100). Analgesia was adequate throughout surgery without any supplementation in 85% of cases and with a sub-Tenon infiltration in 99%. Akinesia was complete in 84%, mild in 12% and absent in 4% of cases. The sub-Tenon injection was performed in 15% of cases. Three patients (3%) were agitated during surgery. No neurologic or cardiac complication was seen. In one patient, the systolic blood pressure decreased from 170 to 110 mmHg, 30 minutes after the institution of the peribulbar block. Conclusion: Our results show that peribulbar anaesthesia in the proposed mixture offers excellent analgesia in 85% of patients, and in 99% of the patients when supplemented by a subtenon injection. The current mixture of lidocaine, bupivacaine and clonidine is an excellent alternative to the previously used mixture etidocaine, bupivacaine and hyaluronidase for vitreoretinal surgery. However, a randomized controlled clinical trial is needed to prove the efficacy and safety of these results.

Purpose: Medical professionals could enhance eye donation rates by reminding relatives during grief counseling at the time of patient's death. This study was designed to assess the knowledge and attitudes of final year medical students (future doctors) towards eye donation, prior to instruction in eye banking. Methods: The responses of 49 final-year medical students to a questionnaire on eye donation were compared with 24 non-medical students (controls). The results were analysed statistically using the chi-square test. Results: More than one-third of students and controls were unaware that eyes are removed within six hours of death. Eight (16.3%) students and 6 (25.0%) controls felt that a close relative's eyes could be donated after death only if he had indicated willingness (P=0.05). Three (6.1%) students and 3 (12.5%) controls were undecided about donating their own eyes. Nineteen (38.8%) students and 6 (25%) controls did not know where to go in order to pledge/donate eyes. The controls had poorer knowledge of ocular and systemic contraindications, and they did not know that storage could be prolonged (P<0.001). Only 27 (55.1%) students had knowledge of corneal storage. Conclusions: Controls were poorly informed about various aspects of eye donation suggesting inadequate dissemination of information by the media. Students and controls alike had misconceptions regarding donation of relatives' eyes and hesitation regarding their own. These aspects should be emphasized during undergraduate teaching to dispel misgivings regarding wastage of donor eyes and to encourage future doctors to promote eye donation.

Fungal keratitis is an important cause of corneal disease in the tropical world. We report a rare presentation of simultaneous bilateral corneal ulceration caused by different fungi.

We report a case of penicillium keratitis in vernal shield ulcer in the absence of corticosteroid use. This report illustrates super-added infection in vernal shield ulcer by an organism which is otherwise innocuous and forms a part of the normal ocular flora.

We report two cases clinically diagnosed as idiopathic uveal effusion syndrome, where indocyanine green angiogram suggest non-specific choroidal inflammation as the underlying cause. Treatment with non-steroidal anti-inflammatory drugs was beneficial.

We report the case of a 35-year-old aphakic patient who developed an intractable secondary glaucoma due to angle closure after pupillary block following the use of perfluoropropane (C3F8) gas at a nonexpansile concentration of 14%.

This report describes a rare case of hypertensive retinopathy with choroidopathy secondary to bilateral renal artery stenosis in a young non-pregnant female patient.

We describe a case of late ocular changes after lightning injury. One year after the injury, complete ankyloblepharon, severe dry eye, corneal opacity, healed iritis and mature cataracts were noted in both eyes of the patient.

We describe the preparation and preservation of human amniotic membrane required for transplantation in the management of ocular surface diseases. Informed consent is obtained and the donor is screened to exclude risk of transmissible infections such as human immunodeficiency virus (HIV), hepatitis B virus, hepatitis C virus, and Treponema pallidum infections. Ideally, the media and washing solutions needed for the preparation of amniotic membrane are prepared only a week to 10 days prior to use and not stored in the freezer weeks ahead. The AM obtained under sterile conditions after elective caesarian section is washed free of blood clots and chorion. With the epithelial surface up, amniotic membrane is spread uniformly without folds or tears on individually sterilized 0.22 μm nitrocellulose membranes of the required sizes. The prepared filter membrane with the adherent amniotic membrane is placed in the preservative medium and stored at -80°C. The membranes are released when the repeat serology for HIV after the window period has excluded virus infection in the donor. Depending on consumption they may be used up to 6 months after preparation, though many have recommended storage for an indefinite period. Since the amniotic membrane has only incomplete expression of HLA antigens and amniotic epithelial cells do not express them, it is not rejected after transplantation. The presence of several cytokines in the amniotic membrane promotes epithelialization with reduction of fibrosis during healing.

India has a large burden of blindness and population-based screening is a strategy commonly employed to detect disease and prevent morbidity. However, not all diseases are amenable to screening. This communication examines the issue of "population-based screening" versus "case detection" in the Indian scenario. Using the example of glaucoma, it demonstrates that given the poor infrastructure, for a "rare" disease, case detection is more effective than population-based screening.