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ABSTRACT.Purpose: To study the effect of environmental toxins on the ocular surface in persons travelling through highly polluted areas of the metropolis of Delhi. Methods: A total of 500 apparently healthy volunteers recruited from the metropolis of Delhi were examined to establish the frequency of ocular surface disorders. All subjects underwent a slit-lamp examination, tear break-up time (BUT) test, Rose Bengal test, Schirmer's test and tear lysozyme level test. Results: Subjects in the study group had significantly higher levels of ophthalmic symptoms compared to the control group. In all, 105 (42%) and 125 (50%) subjects in the study group compared to 50 (20%) and 65 (26%) in the control group complained of redness and irritation (p < 0.05). There was no significant difference in visual acuity (VA) between the two groups, with best corrected VA being 6/9 or better in 92% of the study group and 96% of the control group. The average (±standard deviation) Schirmer's test result was 13.42±6.67 mm in the study group compared to 15.95±6.14 mm in the control group. This difference was statistically significant. The BUT was also significantly lower in the study group (12.97±6.12 seconds) compared to the control group (19.23±5.70 seconds) (p < 0.001). The Rose Bengal test and tear lysozyme activity did not show any significant difference between the two groups. Conclusion: According to our study, environmental conditions appear to have a very significant effect on the ocular surface. There were very high levels of subclinical ocular surface changes among persons travelling in highly polluted areas.

Cataract is the leading cause of blindness worldwide. It is a multifactorial disease primarily associated with oxidative stress produced by free radicals. The protection offered by various antioxidants in cataract development is well established. Polyphenolic compounds present in green tea (Camellia sinensis) are reported to possess antioxidant property in various pathological conditions. The present study was undertaken to evaluate the anticataract potential of green tea leaf (GTL) extract in the development of lens opacification. Enucleated rat lenses were randomly divided into normal, control and treated groups and incubated for 24 h at 37°C. Oxidative stress was induced by sodium selenite in the culture medium of the two groups (except the normal group). The medium of the treated group was additionally supplemented with GTL extract. After incubation, lenses were subjected to glutathione and malondialdehyde estimation. Enzyme activity of superoxide dismutase, catalase and glutathione peroxidase was also measured in different sets of the experiment. In vivo cataract was induced in 9-day-old rat pups of both control and treated groups by a single subcutaneous injection of sodium selenite. The treated pups were injected GTL extract intraperitoneally prior to selenite challenge and continued for 2 consecutive days thereafter. Cataract incidence was evaluated on 16th postnatal day by slit lamp examination. There was positive modulation of biochemical parameters in the organ culture study. Green tea was also found to reduce the incidence of selenite cataract in vivo. The results suggest that green tea possesses significant anticataract potential and acts primarily by preserving the antioxidant defense system.

Aqueous extract of OS possesses potential anticataract activity against selenite-induced experimental cataractogenesis. The protective effect was supported by restoration of the antioxidant defense system and inhibition of protein insolubilization of rat lenses as well.

Cataract is a multifactorial disease. Osmotic stress, together with weakened antioxidant defence mechanisms, is attributed to the changes observed in human diabetic cataract. Epidemiological studies provide evidence that nutritional antioxidants slow down the progression of cataract. The usefulness of lycopene, a dietary carotenoid, in the pathogenesis of human cataracts has not been studied so far. Since the epithelium is the metabolic unit of the lens, the effect of lycopene on galactose-induced morphological changes and antioxidant status of human lens epithelial cells (HLEC) in culture was evaluated in the present study. HLEC of fresh cadaver eyes obtained from an eye bank were cultured in medium supplemented with fetal calf serum (200 ml/l). On confluency, the cells were subcultured in medium containing either 30 m-d-galactose or 30 mM-d-galactose + lycopene (5, 10 or 20 μM) for 72 h. The cells were observed under the phase-contrast microscope and transmssion electron microscope for any morphological changes and then harvested for the estimation of various biochemical variables. Malondialdeyde, glutathione and antioxidant enzymes were significantly altered in the control as compared with the normal cultures. Vacuolization was also observed in the presence of galactose. Addition of lycopene confers significant protection against these changes in HLEC.