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The major avoidable cause of cataract is ultraviolet radiation ( UVR). We aimed at investigating topical caffeine in UVR-induced cataract. Topical caffeine and a placebo were applied to the eyes of separate groups of Sprague Dawley rats that were exposed to sub-doses of UVR and protective effect was evaluated. Penetration of topical caffeine in the rats to lens and blood was analysed by HPLC. Influence of topical caffeine on pupil diameter was measured in ketamine/xylazine anesthetized rats. Topically administered caffeine protected against UVR-induced cataract development with a Protection Factor, an objective relative measure of protective properties, of 1.23 and inhibited UVR-induced apoptosis. Topical caffeine peaked at 30 min in the lens, increased up to 120 min in the blood and antagonized ketamine/xylazine-induced mydriasis. Eyes treated with caffeine reacted with quick dilatation after tropicamide application. In conclusion, topically applied caffeine protects against ultraviolet radiation cataract, reducing lens sensitivity 1.23 times. Considering that caffeine is a powerful antioxidant that is easily available and well tolerated our finding implicates that caffeine may be a clinically useful anticataract agent. [ABSTRACT FROM AUTHOR]

Purpose To estimate the threshold radiant exposure for 1090 nm IRR and the time evolution of lens damage; To determine the temperature time evolution in the eye during the previously found threshold exposure, and the associated heat diffusion; To investigate if 1090 nm IRR induces cataract photochemically considering irradiance exposure time reciprocity. Methods The 6-weeks-old albino rats were anesthetized intraperitoneally, ten min before exposure. The pupils of both eyes were dilated with tropicamide. Five min after pupil dilation, the animals were unilaterally exposed to 1090 nm IRR within the pupil area. Temperature was recorded with thermocouples placed in the selected positions of the eye. At the planned post-exposure time, the animal was sacrificed and the lenses were extracted for measurements of forward light scattering and macroscopic imaging. Results The in vivo exposure to 197 W/cm2 1090 nm IRR required a minimum 8 s for cataract induction with a delayed onset of approx 16 h. The same radiant exposure was found to cause a temperature increase of 10°C at the limbus and 26°C close to the retina. The in vivo exposure to 96 W/cm2 1090 nm IRR with exposure time up to 1 h resulted in an average temperature elevation of 7°C at the limbus with the cornea humidified and no significant light scattering was induced one week after exposure. Conclusions An in vivo exposure to 197 W/cm2 IRR at 1090 nm within the pupil for 8 s induces cataract with a time delay. This threshold exposure causes a temperature rise of 10°C at the anterior segment of the rat eye. IRR at 1090 nm produces thermal cataract, probably by indirect heat conduction from absorption in tissues surrounding the lens. There is no cataract development given that the limbal temperature increase is below 8ºC. [ABSTRACT FROM AUTHOR]

Purpose To establish the resolution of measurements of the minimal distance between the central limit of the pigment epithelium and the inner limit of the retina ( PIMD) as measured with OCT. Methods The optic nerve head was topographically recorded with OCT (Topcon 3D, OCT-2000, protocol: 6 × 6 mm 3D disc cube). The minimal distance between the inner limit of the retina and the central limit of the pigment epithelium was sampled 8 times resolved in 500 angles. Results The angular minimal distance was longer in the upper and the lower meridian and averaged 0.21 mm. An analysis of the consequence of the resolution demonstrated that the minimal relevant significant average difference at α = 0.05 and aiming for β = 0.02 was 0.11 change (mm)/Average (mm). Thus, a change of 0.024 mm integrated over 2 π is the detection limit at the selected statistical parameters. This corresponds to a local average change within one quadrant of 0.006 mm. Conclusions PIMD has the potential to be a useful variable for follow-up of nerve fiber loss in the optic nerve head. [ABSTRACT FROM AUTHOR]

Purpose Ultraviolet radiation ( UVR) today is widely used in anterior segment interventions. The purpose of the study was to evaluate toxicity of UVR at 3oo nm in the rat cornea. Methods 16 Sprague Dawley rats were unilaterally exposed to 5 kJ/m2 UVR ( λmax: 300 nm; λ0.5: 10 nm) for 15 min. Contralateral eyes were kept as control. The animals were divided into 4 latency groups and eyes were taken at 1, 5, 24 and 120 h post exposure. Apoptosis was detected with the TUNEL method and histopathological changes were visualized with H&E staining. Results At 5 h post exposure all 3 exposed corneal cell layers displayed apoptotic cells with a peak at 24 h. Corneal stromal thinning and stromal neutrophil infiltration were found at 120 h in exposed corneas. Conclusions In conclusion, sterile corneal keratolysis occurs in the post exposure time window 24 to 120 h and is probably induced by neutrophils. The potential danger of sterile corneal keratolysis is to be considered in the clinical applications of UVR. [ABSTRACT FROM AUTHOR]