Photoprotective effect of yellow-tinted intraocular lenses.

Purpose: The aim of this study was to experimentally investigate changes in visible light-induced photo-oxidation and to evaluate the inhibitory effect of various acrylic tinted intraocular lenses (IOLs) on photooxidation.

Methods: Three types of nontinted (VA-60BB, HOYA; SA60AT, Alcon; AU-6, Menicon) and tinted (YA-60BB, HOYA; SN60AT, Alcon; AN-6, Menicon) IOLs were used. In the first experiment, we investigated oxidation related to ultraviolet rays by using a mixed solution of reduced glutathione, nicotinamide adenine dinucleotide phosphate (NADPH), and glutathione reductase. The mixed glutathione solution was irradiated for 30, 60, or 90 min with direct artificial sunlight or artificial sunlight that had been passed through various IOLs. Oxidation was detected at 340 nm. In the second experiment, human retinal pigment epithelium (RPE) cells were prepared and cultured in a 96-well dish until confluent. After light exposure for 30 min or 48 h, lactate dehydrogenase (LDH) levels of the culture supernatant were measured to assess the amount of cell damage.

Results: Visible light-induced glutathione oxidation progressed over time. Intraocular lenses inhibited photooxidation, with the inhibitory effect shown to increase when tinted IOLs were used. LDH levels in RPE cells increased as a result of exposure to visible light. There was a higher increase in LDH with nontinted than with tinted IOLs.

Conclusion: Visible light causes photooxidation, which damages intraocular tissue in vitro. These results suggest that tinted IOLs effectively inhibit tissue damage from visible light.