New approach to evaluate retinal protection by intraocular lenses against age-related lipofuscin accumulation-mediated retinal phototoxicity.

PURPOSE: To present a new approach for evaluating intraocular lenses (IOLs) for retinal protection from age-related lipofuscin accumulation-mediated phototoxicity.

SETTING

Alcon Laboratories Inc., Fort Worth, Texas, USA, and Cardiff University, Cardiff, United Kingdom.

METHODS

Age-related lipofuscin accumulation-mediated action spectra for retinal phototoxicity in an aphakic eye were created for this evaluation. Transmission curves for 6 IOLs and for cornea and spectral radiant power distribution for sunlight and 2 lamps were used. Pseudophakic action spectra and retinal phototoxicity for 3 wavelength ranges and 3 ages were computed. The percentage protection of each IOL was computed as the reduction in phototoxicity relative to the aphakic eye.

RESULTS

Retinal phototoxicity increased 3.66 times from the third to ninth decade of age. The comparative retinal phototoxicity and retinal protection provided by IOLs were dependent on the light source and range of wavelength; however, unlike phototoxicity, retinal protection was independent of age. The 420 to 480 nm range was the most useful for discriminating protection by IOLs.

CONCLUSIONS

Retinal phototoxicity significantly increased with age; however, the retinal protection by IOLs was independent of age. The interaction between the transmission curve of IOLs and light sources required inclusion of widely used lamps besides sunlight for evaluation of IOLs. For the 420 to 480 nm wavelength range, the 3 light sources clearly discriminated the protection provided by IOLs. The AcrySof Natural IOL (Alcon) provided the highest protection consistently for the tested light sources.