Abstract
Purpose: :
To evaluate the protective effects of currently available, foldable, clear, and yellow-tinted intraocular lenses (IOLs) against possible retinal damage by sunlight.
Methods: :
Fifty-four IOLs including three clear IOLs (SA60AT, Alcon; VA-60BBR, Hoya; and AU6K, Kowa) and three yellow-tinted IOLs (SN60AT, YA-60BBR, and AU6N) with three different lens powers (+10, +20, and +30 diopters). The spectral transmittance in the wavelength range of 300 to 800 nm was measured using a spectrophotometer through 2.5 and 4.5-mm diameter apertures, and the retinal hazard indexes including blue-light irradiance (BLI) and maximum permissible exposure duration per day (Tmax) for viewing the sunlight were calculated.
Results: :
The clear IOLs completely absorbed the ultraviolet (UV) light and nearly completely transmitted the visible light at wavelengths longer than 440 nm. Yellow-tinted IOLs absorbed more in the blue-light range (400-500 nm) than clear IOLs. All IOLs had lower BLI values and longer Tmax values compared to aphakic eyes (15.00 mW/cm2 and 0.67 second, respectively), and all yellow-tinted IOLs had lower BLI values (2.68-4.55 mW/cm2) and longer Tmax values (2.20-3.73 seconds) compared to phakic eyes (5.76 mW/cm2 and 1.73 seconds, respectively). When comparing the BLI values of the clear and yellow-tinted IOLs, the BLI of the SN60AT IOL was 34.2% to 56.0% lower than that of the SA60AT IOL, the BLI of the YA-60BBR IOL was 35.2% to 48.4% lower than that of the VA-60BBR IOL, and the BLI of the AU6N IOL was 16.8% to 22.9% of the AU6K IOL. The BLI values of the SN60AT and YA-60BBR IOLs decreased as the lens power increased. When the two aperture diameters were tested, the BLI values generally did not differ between the measurements.
Conclusions: :
Compared to aphakic eyes, UV-blocking clear IOLs reduce the BLI value by 60% and the yellow-tinted IOLs confer an additional 17% to 56% reduction in the BLI. The difference in the lens power is significantly related to the BLI value in some yellow-tinted IOLs.
Keywords: intraocular lens • retina • protective mechanisms