Blue light-filtering IOL may be beneficial

October 15, 2005

Montr?al—The blue light-filtering effects in the AcrySof Natural ultraviolet (UV) IOL (Alcon Laboratories) significantly reduce apoptosis of retinal pigment epithelium (RPE) cells induced by blue light compared with the conventional AcrySof filter lens. Implantation of a lens with a blue filter may be beneficial for patients who are at increased risk for the development of macular degeneration.

"There is evidence that exposure to blue light may play a role in the development and progression of macular degeneration. With increasing age, the human lens develops an increasingly yellow color. This may be a naturally occurring factor that reduces the exposure of the retina to blue light," said Kourous A. Rezaei, MD, who spoke at the American Society of Retina Specialists meeting in Montréal. "After cataract surgery, however, implanted lenses filter only UV light because of the ultraviolet chromophore in the lens. The Natural lens also has a blue light-filtering chromophore."

Blue light is well known to cause apoptosis of RPE cells. With that in mind, Dr. Rezaei and colleagues compared the filtering effect of the AcrySof Natural UV lens with that of the conventional AcrySof UV lens on blue light-induced cell death in the RPE. Dr. Rezaei is assistant professor, ophthalmology and visual science, and director, vitreoretinal service, department of ophthalmology and visual science, University of Chicago.

"The RPE cells that were covered with the AcrySof Natural lens and exposed to blue light maintained their monolayer morphology. The RPE cells that were covered by the AcrySof UV lens no longer had a tight monolayer, and most of the cells died," Dr. Rezaei reported.

"Our results indicate and confirm previous findings that blue light induces significant apoptosis in RPE cells compared with the cells that were not exposed to light. Use of the AcrySof Natural filter significantly reduced the blue light-induced apoptosis compared with the conventional AcrySof lens. The amount of blue light energy that reached the cells with the AcrySof filter was 4.25 mW/cm2 and with the AcrySof Natural filter was 2.5 mW/cm2," Dr. Rezaei said.

"The AcrySof Natural filter lens, which has a blue light-filtering chromophore, significantly reduces blue light-induced apoptosis compared with the AcrySof filter lens," he said.

"This result is most likely due to the filtering effect on the blue light, which would reduce the energy that reaches the RPE cells. These results further confirm that during cataract surgery, implantation of a lens with a blue light-filtering chromophore may be warranted for patients who are at risk for development of macular degeneration," he concluded.