May 26, 2004
IOL protection rating
Eyeworld May 2004
The retinal protection factor (RPF), developed by Gary Hall, M.D., of Phoenix, Ariz., rates IOLs for their solar protective value in terms of retinal protection from UV and blue light.The RPF rating system is a derivative of another system Hall developed over the last 10 years to rank the solar eye protection factor (EPF) of sunglasses. The RPF was based on the same data Hall collected for the EPF system, with some modifications.Intraocular lenses are easier to rate than sunglasses, because they only potentially shield the retina as opposed to the entire eye. Hall’s analysis found three of the five lenses tested allowed some transmittance of highly toxic UV radiation to the retina: The AMO AR40e and Phacoflex II SI40NB (Advanced Medical Optics, Santa Ana, Calif.) and the AcrySof MA60BM (Alcon, Fort Worth, Texas).The CeeOn 911A (Pfizer Ophthalmics, New York, N.Y.) and Alcon’s AcrySof Natural blocked 100% of UV light. The other component of the overall RPF was an analysis of the blue light that the lens transmitted. Hall found the blue light factor ranged from the worst for the AMO AR40e and the best performance by the AcrySof Natural.. The significance of the blue light rating was based upon further calculations and deduction. Acceptance of the danger from UV is at least partially based on the understanding that the retina is about five times as sensitive to UV over the entire spectrum of UVA than it is to blue light over the entire spectrum.However, because only 1.3% of UV transmits to the retina, while 60% of blue transmits to the retina, and there is about twice as much blue in the earth’s environment as there is UV, therefore, blue light is more toxic to the retina than UV.But Mainster had problems with Hall’s IOL rating system for several reasons....
Posted by mehdi khanlari at May 26, 2004 04:31 PM