During a conversation with Dr. Arlene Drack of the University of Iowa I learned several surprising things about protecting vision. I wanted to post these points quickly because every day we can preserve the retinas of people with BBS matters:
- Large-brimmed hats are at least as good, if not better, than sunglasses at blocking the sun’s harmful rays from retinas. Ideally people with BBS should wear both when out in the sun, but the hats are more important.
- While most of what you read about protecting vision from the potentially damaging effects of the sun is about UV rays, these are not the rays that people with BBS need to worry about. UV rays are absorbed by the lens of the eye and do not reach the retina (which is why we can’t see UV light). The danger in UV rays is that they can contribute to cataracts later in life—well after people with BBS have lost most retinal function. The rays that do damage to retinas are in the blue wavelength.
- The way to block these rays is with lenses that are brown or yellow, not the more common grey or black of most sunglasses.