On 27 Feb 2003, Harry Avis wrote: > A student asked a question today that I should know the answer to, but > I don't. I am in the process of clearing out my office as I am > retiring and can't find a source. The question: Is it true that blue > eyed people are more sensitive to light than brown eyed?. I can figure > out that blue eyed people usually have a light skin color and are more > sensitive to ultraviolet, but this question specifically referred to > eye color and sensitivity to light in the visual system. Any help for > geezers having a senior moment? >
Off the top of my head, yes, it's true. Eye colour is, strangely enough, dependent on the amount and distribution of only one pigment in the iris. The more you have of it, the darker your eye colour. Those will blue eyes have relatively little (the blue colour comes from the scattering of light when reflected from the eye, same as for the sky). As a result, I believe that ol' blue eyes are more at risk for vision disorders dependent on sun exposure such as cataract and macular degeneration. Me, I squint a lot in the sun (and eat spinach every day (really!)) for its lutein content to build up the pigment epithelium in the retina. There isn't yet direct evidence that it protects against macular degeneration, but some promising indirect. So I figure a little spinach (and orange peppers, and corn, and squash) can't help (a bout of a transient condition a few years ago similar to macular degeneration scared me into it, which I think was caused by staring at the setting sun. Dumb move.) Stephen ______________________________________________________________ Stephen L. Black, Ph.D. tel: (819) 822-9600 ext 2470 Department of Psychology fax: (819) 822-9661 Bishop's University e-mail: [EMAIL PROTECTED] Lennoxville, QC J1M 1Z7 Canada Dept web page at http://www.ubishops.ca/ccc/div/soc/psy TIPS discussion list for psychology teachers at http://www.frostburg.edu/dept/psyc/southerly/tips _________________________________________________________ --- You are currently subscribed to tips as: [EMAIL PROTECTED] To unsubscribe send a blank email to [EMAIL PROTECTED]
