In his book Health and Light, Dr. Ott* argues that the body needs exposure to the full spectrum of light through the eyes in order to stimulate the immune system and other body functions. He therefore recommends that a hat rather than sunglasses should be worn on sunny days, and that sunglasses should only be worn in conditions of high glare.

Dr Jacob Liberman agrees. He suggests that our indoors lifestyle "coupled with our excessive use of sunglasses may be blocking out the ultraviolet (UV) radiation necessary for normal cell division, thus resulting in certain degenerative eye diseases such as macular degeneration”. He dismisses the 1982 study by W.T. Ham et al., which led a generation of eye specialists to conclude that any UV radiation is harmful to the eye, because its finding of damage from UV was based on clamping monkeys’ eyes open (no blinking) and exposing them to levels and durations which would never occur naturally (Light: medicine of the future. Santa Fe, New Mexico, Bear & Co. 1991).

Ed.- Dr Ott also reports that children exposed to full spectrum fluorescent lighting suffered far fewer tooth cavities compared to those taught in classrooms with normal fluorescent tubes (New Scientist 6.4.91 p13) and that a 1939 study found a direct link between reduced cavity levels and increased exposure to sunshine for children (American Journal of Public Health 1939; 29:777 and Journal of Nutrition 1938;15:547).

* of the Wills Eye Hospital, Philadelphia, US