A reader asks:

 Is light therapy safe for the eyes?


The largest study, for 10,000 lux, 30 min daily exposures for up to 6 winters, was reported in the American Journal of Ophthalmology (for a download, go to Dr. Gallin’s paper in the SAD section of Treasury of the Literature, under the EDUCATION tab at the top of the page). No ocular abnormalities occurred. The authors concluded that light therapy “appears safe for the eyes. Current knowledge is insufficient to specify any definite ocular contra-indications for bright light therapy, although we recommend that patients with preexisting ocular abnormalities and those using photosensitizing drugs undergo treatment only with periodic ophthalmologic examination.” Although there are no definite countraindications, we also recommend that alternatives to light therapy be used by patients with retinal degenerative disease.