A reader asks:

 Can prolonged use of a light box cause eye sensitivity and headaches? I used a light box for about two years and developed these problems.


The answer is: not that we know of. The symptoms you describe can certainly occur as short-term side effects, occurring during the use of a light box. But there is no evidence of cumulative, prolonged or delayed ocular and/or headache effects from ordinary bright light therapy usage. The combination of light sensitivity and light-aggravated headaches points in the possible direction of a migraine disorder. We suggest consulting a neurologist.