A reader asks:
What is the likelihood that individuals with light sensitivity (photophobia) can also have SAD? The fall/winter months have been consistently difficult for me, and I am under treatment for depression. I find that I have to wear a hat and sunglasses whenever outside (even on overcast days), otherwise I get headaches. My ophthalmologist assures me that photophobia is common to those with blue eyes (like me). Are SAD and photophobia mutually exclusive? If not, how does one treat SAD without exacerbating this disturbing side effect?
The lightly-pigmented irises of blue eyes, in comparison to brown or black eyes, admit far more photons into the eyes. Many SAD sufferers are blue-eyed. (Think Scandinavia!) Because of this sensitivity, you may find that a light therapy dose less than 10,000 lux is fully effective. That simply requires sitting at further distance from a light box rated at 10,000 lux. Photophobia may result primarily from the short-wavelength component of white light, whether outdoors or from fluorescent sources.
Apparatuses Which May Help
It is worth trying inexpensive wrap-around filters to see if they alleviate the problem. For example, NoIR sells an ultraviolet- and blue-blocking filter (noirmedical.com) which, at the 65% rating, maximizes light transmission above the short wavelengths. Another therapeutic alternative is dawn simulation (see our store), which is based on low-intensity incrementing light delivered toward the end of sleep. Even then, however, blue-eyed people often need to adjust the light level below that used by their dark-eyed counterparts.