Blah, blah, blah . . .

About 6 percent of the U.S. population suffers from seasonal affective disorder, or SAD, a sometimes-debilitating depression that begins in the fall and continues through winter.. . .

The disorder, which is not well understood, is often treated with "light therapy," where a SAD patient spends time each morning before a bank of bright lights in an effort to trick the brain into believing that the days are not so short or dim.

A new study indicates that SAD may be linked to a genetic mutation in the eye that makes a SAD patient less sensitive to light. . .

The melanopsin gene encodes a light-sensitive protein that is found in a class of photoreceptors in the retina that are not involved with vision, but are linked to many non-visual responses, such as the control of circadian rhythms, the control of hormones, the mediation of alertness and the regulation of sleep.

I get a bit SAD at this latitude. The days are short and sometimes dim, and there's no snow blanket to reflect the limited light and make it seem brighter. I'm not disabled by it, and usually just suck it up and carry on, but in the past few years I've done some casual do-it-yourself light therapy to improve my outlook. Look on the bright side.