 Estimates of SAD prevalence range from 0.4 - 9.7 of the general population in the United States, depending on the survey methods and precise criteria used Rosen et al., 1990; Blazer et al., 1998. In addition to those with recurrent episodes of frank Major Depression, patients with less severe sub-syndromal winter depression and those with annual exacerbation of a year-round mood disorder also have been shown to benefit from light treatment in fallwinter months Kasper et al., 1989. Since the 1990s, cool-white fluorescent sources capable of yielding 10,000 lux polychromatic white light have been the treatment standard Lewy et al., 1998; Terman et al., 1998; Desan et al., 2001; also see e.g., Lam Levitt, 1999. Although well-tolerated, some transient adverse effects of the 10,000 lux white light have been reported, such as agitation or feeling wired, insomnia, headache, eye or vision problems, nausea, sedation, and chest tightness Labbate et al., 1994; Kogan et al., 1998; Terman Terman, 1999. The more common of these complaints--headache, eye or vision problems, and insomnia--remit rapidly after discontinuation of light exposure Oren et al., 1991, however, narrower bandwidth light if more potent in antidepressant effectiveness might be administered at lower intensities and thereby further reduce adverse effects and increase tolerability of the treatment Brainard, 2004. 