My understanding is that the light used to treat S.A.D. needs to be not only the right type, but also of sufficient intensity. Because the intensity in light boxes is very high (so you only need to be in front of it for 20 to 30 minutes), you need to be sure it is shielded for UV so it doesn't damage eyes. Here is a Mayo Clinic article on selecting a light box:
http://www.mayoclinic.com/health/sea...SECTIONGROUP=2