A reader asks:
What kind of light therapy would be most appropriate for a person at risk for macular degeneration? I have been seeing advertisements for green light, but my ophthalmologist is not familiar with this type of treatment.
To our knowledge, there have been no safety studies of narrow-band green light therapy, while there has there been extensive investigation of 10,000 lux broad-spectrum light therapy showing no adverse ocular events (you can download some of this literature from our website). Furthermore, thus far there have been no definitive studies showing antidepressant efficacy of narrow-band green light therapy, in contrast to positive studies of 10,000 lux broad-spectrum light. All that said, patients at risk for macular degeneration are strongly advised to use light therapy that excludes intense exposure to the short-wavelength spectrum (the blue component of white light), including such exposure from outdoor light and full-spectrum light sources. As a general guideline, lamps of 4000 Kelvin color temperature and below (soft white) are considered protective. Our recommendation would be to try broad-spectrum bright light therapy with blue-blocking wrap-arounds such as Fit-Over w/Side Shields, 65% light yellow (Eyewear Shop). A second, well-tested alternative is dimmer, incandescent illumination with dawn simulation in the bedroom. You can read about this on our website. We do suggest that you help bring your ophthalmologist up to speed on these matters, perhaps starting with the 2005 review article in the journal CNS Spectrums, also downloadable from our site.