Gary L. Morgan, OD, focuses his blog on AMD prevention, strategies for monitoring patients with AMD, the effects of blue light on the retina and mitigating the unforeseen effects of technology on vision and overall health. He is in private practice at Eye Tech Associates in Arizona.

Disclosure: Morgan is an advisory board member for Arctic Dx, MacuHealth and Signet Armorlite.

BLOG: Become your community's blue light expert

In my last post I discussed that awareness of blue light is growing among our patients.

Mainstream media stories are taking on the subject of blue light and its health consequences head on. I have seen stories in the lay press regarding blue light and age-related macular degeneration, blue light and visual performance and, just recently, a piece on blue light and sleep disturbance.  On April 9, ABC News’ Good Morning America ran a piece on wearing “orange-tinted glasses” before bed when looking at electronic devices. While overall the piece was well done, there was something that was unsettling to me.

The story centered on a recently published study in the Journal of Adolescent Health. In the study, 13 15- to 17-year-old healthy boys were followed for a 2-week period. The authors wanted to investigate whether wearing blue light-blocking glasses, particularly lenses that block blue light within the circadian action spectra (460 nm to 480 nm), would have an effect on sleep-initiating mechanisms.

Subjects were exposed to LED screens while either wearing clear lenses or blue-blocking lenses. Measures of melatonin secretion, vigilant attention/sleepiness and sleep were measured. Results showed significantly more melatonin secreted for the blue light-blocking lenses group along with feeling significantly sleepier at bedtime. Sleep quality between the two groups was not statistically different, although the authors acknowledge that the 1-week trial may not have been long enough to alter circadian rhythm.

An important point I picked up on in reading this study is that the authors found that blue-blocking lenses only modified vigilant attention and subjective sleepiness in the evening before sleep but not the morning after. In other words, when the investigators had subjects wear blue-blocking lenses the next morning vs. wearing clear lenses, there was no measured difference in sleepiness or alertness. I find this striking because, as of late, I have seen promulgated that wearing blue-filtering lenses throughout the day will cause sleepiness and decreased alertness.