I just read this article about the effect of blue LEDs on the retina and on sleep patterns. Summarizing the findings: They distinguish between acute and chronic exposure. Even chronic exposure can accelerate the aging of retinal tissue, contributing to a decline in visual acuity and certain degenerative diseases such as age-related macular degeneration. Blue LEDs interfere with body's circadian rhythm (causing sleep problems) The original report is in French, but there is an English language opinion and summary. My wife has age related macular degeneration. Fortunately, she is not a big fan of the tank and does not spend a lot of time staring at the tank. Now I won't question her indifference!