With every sunrise and sunset, our eyes make note of the light as it waxes and wanes, a process that is critical to aligning our circadian rhythms to match the solar day so we are alert during the day and restful at night. Watching the sun come and go sounds like a peaceful process, but scientists have discovered that behind the scenes, millions of specialized cells in our eyes are fighting for their lives to help the retina set the stage to keep our internal clocks ticking.

Source: Turf battle in retina helps internal clocks see the light