Iprgc

ipRGC

ipRGC stands for intrinsically photosensitive retinal ganglion cell, a special type of nerve cell in the eye that detects light on its own. Unlike the rods and cones that let you see shapes and color, these cells respond directly to brightness using a light-sensitive pigment. They send information to brain centers that control daily biological rhythms, pupil size, and other non-visual responses to light. Because they are tuned to overall light level and especially to blue wavelengths, they play a major role in how light affects sleep, alertness, and hormone cycles. These cells matter because they link what you see with how your body times important processes. When ipRGCs sense light at the wrong time of day — for example from screens at night — they can delay sleepiness and change hormone patterns. Damage or loss of these cells, which can occur with aging or eye disease, may lead to sleep disturbances and changes in daytime alertness. Understanding ipRGCs helps designers create lighting that supports healthy sleep patterns, and it helps doctors think about how eye health connects to overall wellbeing.