Sunburn on the eyes, also known as photokeratitis, results from excessive exposure to ultraviolet (UV) rays from sunlight or artificial sources like tanning beds. This condition affects the cornea and conjunctiva, causing pain, redness, tearing, and a gritty sensation, akin to having sand in the eyes. Prolonged UV exposure without protection, such as sunglasses or goggles, increases the risk. Symptoms usually manifest within a few hours after exposure and can last up to a few days. Prevention involves wearing UV-blocking eyewear and avoiding prolonged exposure to bright sunlight, especially at high altitudes or near reflective surfaces like water.