Most of the time, doctors can tell you have photokeratitis just by asking you about your recent activities, and looking at your eyes after they apply special drops . When your unprotected eyeballs get exposed to UV rays, it damages your cornea and conjunctiva, which leads to a whole bunch of uncomfortable symptoms. Most people report pain, redness, blurry vision, swelling, light sensitivity, twitching eyelids, and (as Busy described in excruciating detail) a gritty sensation in the eyes , according to the Cleveland Clinic. The symptoms usually go away between six hours and a day, but they can also last for up to two days.