Not just the Sun, but any bright light. It's weird though, because the better of a mood I'm in, the brighter my eyes get. Sounds jacked-up, I know. I might sneeze from light maybe a few time per day. I actually try to avoid light because of the sensitivity. I keep my curtains closed most of the time, and depending how bright it is, I won't go out until later in the evening. If I shut my eyes, I can actually walk around my room and in the hallway without hitting anything. When it is night time and the lights are all out, I can see things in detail, eyes open of course. So, I am able to get around at night just fine. lol