My son has had "red" undereye circles for much of his life but lately besides the discoloration, his undereye's have started to swell. We've always been told this is allergies but even allergy medication doesn't help. He has been on antibiotics, eye drops and nasal spray, all of which have not helped the symptoms. There seems to be some sort of light trigger, especially ultraviolet light. The swelling seems to come about rather quickly. I'm not sure what this is

There are people allergic to Ultra violet rays. Could be the redness is from him rubbing his eyes too much? Try changing the lights, sitting him away from the lights at school also or wearing head gear keeping his face out of the light. Cucumber slices on the eyes do a lot of good.

I'd take him to an ophthalmologist. Perhaps there is something rare about his tear ducts shutting down when exposed to light. Have you tried hats with brims and sunglasses, etc.