Yes, too much sun cause swollen eyes actually. That is because of the stimulation and fatigue of eyes, it will get dry eye, tears, eye swollen, sore eye or blur vision symptom later if you not pay attention to this situation. This just because long time use of the eyes under the strong rays and ultraviolets. The ray shot are too dazzling to the subtle eyes tissue, it hurt the visual purple to makes color cast and hurt the visual pigments. That will make you feel dizzy and hurt ciliaris for a long time, then lead to myopia. You'd better take care you're your eyes, avoid the long time under the strongly sunshine and make sure to go out when the sunshine are in the modest rays' condition. If must go out with long time sun shining, a pair of sunglasses may useful for you.