Harmful ultraviolet light from the sun causes several known conditions to occur in the eye. Sunlight has been shown to speed up the development of cataracts and macular degeneration. It can also cause abnormal thickening or growths to form on the white part of the eye. Especially people spending long time in the sun who have had cataract surgery or who are taking certain medications such as tranquilizers, tetracycline and diuretics. These drugs can cause sensitivity to sunlight. Furthermore, sunglasses reduce glare and bright light that may impede your vision and cause accidents.