A cataract is an opacity or clouding of the lens inside the eye, then distorting the light as it enters. Cataracts are often confused with pterygium but cataracts cannot be seen on the surface of the eye.
Symptoms of cataract may include a gradual painless decrease in clear vision, hazy vision, increased sensitivity to glare, and even double vision.
Special tints or filters can often improve vision and UV protection can help to slow development of this condition.
The eventual cure is surgical removal of the lens with cataract and replacement with an artificial lens (intra-ocular lens implant).