A Cataract is the clouding of the eye’s lens, often part of the aging process. The eye lens is a transparent structure that focuses images on the light sensitive area of the eye called the retina. When we look at something the light rays travel into our eye through the pupil, or the opening in the iris, and are focused through the eye’s lens onto the retina. Cataracts occur when certain proteins in the lens form abnormal clumps and these clumps get larger and interfere with vision. If the lens becomes cloudy due to these clumps, the light cannot focus clearly on the retina, this cloudy lens is referred to as a cataract. Because the light is no longer focused on the retina correctly, your vision may become blurry, dulled, or cloudy. A cataract can develop in one or both of your eyes. Patients often refer to their vision of cataracts as looking through a dirty window, or looking through a waterfall. While cataracts are often related to aging, they may be caused by eye trauma, long-term diabetes, corticosteroid medications, or radiation treatments. In infants cataracts can be seen since birth or occur as a result of an infection that happened during pregnancy, especially toxoplasmosis, cytomegalovirus, rubella, syphilis, or herpes simplex. Commonly, cataracts are treated with cataract surgery. For more information please visit the American Academy of Ophthalmology article on Cataracts

Clear versus cloudy lense. Kierstan Boyd "What are Cataracts" American Academy of Ophthalmology

Clear versus cloudy lense.
Kierstan Boyd
“What are Cataracts”
American Academy of Ophthalmology