What Are Cataracts?
A cataract is a clouding of the eye varying in intensity from a slight opacity to the complete obstruction of light. Cataracts cause blurry vision or changes in the clarity and color of vision, often causing a gradual yellowing of the eye that can at times cause a problem perceiving the color blue.
Cataracts result when there is clouding on the lens of the eye due to the clumping of proteins. A cataract makes the lens cloudy, and when light travels through the cloudy lens to reach the retina, a blurry image results. Contrast sensitivity can also be lost, meaning that shadows, contours, and colors become less vivid.
Different types of cataracts have different causes, but many people get them simply because of age and oxidative stress. Oxidative stress occurs when free radicals in the body damage cells, including proteins. In addition to aging, cataracts can also be brought about by smoking and diseases such as diabetes, both of which contribute to oxidative stress in the body.
Cataracts can also be caused by exposure to radiation, hypertension, eye injury, or physical trauma, or can be hereditary. Cataracts are also common to certain occupations — glassblowers and airline pilots both have unusually high likelihood of developing cataracts because they are both exposed to unusual amounts of radiation.