Q: What are cataracts made of and what causes them to form in the eyes?
A: Cataracts are made of the same soluble proteins and water that are found in the normal lenses of the eyes, but arranged differently so that they interfere with the path of light, clouding vision and scattering light.
The lens forms in the uterus and its protein strands are not equipped with cellular mechanisms for cleanup and repair. With age, the proteins may become misfolded and clump together, according to a 2012 review article in the journal Trends in Molecular Medicine.
Chaperone proteins that keep the strands in order can fail, and the strands are also subject to chemical processes, including oxidation, that can change their color. Researchers have found several possible causes for the deterioration and jumbling of the proteins, with much recent work focusing on the effects of ultraviolet A and B radiation.
A 2014 study in The Journal of Biological Chemistry outlined the chemical changes suspected to take place upon prolonged exposure to such rays. Other risk factors for cataracts include some diseases, like diabetes, as well as smoking and excessive use of alcohol.