The lens of the eye, which is what allows us to focus, is filled with a clear protein-containing liquid. If the proteins in the liquid start to denature, they become cloudy. This can cause vision to get blurred.
Cataracts can be small and present at birth, occur (rarely) after eye injuries, and most often occur as people age, being hastened sometimes by diabetes or high blood pressure.
The radiation/ultraviolet light increase seen at high altitudes can also increase risk.
Cataracts are not dangerous, but they can impair vision.
General Diet Advice
Avoiding excess sugar can help protect the lens in your eyes by preventing the denaturing of the proteins in them.
Include a good multivitamin that optimizes antioxidant, zinc, and vitamin B2 intake. This can help prevent the denaturing of the proteins in your eye lens.
Use actual vitamin A (25,000-50,000 units a day) and not beta carotene for this.
One ophthalmologist jokingly complained that his cataract surgery income dropped by 2⁄3 when he started adding the vitamin A.
This is a high dose, and should not be used in children, people with severe liver disease, or women who might get pregnant (it can cause birth defects) — people who usually do not have cataracts anyway.
N-acetyl carnosine eyedrops (available as a product called "Can-C"). Use twice daily or follow label directions for severe cataracts.
For early cataracts, if cost is an issue I simply recommend 1 drop in each eye each morning.
Use 80 to 160 milligrams of a standardized 25% extract three times daily.
Take 3 tablets of this Chinese herbal mix daily.
Other Therapies & Advice
If you have cataracts, wear UV-blocking sunglasses on very sunny days to slow their progression.
If the cataracts remain problematic after 6-12 months of these treatments, surgery is very reasonable.
Unlike most surgery, if the cataracts are bothering you to the point you think you eventually will need the surgery (after using the above treatments), you should do the surgery sooner rather than waiting.
It is simple surgery and can markedly improve vision. So if you are going to eventually do the surgery anyway, why put up with poor vision while waiting?
Want to help people in poverty who can't afford cataract surgery?
I heartily recommend supporting the SEVA Foundation, which sends volunteer surgeons into high-altitude areas where cataracts blind millions of people unnecessarily.
For a few dollars each, they can give blind people back their sight—and have done so for over 3 million people!