05/01/2026
What are cataracts?
A cataract is a clouding of the clear lens inside your eye. This cloudiness blocks light from reaching the back of the eye, making it harder to see clearly. A cataract can affect one or both eyes, but it doesn't spread from one eye to the other.
Cataracts usually develop slowly. As they get worse, your vision can become blurry or dim. Brighter lighting or new eyeglasses may help at first, but if cataracts begin to interfere with your daily activities, you may need cataract surgery.
Without treatment, cataracts can cause severe or even permanent loss of vision.
What causes cataracts?
Most cataracts develop as part of the normal aging process. This happens when the protein in the lens of your eye clumps together. Over time, these protein clumps grow larger and thicker, making it harder to see. The lens may turn yellow or brown, which can affect how you see colors.
Cataracts can also develop after an eye injury or surgery for another eye condition, like glaucoma.
A cataract is a clouding of the lens in your eye. It affects your vision. Cataracts are very common in older people. Learn about symptoms and surgery.