Cataract Signs & Symptoms

Cataracts form painlessly. The most common symptom is cloudy or blurry vision. Everything becomes dimmer, as if seen through glasses that need cleaning. Most often, both eyes are affected, though vision is usually worse in one eye. Other symptoms include glare, halos, poor night vision, a perception that colors are faded or that objects are yellowish, and the need for brighter light when reading.

In some cases, double vision occurs. The passage of light through a lens that has irregular areas of opacity can split the rays of light from a single object and focus them on different parts of the retina, causing double vision.

Another symptom of cataracts is the need for frequent changes in eyeglass and contact lens prescriptions. The symptoms can develop over months or almost imperceptibly, over many years.

Paradoxically, in the early stages of a nuclear cataract, vision may temporarily improve in some people. For example, a person who previously needed reading glasses for presbyopia is able to read without them. This change, which is referred to as second sight, occurs because the cataract alters the shape of the lens, making it better able to focus on nearby objects. Over time, however, the improvement is lost, as the cataract's progression impairs vision.

People with cortical or posterior subcapsular cataracts often have worse vision in bright light; for example, they may have problems with night driving because of oncoming headlights. Bright light causes the pupils to contract and restricts the passage of light to the center of the lens (the part of the eye that may be most affected by the cataract).

Publication Review By: Susan B. Bressler, M.D., Harry A. Quigley, M.D., Oliver D. Schein, M.D., M.P.H.

Published: 28 Feb 2011

Last Modified: 04 Nov 2014