(HealthDay News) -- A cataract occurs when the eye's lens becomes clouded and affects vision. Cataracts can occur in both eyes, but are not spread from one eye to another.

Affecting mostly older people, cataracts can be treated with corrective lenses or surgery. According to the National Eye Institute, common symptoms include:

• Cloudy, blurry or double vision.
• Difficulty seeing at night.
• Colors appearing faded.
• Glare, sensitivity to brightness, or a halo effect around lights.
• Frequent changes to eyeglass or contact lens prescriptions.

These symptoms can indicate other eye problems, as well, and should be evaluated by a doctor, the institute says.