The symptoms of cataracts are blurred vision, especially in bright light, and halos around light sources. Some people also experience double vision. Colors may seem drab and have a brownish tint. The person might have poor night vision and find that they need to get their eyeglass or contact lens prescription changed with increasing frequency.
The lens of a person's eye is supposed to be absolutely clear to let in light and images. A cataract occurs when the lens begins to cloud. Because the lens has no blood supply, it receives nourishment from the vitreous humor in the eye. Conditions like atherosclerosis can prevent the vitreous humor from getting its own nutrients, and this in turn affects the lens.
Cataracts are most common in older people, who are more at risk for conditions like atherosclerosis. Other risk factors for cataracts include eye injury, diabetes, eye inflammation and heredity.
Cataracts can affect one or both eyes. If both eyes are affected at the same time, the operations to remove the cataracts are scheduled at different times so the person can have some vision while the other eye heals. Cataract surgery is now done with precise mapping and lasers and is considered an outpatient procedure.