Does your vision make you feel like you're looking through a frosted window? Are you frequently changing eyeglass prescriptions? Does the pupil of your eye appear yellowish or white? If you answered yes to any of these questions, you might have a cataract.

A cataract clouds the eye's lens and prevents light rays from reaching the retina to produce a clear image, says Dr. Hansjoerg Kolder, professor emeritus of ophthalmology at the University of Iowa College of Medicine and a staff physician at UI Hospitals and Clinics. "The eye lens itself has no blood supply, so it depends upon surrounding tissues for nutrients. If the tissues around it have poor circulation, the lens suffers and a cataract forms," Kolder says.

There are four types of cataracts: age-related, congenital, traumatic, and secondary.

Age-related cataracts, caused by the normal aging process, are the most common. Cataracts can also develop in children, however. These congenital cataracts may be hereditary or due to fetal or maternal diseases.

Traumatic cataracts result from eye injuries, such as a puncture, cut, severe blow, or exposure to toxic agents or intense heat.

Secondary cataracts are caused by diseases or infections of the eye, but also following cataract surgery.

Eye drops, ointments, and other medications have not proved successful in treating cataracts, Kolder says. The only effective way to remove a cataract is with surgery, which is usually recommended if the condition interferes with the patient's occupation and lifestyle.

During cataract surgery, the hard part of the lens, which is called the nucleus, is removed and replaced with an artificial, plastic lens. The new lens has the same optical power as the original and is about 1/4 of an inch in diameter, Kolder says. Surgery usually takes less than 30 minutes and is done on an outpatient basis, unless there are complications, such as if the patient has diabetes. "Cataract surgery is very successful. More than one million operations are done each year," Kolder adds.

After surgery, most patients return to their normal activities within a few days. Patients have to usually have return visits one day post operatively and one month later.

If you are having trouble with your vision, consult your physician or ophthalmologist.