What is a cataract?

A cataract is a clouding of the normally clear lens of the eye. This clouding can weaken vision. The amount and pattern of cloudiness in the lens can vary.

What are the symptoms of a cataract?

Cataract is a normal aging change of the eye. Cataracts often form slowly and cause few symptoms. When symptoms are present, they can include:

  • vision that is cloudy, blurry, foggy, or filmy
  • glare or light sensitivity (especially when driving at night with oncoming headlights)
  • prescription changes in glasses (sudden nearsightedness)
  • double vision in one eye
  • need for brighter light to read
  • poor night vision
  • changes in the way you see color, especially yellow

What causes a cataract?

The eye functions much like a camera. Light rays enter through the front of the eye, passing through the cornea, the pupil, and the aqueous humor (transparent fluid in the front of the eye) onto the lens. The lens then bends light rays to focus objects onto the retina in the back of the eye. From there, the retina, the optic nerve, and the brain process the images and form vision.

Cataracts occur when there is a buildup of protein in the lens. The protein makes the lens cloudy and prevents light from passing through, which causes some loss of vision.

Cataracts can also be caused by:

  • genetic (inherited) disorders.
  • medical problems such as diabetes.
  • certain medications.
  • injury to the eye.

Other factors that increase the risk of developing cataracts include cigarette smoke, air pollution, and heavy alcohol use.

How is a cataract diagnosed?

A thorough eye examination by your eye doctor (ophthalmologist) can identify a cataract, as well as any other conditions that may be causing blurred vision.

The eye exam will tell your doctor how much vision you have lost. If there is not a great deal of vision loss, your doctor may prescribe eyeglasses (including bifocals), magnification devices, contacts, or other visual aids.

How is a cataract treated?

In the early stages of cataract development, vision may be improved simply by a change in glasses prescription. In time, as the cataract increases, blurred vision and other symptoms will not be relieved by glasses; therefore, the patient will need surgery to restore useful vision.

When should surgery be performed?

Cataract surgery should be considered when the cataract causes enough loss of vision to interfere with daily activities that are important to the patient, such as reading or driving, or recreational activities such as golf or tennis.

Occasionally, cataract surgery will be necessary to evaluate and treat other eye conditions, such as diabetic or age-related changes in the retina. Your ophthalmologist can help you with the decision about surgery under these circumstances.

How is cataract surgery performed?

Cataract surgery is performed on an outpatient basis with local anesthesia (the patient is awake but does not feel the procedure). During the surgery, the clouded lens of the eye is broken up with high-frequency sound waves or ultrasound and then suctioned from the eye by a process called phacoemulsification. The clouded lens is then replaced with a clear, plastic intraocular lens implant in order to restore vision. The power of the manmade lens is selected to fit your eye and to help restore normal vision.

Cataracts in both eyes are not removed at the same time, but will require separate surgeries.

A laser, known as the femtosecond laser, can be used for cataract surgery. This may allow for more precise outcomes.

What can I expect after surgery?

After surgery, it is normal to feel itching and some mild discomfort. Your doctor may recommend that you take a pain reliever, like Tylenol. You may also have temporary fluid discharge from your eye, and be sensitive to light for a short time after the procedure.

For a few weeks after surgery, you will need to use eye drops to aid healing, prevent infection, and control the pressure inside your eye. Strenuous activity, such as heavy lifting or activities that might lead to risk of a blow to the eye, should be avoided for several weeks. Normal non-strenuous activities, including bending, lifting, reading, and driving, can be resumed the day after surgery.

How soon will my vision improve after surgery?

Most patients will have good vision in the operated eye about a week after surgery. You may still need to wear glasses after cataract surgery.

Is cataract surgery safe?

Nearly 98% of all cataract surgeries are performed each year without serious complications. Though this type of surgery is very safe, you should discuss the risks with your ophthalmologist.

How successful is cataract surgery with lens implantation?

Cataract surgery with lens implantation is the most frequently performed surgery in the United States, with more than 1.5 million surgeries each year. More than nine out of 10 people who have cataract surgery regain excellent vision.

What are the long-term effects of cataract surgery?

Lens implants are permanent and ordinarily do not need to be replaced. They are good for the life of the patient.

In a minority of patients, a clouding occurs on the lens capsule months or years after surgery. In this case, an office procedure using a laser can open a small hole to restore normal vision.

Will insurance cover the cost of the procedure?

Cataract surgery is covered by Medicare, insurance, and HMOs.

Can cataracts be prevented?

Because the exact cause of cataracts is uncertain, there is no proven method to prevent them from forming.


© Copyright 1995-2015 The Cleveland Clinic Foundation. All rights reserved.

Can't find the health information you’re looking for?

This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 1/30/2014...#8589

Schedule an Appointment Online

Call us for an Appointment

To find a Cole Eye Institute specialist for your needs, contact us at 216.444.2020 (or toll-free 800.223.2273, ext. 42020)

Same-day Appointments

To arrange a same-day visit, call 216.444.CARE (2273)

This information is provided by Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition.

© Copyright 2015 Cleveland Clinic. All rights reserved.