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.
Cataract is a normal aging change of the eye. Cataracts often form slowly and cause few symptoms. When symptoms are present, they can include:
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:
Other factors that increase the risk of developing cataracts include cigarette smoke, air pollution, and heavy alcohol use.
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 device s, contacts, or other visual aids.
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.
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.
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.
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.
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.
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.
Cataract surgery with lens implantation is the most frequently performed surgery, with more than 1.5 million surgeries each year. More than nine out of 10 people who have cataract surgery regain excellent vision.
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.
Cataract surgery is covered by Medicare, insurance, and HMOs.
Because the exact cause of cataracts is uncertain, there is no proven method to prevent them from forming.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or healthcare provider. Please consult your healthcare provider for advice about a specific medical condition.
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