A cataract is a clouding of the lens of the eye. This clouding can impair vision.
What causes cataracts?
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 that makes it cloudy. This prevents light from passing through a normally clear lens, causing some loss of vision. The cause of the protein buildup responsible for clouding the lens is not known.
Types of cataracts include:
- Age-related cataracts: As the name suggests, this type of cataract develops as a result of aging. Approximately 50 percent of people over age 65 have cataracts.
- Congenital cataracts: Babies are sometimes born with cataracts as a result of genetic influences or maternal illness or injury. Or, the cataracts may develop during childhood.
- Secondary cataracts: These may develop as a result of other diseases, such as diabetes, or long-term exposure to toxic substances, certain medications (such as corticosteroids), ultraviolet light, and radiation.
- Traumatic cataracts: These can form after injury to the eye.
Other factors that increase the risk of developing cataracts include cigarette smoke, air pollution, and heavy alcohol use.
What are the symptoms of cataracts?
Cataracts often form slowly and cause few symptoms. When symptoms are present, they can include:
- Vision that is cloudy, blurry, foggy, or filmy
- Sudden nearsightedness
- Changes in the way you see color, especially yellow
- Problems driving at night because oncoming headlights are distracting
- Problems with glare
- Double vision
- Sudden temporary improvement in close-up vision
How are cataracts diagnosed?
A series of simple tests performed by your eye doctor (ophthalmologist) can diagnose cataracts. An eye exam will be given to test how well you can see (remember to bring your glasses or wear your contacts). Your doctor will also dilate your pupil in order to examine the condition of the lens and other parts of the eye.
How are cataracts treated?
The eye exam will tell your doctor how much vision loss is present. If the loss is minimal, your doctor may prescribe eyeglasses (including bifocals), magnification devices, contacts, or other visual aids.
If you suffer from vision loss which impairs activities that are important to you, you may be a candidate for cataract surgery. This surgery involves removing the clouded lens and replacing it with a clear, plastic one.
Cataract surgery is usually conducted on an outpatient basis and is very successful in restoring vision. In fact, it is the most frequently performed surgery in the United States, with more than 1.5 million cataract surgeries each year. More than nine out of 10 people who have cataract surgery regain excellent vision.
Talk to your doctor to see which treatment is right for you.
What happens during cataract surgery?
During cataract surgery, the affected lens is removed and replaced with a plastic, clear lens. There are different surgical techniques used to remove the lens. One method is called "phacoemulsification." Under local anesthesia, a surgeon uses high-frequency sound waves or ultrasound to break the lens into small pieces. The pieces are removed by suction through a small incision in the eye.
After the clouded lens is removed, it may be replaced with a new, manmade lens called an intraocular lens. This procedure is called "intraocular lens implantation." The power of the manmade lens is selected to fit your eye and to help restore normal vision. You may still need to wear glasses to maximize your vision after cataract surgery.
Because cataract surgery is usually performed on an outpatient basis, you will not have to stay in the hospital. Cataracts in both eyes are not removed at the same time, but will require separate surgeries.
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.
What can I expect after surgery?
After surgery, it is normal to feel itching and some mild discomfort. To combat this, 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 following the procedure.
For a few days after surgery, you will need to take medication in the form of eye drops to aid healing, prevent infection, and control the pressure inside your eye. Your surgeon may want you to avoid very strenuous activities for a short period after surgery, but most normal activities need not be restricted.
How soon will my vision improve after surgery?
Vision usually improves the day after surgery. Maximum improvement usually comes when new glasses are prescribed, about a month after surgery.
What are the long-term effects of cataract surgery?
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. Lens implants are permanent and ordinarily do not need to be replaced. They are good for the life of the patient.
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.