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.
- Congenital cataracts: Babies are sometimes born with
cataracts as a result of an infection they had in the womb. Or, the
cataracts may develop during childhood.
- Secondary cataracts: These may develop as a result of
other diseases, like diabetes, or long-term exposure to toxic
substances, certain medications (such as corticosteroids or
diuretics), ultraviolet light, and radiation.
- Traumatic cataracts: These can form after injury to the
Other factors that increase the risk of developing cataracts
include cigarette smoke, air pollution, and heavy alcohol use.
What are the symptoms of cataracts?
form slowly and cause few symptoms. When symptoms are present, they
- 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
- 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 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 eye 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 severe vision loss that impairs your daily
life, you may be a candidate for cataract surgery. This surgery
involves removing the clouded lens and replacing it with a clear,
Cataract surgery, usually conducted on an outpatient basis, 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.
Can cataracts be prevented?
Because the exact cause
of cataracts is uncertain, there is no proven method to prevent
them from forming.