Cataracts
What Are Cataracts?
A cataract is a clouding of the lens of the eye. The lens is located
near the front of the eye. It focuses light on the retina, at the back
of the eye, to form the images we see.
A cataract may affect just a small part of the lens, or it may cloud the
entire lens. If your sight isn't badly impaired, the lens doesn't have
to be removed. But if the central part of the lens is cloudy, you may
not be able to see unless the lens is taken out.
Cataract Facts
- Cataracts do not spread from one eye to the other, but they may
develop in both eyes at the same time.
- A cataract is not a film on the outside of the eye.
- Cataracts are not caused by overusing your eyes, and using your
eyes doesn't make them worse.
- Cataracts usually develop over many years, not over a few
months.
- Cataracts are not related to cancer.
- Having a cataract does not lead to permanent blindness.
- Cataracts are very common, especially in older people.
Fortunately, they are treatable. Over 1.5 million cataract
operations are performed every year in North America, and in most
cases there are no complications.
Normal Eye
Eye With Cataracts
What Causes Cataracts?
There are many types of cataracts. Most are caused by a change in the
chemical makeup of the lens. Aging, certain medications (e.g. steroids),
genetics, eye injuries, or certain diseases can cause cataracts. The
normal process of aging can make the lens harden and turn cloudy. These
"age-related cataracts" are the most common, and they may occur as early
as age 40. When cataracts appear in children, they may be inherited or
they may have been caused by an infection before birth. These are called
"congenital cataracts," and babies have them at birth. Eye injuries,
such as a hard blow, puncture, cut, intense heat, or chemical burn can
damage the lens and cause "traumatic cataracts" in people of any age.
Certain diseases, such as diabetes, can cause cataracts to occur at an
earlier age. These are called "secondary cataracts."
How Are Cataracts Diagnosed?
Depending on the size and location of the cataract, you may or may not
know it is developing. If it is on the outer edge of the lens, you may
not notice a change. As cataracts develop, you may find you have a
painless blurring of your vision. Double vision may occur in one eye.
Your eyes may be more sensitive to light and glare, making it hard to
drive, especially at night. You may find that you have to change your
eyeglass prescription more often.
As the cataract gets worse, stronger glasses don't help any more. It may
help to hold objects closer when you read and do close-up work. Your
pupil may change colour and be yellowish to white.
Cataracts can't usually be seen without proper instruments. If you
notice blurred vision or other symptoms, you should see an
ophthalmologist (a medically trained eye doctor and surgeon) for a
complete eye exam. He or she will examine the inside of your eye to
determine the type, size, and location of the cataract. Your eye will be
measured for an artificial lens, which will be put into your eye during
cataract surgery. Your ophthalmologist will also tell you if you have
any other eye diseases that could affect your ability to see, even after
cataract surgery.
How Are Cataracts Treated?
When a cataract reduces your vision to the point that you can't do the
things you like to do (such as reading, driving, working on the
computer), it is probably time to have the lens removed. Surgery is the
only effective way to remove the cloudy lens. Cataracts can't be removed
with a laser. Eye drops, ointments, pills, special diets, and eye
exercises also don't work.
Most cataract operations are now performed on an outpatient basis. Local
anesthetic is used to make the operation relatively painless. The
cataract is carefully broken up and removed from the eye using very
precise and delicate instruments under an operating microscope. The
clear capsular bag that surrounds the lens is left behind, and the
surgeon then puts the artificial lens implant inside it. There are many
lens implants available; you and your ophthalmologist should discuss
which implant best suits your lifestyle.
Occasionally during surgery, the delicate capsular bag that contained
the cataract can tear and parts of the cataract may fall into the back
of the eye. If this happens, you may need a second operation to take the
rest of the cataract out. Sometimes the back of the capsular bag will
become cloudy months or even years after cataract surgery. If you notice
that your vision is reduced, laser surgery may help to restore your
vision by making an opening in the cloudy membrane.
Over 95% of patients will see an improvement in their vision after
cataract surgery. However, it is important to understand that
complications may occur and, as with any other surgery, a good result
cannot be guaranteed.
If you experience any of the following after your surgery, have your eye
checked right away:
- Pain that isn't relieved by over-the-counter pain medicine.
- Your vision gets worse, or you lose your sight altogether.
- You have an injury to your eye.
- Nausea or vomiting.
- Sudden onset of floaters or
flashing lights
© Copyright by the Canadian Ophthalmological Society