General Information About 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.

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 vs Eye with Cataract Comparison showing the difference between a healthy eye and an eye with a Cataract

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:

Information Courtesy of:
Canadian Ophthalmological Society
1525 Carling Avenue, Suite 610
Ottawa, Ontario Canada K1Z 8R9