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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 isnÕt badly impaired, the lens doesnÕt 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. 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 Òage-related cataractsÓ 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 Òcongenital cataracts,Ó 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 Òtraumatic cataractsÓ in people of any age. Certain diseases, such as diabetes, can cause cataracts to occur at an earlier age. These are called Òsecondary cataracts.Ó 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 donÕt 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 canÕt 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. When a cataract reduces your vision to the point that you canÕt 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 canÕt be removed with a laser. Eye drops, ointments, pills, special diets, and eye exercises also donÕt 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. Over 95 per cent 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.
