What is a Cataract?

A cataract is a loss of transparency, or clouding, of the lens of the eye. The lens is normally crystal clear. With time, chemical changes occur in the lens that make it cloudy. This is when the lens is called a cataract. The age of onset varies. Rarely, babies can be born with cataracts, but in most individuals, the cloudiness begins in adulthood.

There are many patterns of cloudiness; the most common pattern is a diffuse cloudiness. Early on, the loss of transparency is mild and the vision is hardly affected. The cloudiness progresses at varying rates depending on the individual. In time, the cloudiness can get so severe that no shapes or movements are seen, only light and dark. Removal is recommended when the vision is affected by the cataract to the point that it interferes with the patient's activities and lifestyle.

A cataract will typically cause a slow, progressive, painless decrease in vision and can be asymmetric. Other possible changes include glare or haloes, particularly with night driving; trouble reading or making out fine details; frequent eyeglass prescription changes; a decrease in colour intensity and a yellowing of images.

Glasses or contact lenses can help sharpen your vision somewhat if an early cataract is present, but as the clouding progresses, they will no longer be helpful. Your lifestyle and activities will also determine how soon the cataracts affect your lifestyle. Removal of the cataract is recommended when the vision is affected by the cataract to the point that it interferes with the patient's activities and lifestyle, and updating the corrective lenses does not improve the symptoms.

As the lens gets harder, farsighted or hyperopic people may initially experience improved distance vision and less dependence on glasses. However, nearsighted or myopic people may become more nearsighted or myopic, causing distance vision to be worse. Some types of cataracts affect distance vision more than reading vision. Others affect reading vision more than distance vision.

The most common cause of cataract is aging. Other causes include trauma, eye rubbing, medications such as steroids, systemic diseases such as diabetes and prolonged exposure to ultraviolet light. There are many different types of cataracts, and they can develop at any age.

Controlling these risk factors can reduce your risk of developing a cataract but once developed there is no cure except to have the cataract surgically removed.

Outpatient surgical procedures can remove the cataract through either a small incision (phacoemulsification) or a large incision (extracapsular extraction).

The time to have surgery is when your vision is affected enough to interfere with your lifestyle. Your surgeon and you make the decision as a team. The surgeon’s role is to confirm that you have a cataract affecting your vision and that surgery to improve the vision is appropriate. Your job as the patient is to consider the risks and benefits as presented to you by your surgeon, and to have the desire to undergo surgery. It is no longer necessary, or desirable, to wait until the cataract is “ripe”. That was done years ago, when surgical techniques were very different from those that are used now.

Cataract surgery is in general a very successful operation. Millions of people have this procedure every year all over the world. As with any surgical procedure, complications can occur during or after surgery and very rarely, some are severe enough to limit vision. But in most cases, vision, as well as quality of life, improves.