How Do Cataracts Affect the Eyes?

As explained earlier, all light entering the eye passes through the lens. Your lens must be clear for light to focus properly on the retina. Therefore, any clouding of the lens will affect your vision to some extent.

In most people, cataracts develop gradually and their eyesight may be adequate for several years before surgery is necessary. Other people experience more-rapid progression of cataracts, especially if several areas of the lens are affected. Cataracts that form directly behind the pupil are likely to cause problems sooner than cataracts closer to the edges of the lens.

As more and more of the lens becomes opaque, the clouded areas scatter the light that enters and prevent it from focusing properly on the retina. If you have cataracts, sensitivity to glare might make it hard to drive at night. You might see halos around lights. Your vision might be blurred or hazy-like trying to see through a waterfall. (In fact, it might be that sensation that gave cataracts their name: The Latin term for "waterfall" is cataracta. Another theory is that the whitish color of an eye cataract is similar to the color of turbulent water, as in a waterfall.)

Eventually, the lens takes on a yellow or brown tinge, which affects your ability to distinguish colors, particularly shades of purple and blue. Again, these changes might occur so slowly that you don't notice them until someone points out that your socks don't match!

Age-related cataracts don't spread from one eye to the other, though they typically develop at about the same rate in both eyes. Cataracts, if neglected, can advance to the point where the pupils appear milky. These cataracts are referred to as ripe or mature. (At one time, patients were advised to wait until their cataracts were ripe before having surgery. This approach was abandoned long ago.)

Immature cataracts, in which there are still clear areas of the lens, are generally not visible except to the doctor who is examining your eyes. You would almost surely notice significant vision changes and seek treatment long before your cataracts were ripe and visible to the naked eye.

Unless they are persistently ignored and become overripe, cataracts do not cause discomfort-itching, burning, or aching-or a discharge from your eye, nor do they create redness, swelling, or inflammation. If you have symptoms such as these, see your eye doctor to find out what is causing them.

Can Cataracts Cause Blindness?
With continued neglect, a cataract may turn completely white and become painful and inflamed. Described as overripe or hypermature, these cataracts are so advanced that the patient has little or no vision in the affected eye. Surgery is essential to remove the inflamed lens. This surgery is more difficult and recovery takes longer than the usual lens-replacement procedure.

Only if you ignore them and fail to get proper treatment are cataracts likely to cause blindness. Many people, unfortunately, do not receive treatment, which is why cataracts are the most common cause of blindness worldwide.

There are a variety of reasons that cataracts go untreated: In some parts of the world, safe and effective cataract surgery is not readily available. Even in the United States and other developed nations, however, many people are afraid to see a doctor about their failing vision. Some of them fear surgery, not realizing that lens replacement is a quick and virtually painless outpatient procedure with a very high success rate.

We've touched on signs and symptoms of cataracts. The next chapter will discuss these symptoms in greater detail and will help you and your doctor decide when it's time to consider surgery for your cataracts.