What is cataract?

Q: My mother was told she has a cataract in her eye. What is this and what can be done about it?

A: Cataract is the leading cause of reversible blindness in the world. It is a very common cause of blurred vision here in the CNMI.

When the natural lens of the eye gets cloudy it’s called a “cataract.” Cataracts occur most commonly as a result of aging. Almost all of us will eventually get cataracts. But you can also get cataracts at younger ages. They occur at younger ages in people with diabetes, trauma and a few other conditions. Let’s take a quick tour of the eye to better understand cataracts. You may follow along on the drawing.

Light comes into the eye through the cornea, that clear covering over the brown or blue part of the eye (which is called the iris). Next the light passes through the black hole that is in the middle of the iris, which is called the pupil. Right behind the pupil is the lens which gets cloudy and becomes a cataract.

After the light passes through the cornea, the pupil and the lens, it passes through the large space inside the eye and lands on the retina. The retina is a thin layer of nerves and blood vessels that coats the inside of the eyeball, and it changes the light into electricity.

The electrical signal then goes down the nerve and back to the brain. I tell my patients that all these parts need to work well for us to see clearly. A problem with any part will disrupt the vision.

In some ways, the eye is like a camera. The cornea, pupil and lens are focusing the light; the retina is like the film inside the camera; and the nerve and the brain are developing the pictures.

The reason you do not see well when you have a cataract is that the lens inside the eye has gotten cloudy. When the lens gets cloudy, light cannot get to the back of the eye, and the vision gets blurry. It’s a little bit like the window of a house getting cloudy—we just can’t see out any more.

When the lens gets cloudy, glasses cannot help much, medicine cannot help, and eye drops cannot help. But there is a very good treatment available for cataracts, and that’s to take the cloudy lens out and replace it with a new clear artificial lens. When the lens gets cloudy, it’s called a “cataract” and the procedure we use to fix it is called “cataract surgery”.

When most people hear about surgery, especially on the eye, they get scared. I tell my patients that for you, the operation is very easy. You come in on your scheduled day, you get the surgery, and you go home the same day. The surgery takes about half and hour, and we don’t even have to put you to sleep. We give you some medicine to help you relax, some eye drops to numb the eye and there is almost always no pain at all. The day after the surgery you can go back to your regular activities, so there isn’t much disruption to your schedule or your lifestyle. Of course the surgery is very delicate and needs a skilled ophthalmologist to perform it.

Most people are amazed by the clarity of vision after their cataracts are removed. The surgery is one of the miracles of modern medicine, because we can take someone who is blind from cataracts and give them all their sight back. It’s one of those operations where my patients come in the day after the surgery with a big smile and throw their arms around me. That’s why I enjoy doing the surgery so much. If your vision is blurry in one or both eyes, it may be cataracts. And the cataract surgery, a miracle of modern medicine, can give you all your vision back.

(David Khorram, MD is a board certified ophthalmologist, and director of Marianas Eye Institute. Questions and comments are welcome. Call 235-9090 or email eye@vzpacifica.net. Copyright © 2006 David Khorram.)