What Are Cataracts?

Cataract basics

Cataracts develop naturally over time. In fact, more than half of Americans age 80 or older either have a cataract or have had cataract surgery. Except in the most developed countries, cataracts are the leading cause of blindness worldwide. If someone has a cataract, it means he has a cloudy area on the lens of his eye. How will cataracts affect a person's vision, and how can you help him cope?

The good news about cataracts

With surgery, they can be reversible.

What happens with cataracts

A cataract is a clouding of the eye's lens. Light passes through the lens (located behind the iris and the pupil) to the retina, which sends an image to the brain. If the lens isn't clear, the image reaching the retina will be blurry.

This clouding happens over time. The eye's lens is made up of protein and water, and when protein cells break down and clump together on the lens they form a cataract, causing blurred vision. If the cataract gets larger, it clouds more of the lens, making vision increasingly difficult. The lens may also become thicker and more rigid, and it may change from clear to a yellow-brown that tints what a person sees.

Cataracts are classified according to where they occur in the lens, and the type affects the symptoms a person will experience.

  • If he has a nuclear cataract, for example, it's forming in the center of the lens.
  • A subcapsular cataract appears at the back of the lens.
  • A cortical cataract occurs on the edges of the lens (but eventually sends streaks to the center of the lens).

Vision loss from age-related cataracts is most common in people over age 60, though age-related cataracts can form much earlier. Some experts think the lens changes over time because of free radicals (from smoking and ultraviolet light, for example) as well as from general wear on the protein fibers.

A person may have a cataract in one or both eyes, though it's most likely that he'll develop cataracts in both eyes.

Risk factors for cataracts

  • Age. This is the biggest risk factor.
  • Eye injury. Trauma to the eye (from a hard blow, cut, or puncture) can cause a cataract to form, sometimes years later.
  • Heredity. Those whose relatives have had cataracts are more likely to develop them.
  • Certain medications. Steroids, for example, have been linked to cataract formation.
  • Lifestyle choices. High alcohol consumption and smoking are known to increase cataract risk.
  • Some surgeries. Surgery for retinal detachment, for example, can increase risk.
  • Certain health conditions. Diabetes and high cholesterol, for example, increase risk.
  • Exposure to radiation and sunlight. Exposure to some kinds of radiation and ultraviolet rays increase risk.
What the world looks like to someone with cataracts

Imagine looking out a cloudy pane of glass. That's much like the lens of an eye with a cataract -- the picture a person sees is blurry. And the dirtier the glass (or more clouded the lens), the duller the picture.

Early on a person may not detect a difference in his vision, but if the ca taract progresses, he may notice haziness. In addition to blurred vision, he may become sensitive to glare (though he'll also need brighter light to see) or experience poor night vision or double vision.

He may need frequent changes in his glasses or contact prescription, and he may see a halo around lights. Objects may appear to have a yellow or brown cast, and he may have trouble distinguishing colors like blues and purples. Eventually he may have trouble reading.

To see an image as it might appear to someone with a cataract, go to the National Eye Institute website .

Treatment of Cataracts

No medication is available for the treatment of cataracts. In most cases, however, a simple surgical procedure can rev erse vision loss. Cataract surgery is one of the most common and safe surgeries performed in the United States, and it improves the vision of about 90 percent of those who undergo it.

The most common cataract procedure is phacoemulsification, or small-incision cataract surgery, in which the doctor inserts a small ultrasound device into the eye. The ultrasound waves soften the lens and break it up so that it can be removed by suction. The other method, called extracapsular surgery, involves making a larger incision on the side of the cornea. The doctor removes the cloudy part of the lens in one piece and then finishes removal of the lens by suction.

Once the cloudy lens is removed, it's usually replaced with an artificial lens, called an intraocular lens (IOL). If a patient can't have an artificial lens (because he has another eye disease, for example), then glasses or a soft contact lens will be used. If both eyes need cataracts removed, the eye surgeon will do the surgery on one eye at a time, usually about a month or two apart.

A cataract diagnosis doesn't necessarily mean someone needs surgery right away, though. If his vision is only a bit blurry but he can still read, drive, and perform his ordinary tasks, he may be able to get along fine for a while. And delaying the surgery normally won't make it more difficult later or cause any long-term damage.

Ways to help someone deal with cataracts without surgery:

  • Make sure that his eyeglass or contact lens prescription is as accurate as possible.
  • Help him purchase antiglare sunglasses.
  • Experiment to see what kind of lighting is best for him at home. Generally, increasing the lighting or using brighter lighting is beneficial, although glare may bother him.
  • See if a magnifying glass helps him with his reading.
  • Encourage him not to drive at night.

Some experts believe that antioxidants -- like selenium, vitamin A, and vitamins C and E -- can play a role in stemming cataract development. Ask the doctor what she thinks.

Karen Miles

Karen Miles is a regular contributor to numerous national magazines, including Woman's Day , Reader's Digest , Family Life , Family Circle , and Better Homes & Gardens , as well as to the award-winning website BabyCenter. See full bio