What are Cateracts?
What are Cataracts?

A cataract is a clouding of the normally clear lens of your eye. For people who have cataracts, seeing through cloudy lenses is a bit like looking through a frosty or fogged-up window.

Clouded vision caused by cataracts can make it more difficult to read, drive a car (especially at night) or see the expression on a friend's face.

Most cataracts develop slowly and do not disturb your eyesight early on. But with time, cataracts will eventually interfere with your vision.

At first, stronger lighting and eyeglasses can help you deal with cataracts. But if impaired vision interferes with your usual activities, you might need cataract surgery. Fortunately, cataract surgery is generally a safe, effective procedure.

Causes

Most cataracts develop when aging or injury changes the tissue that makes up your eye lenses.

Some cataracts are related to inherited genetic disorders that cause other health problems and increase your risk of cataracts. Cataracts can also be caused by other eye conditions, medical conditions such as diabetes, trauma or past eye surgery. Long-term use of steroid medications, too, can cause cataracts to develop.

How a cataract forms

The lens, where cataracts form, is positioned behind the colored part of your eye (iris). The lens focuses light that passes into your eye, producing clear, sharp images on the retina; the light-sensitive membrane on the back inside wall of your eyeball that functions like the film of a camera.

A cataract scatters the light as it passes through the lens, preventing a sharply defined image from reaching your retina. As a result, your vision becomes blurred.

As you age, the lenses in your eyes become less flexible, less transparent and thicker. Age-related changes cause tissues within the lens to break down and clump together, clouding small areas within the lens. As the cataract continues to develop, the clouding becomes denser and involves a greater part of the lens.
Cataracts may develop in only one eye, but they usually develop in both of your eyes. However, the cataracts usually are not totally symmetrical, and the cataract in one eye may be more advanced than the other.

Types of cataracts

Cataract types include:

Cataracts that affect the center of the lens (nuclear cataracts). A nuclear cataract may at first cause you to become more nearsighted or even experience a temporary improvement in your reading vision. But with time, the lens gradually turns more densely yellow and further clouds your vision.

As the cataract slowly progresses, the lens may even turn brown. Advanced yellowing or browning of the lens can lead to difficulty distinguishing between shades of color.

Cataracts that affect the edges of the lens (cortical cataracts). A cortical cataract begins as whitish, wedge-shaped opacities or streaks on the outer edge of the lens cortex.
As it slowly progresses, the streaks extend to the center and interfere with light passing through the center of the lens. People with cortical cataracts often experience problems with glare.

Cataracts that affect the back of the lens (posterior subcapsular cataracts). A posterior subcapsular cataract starts as a small, opaque area that usually forms near the back of the lens, right in the path of light on its way to the retina.

A posterior subcapsular cataract often interferes with your reading vision, reduces your vision in bright light, and causes glare or halos around lights at night.

Cataracts you're born with (congenital cataracts). Some people are born with cataracts or develop them during childhood. Such cataracts may be the result of the mother having contracted an infection during pregnancy.

These cataracts also may be due to certain conditions, such as myotonic dystrophy, galactosemia, Lowe's syndrome or rubella. Congenital cataracts don't always affect vision, but if they do they are usually removed soon after detection.

Symptoms

Signs and symptoms of cataracts include:

Clouded, blurred or dim vision
Increasing difficulty with vision at night
Sensitivity to light and glare
Seeing "halos" around lights
Frequent changes in eyeglass or contact lens prescription
Fading or yellowing of colors
Double vision in a single eye

At first, the cloudiness in your vision caused by a cataract may affect only a small part of the eye lens and you may be unaware of any vision loss. As the cataract grows larger, it clouds more of your lens and distorts the light passing through the lens. This may lead to signs and symptoms you are more likely to notice.
Tests and diagnosis

To determine whether you have a cataract, your doctor will review your medical history and symptoms, and perform an eye examination. Your doctor may conduct several tests, including:

Asking you to read an eye chart (visual acuity test). A visual acuity test uses an eye chart to measure how well you can read a series of letters. Your eyes are tested one at a time, while the other eye is covered.

Using a chart or a viewing device with progressively smaller letters, your eye doctor determines if you have 20/20 vision or if your vision shows signs of impairment.

Using a light and magnification to examine your eye (slit-lamp examination). A slit lamp allows your eye doctor to see the structures at the front of your eye under magnification.
The microscope is called a slit lamp because it uses an intense line of light, a slit, to illuminate your cornea, iris, lens, and the space between your iris and cornea. The slit allows your doctor to view these structures in small sections, which makes it easier to detect any tiny abnormalities.

Dilating your eyes (retinal examination). To prepare for a retinal examination, your eye doctor puts dilating drops in your eyes to open your pupils wide. This makes it easier to examine the back of your eyes (retina).

Using a slit lamp or a special device called an ophthalmoscope, your eye doctor can examine your lens for signs of a cataract.

Western Medicine Treatments and drugs

The only effective treatment for cataracts is surgery.

When to consider cataract surgery

Talk with your eye doctor about whether surgery is right for you. Most eye doctors suggest considering cataract surgery when your cataracts begin to affect your quality of life or interfere with your ability to perform normal daily activities, such as reading or driving at night.

It is up to you and your doctor to decide when cataract surgery is right for you. For most people, there is no rush to remove cataracts because they usually don't harm the eye.

Delaying the procedure won't make it more likely that you won't recover your vision if you later decide to have cataract surgery. Take time to consider the benefits and risks of cataract surgery with your doctor.

If you choose not to undergo cataract surgery now, your eye doctor may recommend periodic follow-up exams to see if your cataracts are progressing. How often you'll see your eye doctor depends on your situation.

What happens during cataract surgery

Cataract surgery involves removing the clouded lens and replacing it with a clear artificial lens. The artificial lens, called an intraocular lens, is positioned in the same place as your natural lens, and it remains a permanent part of your eye.

For some people, other eye problems prohibit the use of an artificial lens. In these situations, once the cataract is removed, vision may be corrected with eyeglasses or contact lenses.

Cataract surgery is generally done on an outpatient basis, which means you won't need to stay in a hospital after the surgery.
During cataract surgery, your eye doctor uses local anesthesia to numb the area around your eye, but you usually stay awake during the procedure.

Cataract surgery is generally safe, but it carries a risk of infection and bleeding. Cataract surgery increases the risk of retinal detachment.

After the procedure, you will have some discomfort for a few days. You generally will be healed within eight weeks.

If you need cataract surgery in both eyes, your doctor will schedule surgery to remove the cataract in the second eye a month or two after the first surgery.