A Cataract is a clouding of the eye's natural lens, which lies behind the iris and the pupil. The lens adjusts the eye's focus, letting us see things clearly both up close and far away. The lens is mostly made of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract, and over time, it may grow larger and cloud more of the lens, making it harder to see.
Looking through a cloudy lens is like trying to see through a frosty or fogged-up window. Clouded vision can make it more difficult to read, drive a car — especially at night — or see the expression on a friend's face. Cataracts commonly affect distance vision and cause problems with glare. They generally don't cause irritation or pain.
Hazy or blurred vision may indicate a cataract.
Cataract Symptoms and Signs
- Clouded, blurred or dim vision
- Increasing difficulty with vision at night
- Sensitivity to light and glare
- Halos around lights
- The need for brighter light
- and other activities
- Frequent changes in eyeglass or contact
- lens prescription
- Fading or yellowing of colors
- Double vision in a single eye
Cataracts are classified as one of three types:
1. A nuclear cataract forms in the nucleus and is due to natural aging changes.
2. A cortical cataract forms in the lens cortex, gradually extends its spokes from the outside of the lens to the center.
3. A subcapsular cataract begins at the back of the lens. People with diabetes, high farsightedness, retinitis pigmentosa or those taking high doses of steroids may develop this. The type of cataract you have will affect exactly which symptoms you experience and how soon they will occur.
What Causes Cataracts?
A cataract can develop in one or both of your eyes. However, in most cases — except for those caused by injury or trauma — cataracts tend to develop symmetrically in both eyes. A cataract may or may not affect the entire lens. Age-related changes in the lens aren't the only cause of cataracts. Some people are born with cataracts or develop them during childhood. There are many misconceptions about cataract. Cataract is not a film over the eye. A cataract does not spread from one eye to the other, nor is it a cause of irreversible blindness. How quickly the cataract develops varies among individuals and may even be different between the two eyes. Most age-related cataracts progress gradually over a period of years. Other cataracts, especially in younger people and people with diabetes, may progress rapidly over a short time.
Treatment
Cataracts can't be cured with medications, dietary supplements,exercise or optical devices. In the early stages of a cataract when symptoms are mild, a good understanding of the condition and a willingness to adjust your lifestyle can help. When symptoms begin to appear, you may be able to improve your vision for a while using new glasses, strong bifocals, magnification, appropriate lighting or other visual aids. Think about surgery when your cataracts have progressed enough to seriously impair your vision and affect your daily life.
Cataract surgery is very successful in restoring vision. In fact, it is the most frequently performed surgery in the United States, with more than 3 million Americans undergoing cataract surgery each year. During surgery, the surgeon will remove your clouded lens and in most cases replace it with a clear, plastic intraocular lens (IOL).
References:
- Program in Low Vision Therapy (2004). Page 7. Houston, TX: Region 4 EducationServiceCenter
What a cataract looks like
Created by Trish Duke
Region 4 Summer 2008