What is a cataract?
A cataract occurs when the lens of the eye clouds over, affecting vision in one or both eyes. Cataracts are a common problem of aging and more than half of all Americans will have a cataract by age 80. Cataracts can also occur in younger people, in their 40s or 50s, however, most cataracts that occur at this age are small and have little to no effect on a person's vision. It's not until a person is in his or her 60s that cataracts start to affect sight. More than 22 million Americans have cataracts.
What causes cataracts?
The lens of the eye helps us focus and see things clearly. It is made up of mostly water and protein. As we age, this protein may clump together and cloud the lens, forming a cataract. The cataract may grow over time, making vision more difficult.
The aging process is the most common cause of this protein buildup that leads to cataracts. Other causes of cataracts include diabetes, trauma to the eye, smoking, certain medications (corticosteroids and phenothiazines), high alcohol intake, unprotected ultraviolet (UV) exposure, nutritional deficiency, and eye surgery. In rare cases, cataracts may be present at birth or shortly thereafter.
What are the symptoms of a cataract?
The main symptom of cataracts is cloudy or blurry vision. Cataracts do not cause pain. Initially, cataracts may only cause a small part of the lens to be cloudy which may not affect your vision. Cataracts glow gradually over time, so it can take a while to notice vision changes. As the cataracts increase in size, vision may become duller or blurrier.
Common symptoms of cataracts include: - Cloudy, hazy, dim, or blurry vision
- Colors appear faded, or less intense
- Sensitivity to glare from lights, particularly at night
- Seeing halos around lights
- Decreased night vision or difficulty seeing in dim light
- Greater need for reading light
- Double vision
- Frequent prescription changes for eyeglasses or contact lenses
There are multiple types of cataracts.
Most cataracts develop as a result of the aging process and are considered primary cataracts. Other types of cataracts include:
- Secondary cataract – Development is related to a secondary cause, such as surgery, other eye problems (for example, glaucoma), diabetes, or steroid use
- Traumatic cataract – These develop after an injury to the eye
- Congenital cataract – These are present at birth or appear shortly thereafter
- Radiation cataract – Develops after exposure to some types of radiation
Cataracts can be classified by how they develop, as well as their location.
- Nuclear cataract – located in the center of the lens
- Cortical cataract – affects the layer of the lens surrounding the nucleus
- Posterior capsular cataract – located in the back outer layer of the lens
Prolonged exposure to sunlight is a risk factor for cataracts.
Prolonged exposure to the ultraviolet (UV) rays of sunlight is a risk factor for cataracts. Long-term exposure to this type of radiation can cause changes in the lens that can lead to development of cataracts. The good news is that wearing sunglasses regularly can help protect your eyes from the damage of UV rays and may help prevent cataracts from developing or getting worse.
Surgery is the only treatment to cure cataracts.
There are several ways to manage cataract symptoms in the early stages, however; if a cataract starts to interfere with vision significantly, surgery is the only way to cure it.
In the early stages, when there are few symptoms, cataracts can often be managed with new prescriptions for eyeglasses or contact lenses, using brighter lighting, wearing anti-glare sunglasses, and using magnifying lenses. Cataracts develop slowly and gradually, so even if you are diagnosed with one, it may be years before surgery is needed, if ever.
Once cataracts reach a stage where they interfere with daily activities such as driving or reading, surgery may be recommended. In cataract surgery, the cloudy lens is removed and replaced with an artificial lens. Cataract removal is a common and safe procedure, and about 90% of people who have it report better vision afterwards.
In some cases cataracts are removed even when they do not cause vision problems, such as when a patient also has age-related macular degeneration or diabetic retinopathy.
Cataracts can lead to blindness.
If not treated, cataracts can lead to blindness. Cataract-related blindness is less prevalent in developed countries, but the World Health Organization estimates 51% of world blindness is due to cataracts, making it the leading cause of blindness worldwide.
Cataracts cannot be prevented.
There is no way to prevent age-related cataracts from developing. However, there steps you can take to help delay or prevent the development of other types of cataracts.
- Diabetics should manage blood sugar levels
- Protect eyes with sunglasses when in sunlight
- Quit smoking
- Eat plenty of fruits and vegetables for antioxidants
- Limit alcohol consumption
- Have your eyes examined regularly to spot problems in early stages
Images provided by:
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National Eye Institute. Cataracts Defined.
American Optometric Association. Cataracts.
University of Maryland Medical Center. Cataracts.
World Health Organization. Visual Impairment and Blindness.
Johns Hopkins Medicine. Wilmer Eye Institute. Cataracts FAQ.
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