What is a cataract?
A cataract is an eye disease in which the clear lens of the eye becomes cloudy or opaque, causing a decrease in vision.
The lens is a portion of the eye that is normally clear. It focuses rays of light entering the eye onto the retina, the light-sensitive tissue at the back of the eye. In order to get a clear image onto the retina, the portions of the eye in front of the retina, including the lens, must be clear and transparent. The light initiates a chemical reaction within the retina. The chemical reaction, in turn, initiates an electrical response which is carried to the brain through the optic nerve. The brain then interprets what the eye sees.
In a normal eye, light passes through the transparent lens to the retina. The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image striking the retina will be blurry and the vision will be blurry. The extent of the visual disturbance is dependent upon the degree of cloudiness of the lens.
Most cataracts are related to aging. Cataracts are very common in older people. A cataract can occur in either or both eyes. Individuals with a cataract in one eye usually go on to develop a cataract in the other eye as well. A cataract is not contagious and cannot spread from one eye to the other or from person to person. Cataracts do not cause the eye to tear abnormally. They are neither painful nor make the eye itchy or red.
Although vision can be restored in most people with cataracts, age-related cataracts are still the most common cause of blindness in the world, primarily because many third-world nations lack appropriate surgical services.
As life span increases in the developed world due to modern technology and new methods of treatment of acute and chronic disease, the incidence of age-related cataracts will continue to increase.
Symptoms of Cataracts
Cataracts are more common in older people and the symptoms usually develop over time. In fact, most people do not realize they have cataracts at first because the symptoms develop so slowly.
Some symptoms of cataracts include:
Â· Double vision in one eye
â€¢ Blurry, cloudy, or dimming vision (increasing over time)
â€¢ Sensitivity to lights, such as the sun or headlights on other cars
â€¢ Color dullness
â€¢ A “halo” appearance around lights (especially at night)
â€¢ Regular changes in eye sight levels, causing a change in glasses prescription
Symptoms of cataracts vary from person to person, although most patients report that they feel as though they are constantly looking through a foggy or dirty window. This experience will worsen as the eye condition develops over time.
If you are experiencing these symptoms, your doctor will need to make changes to your glasses prescriptions. In severe cases, surgery may be needed to correct the problem.
Are there other types of cataract?
Yes. Although most cataracts are related to aging, there are other types of cataract:
Secondary cataract. Cataracts can form after surgery for other eye problems, such as glaucoma. Cataracts also can develop in people who have other health problems, such as diabetes. Cataracts are sometimes linked to steroid use.
Traumatic cataract. Cataracts can develop after an eye injury, sometimes years later.
Congenital cataract. Some babies are born with cataracts or develop them in childhood, often in both eyes. These cataracts may be so small that they do not affect vision. If they do, the lenses may need to be removed.
Radiation cataract. Cataracts can develop after exposure to some types of radiation.
What Causes Cataracts?
No one knows for sure why the eye’s lens changes as we age, forming cataracts. But researchers worldwide have identified factors that may cause cataracts or are associated with cataract development. Besides advancing age, cataract risk factors include:
Â· Ultraviolet radiation from sunlight and other sources
Â· Prolonged use of corticosteroid medications
Â· Statin medicines used to reduce cholesterol
Â· Previous eye injury or inflammation
Â· Previous eye surgery
Â· Hormone replacement therapy
Â· alcohol consumption
Â· High myopia
Â· Family history
One theory of cataract formation that’s gaining favor is that many cataracts are caused by oxidative changes in the human lens. This is supported by nutrition studies that show fruits and vegetables high in antioxidants may help prevent certain types of cataracts.
What can I do to protect my vision?
Wearing sunglasses and a hat with a brim to block ultraviolet sunlight may help to delay cataract. If you smoke, stop. Researchers also believe good nutrition can help reduce the risk of age-related cataract. They recommend eating green leafy vegetables, fruit, and other foods with antioxidants.
If you are age 60 or older, you should have a comprehensive dilated eye exam at least once every two years. In addition to cataract, your eye care professional can check for signs of age-related macular degeneration, glaucoma, and other vision disorders. Early treatment for many eye diseases may save your sight.