What is a cataract?
A cataract is a clouding of the lens in the eye that affects vision. The lens is a clear part of the eye that helps to focus light, or an image, on the retina. The retina is the light-sensitive tissue at the back of the eye. In a normal eye, light passes through the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent to the brain. The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image you see will be blurred.
Most cataracts are related to aging. Cataracts are very common in older people. By age 80, more than half of all Americans have either a cataract or have had cataract surgery. A cataract can occur in either or both eyes. It cannot spread from one eye to the other.
Age-related cataracts develop in two ways:
Clumps of protein reduce the sharpness of the image reaching the retina.
The lens consists mostly of water and protein. When the protein clumps up, it clouds the lens and reduces the light that reaches the retina. The clouding may become severe enough to cause blurred vision. Most age-related cataracts develop from protein clumping. When a cataract is small, the cloudiness affects only a small part of the lens. You may not notice any changes in your vision. Cataracts tend to “grow” slowly, so vision gets worse gradually. Over time, the cloudy area in the lens may get larger, and the cataract may increase in size. Seeing may become more difficult. Your vision may get duller or blurrier.
The clear lens slowly changes to a yellowish/brownish color, adding a brownish tint to vision.
As the clear lens slowly colors with age, your vision gradually may acquire a brownish shade. At first, the amount of tinting may be small and may not cause a vision problem. Over time, increased tinting may make it more difficult to read and perform other routine activities. This gradual change in the amount of tinting does not affect the sharpness of the image transmitted to the retina. If you have advanced lens discoloration, you may not be able to identify blues and purples. You may be wearing what you believe to be a pair of black socks, only to find out from friends that you are wearing purple socks.
The risk of cataract increases as you get older. Other risk factors for cataract include:
- Certain diseases (for example, diabetes)
- Personal behavior (smoking, alcohol use)
- The environment (prolonged exposure to ultraviolet sunlight)
What are the Symptoms of Cataracts?
- Cloudy or blurry vision.
- Colors seem faded.
- Glare. Headlights, lamps, or sunlight may appear too bright. A halo may appear around lights.
- Poor night vision.
- Double vision or multiple images in one eye. (This symptom may clear as the cataract gets larger.)
- Frequent prescription changes in your eyeglasses or contact lenses. These symptoms also can be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.
What is Cataract Surgery?
A cataract needs to be removed only when vision loss interferes with your everyday activities, such as driving, reading, or watching TV. You and your eye care professional can make this decision together. Once you understand the benefits and risks of surgery, you can make an informed decision about whether cataract surgery is right for you. In most cases, delaying cataract surgery will not cause long-term damage to your eye or make the surgery more difficult. You do not have to rush into surgery. Sometimes a cataract should be removed even if it does not cause problems with your vision. For example, a cataract should be removed if it prevents examination or treatment of another eye problem, such as age-related macular degeneration or diabetic retinopathy. If you choose surgery, your eye care professional may refer you to a specialist to remove the cataract. If you have cataracts in both eyes that require surgery, the surgery will be performed on each eye at separate times, usually four to eight weeks apart. Is cataract surgery effective? Cataract removal is one of the most common operations performed in the United States. It also is one of the safest and most effective types of surgery. In about 90 percent of cases, people who have cataract surgery have better vision afterward.
There are two types of cataract surgery. Your doctor can explain the differences and help determine which is better for you:
Phacoemulsification, or phaco. A small incision is made on the side of the cornea, the clear, dome-shaped surface that covers the front of the eye. Your doctor inserts a tiny probe into the eye. This device emits ultrasound waves that soften and break up the lens so that it can be removed by suction. Most cataract surgery today is done by phacoemulsification, also called “small incision cataract surgery.”
Extracapsular surgery; Your doctor makes a longer incision on the side of the cornea and removes the cloudy core of the lens in one piece. The rest of the lens is removed by suction.
A week or two before surgery, your doctor will do some tests. These tests may include measuring the curve of the cornea and the size and shape of your eye. This information helps your doctor choose the right type of IOL. You may be asked not eat or drink anything 8 hours before your surgery.
After the natural lens has been removed, it often is replaced by an artificial lens, called an intraocular lens (IOL). An IOL is a clear, plastic lens that requires no care and becomes a permanent part of your eye. Light is focused clearly by the IOL onto the retina, improving your vision. You will not feel or see the new lens. Some people cannot have an IOL. They may have another eye disease or have problems during surgery. For these patients, a soft contact lens, or glasses that provide high magnification, may be suggested.
What to Expect After Cataract Surgery
Itching and mild discomfort are normal after cataract surgery. Some fluid discharge is also common. Your eye may be sensitive to light and touch. If you have discomfort, your doctor can suggest treatment. After one or two days, moderate discomfort should disappear. For a few days after surgery, your doctor may ask you to use eye drops to help healing and decrease the risk of infection. Ask your doctor about how to use your eye drops, how often to use them, and what effects they can have. You will need to wear an eye shield or eyeglasses to help protect your eye. Avoid rubbing or pressing on your eye. When you are home, try not to bend from the waist to pick up objects on the floor. Do not lift any heavy objects. You can walk, climb stairs, and do light household chores. In most cases, healing will be complete within eight weeks. Your doctor will schedule exams to check on your progress.
Problems after surgery are rare, but they can occur. These problems can include infection, bleeding, inflammation (pain, redness, swelling), loss of vision, double vision, and high or low eye pressure. With prompt medical attention, these problems usually can be treated successfully. Sometimes the eye tissue that encloses the IOL becomes cloudy and may blur your vision. This condition is called an after-cataract. An after-cataract can develop months or years after cataract surgery. An after-cataract is treated with a laser. Your doctor uses a laser to make a tiny hole in the eye tissue behind the lens to let light pass through. This outpatient procedure is called a YAG laser capsulotomy. It is painless and rarely results in increased eye pressure or other eye problems. As a precaution, your doctor may give you eye drops to lower your eye pressure before or after the procedure.
You can return quickly to many everyday activities, but your vision may be blurry. The healing eye needs time to adjust so that it can focus properly with the other eye, especially if the other eye has a cataract. Ask your doctor when you can resume driving. If you received an IOL, you may notice that colors are very bright. The IOL is clear, unlike your natural lens that may have had a yellowish/brownish tint. Within a few months after receiving an IOL, you will become used to improved color vision. Also, when your eye heals, you may need new glasses or contact lenses.
Frequently asked questions about cataracts
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.
How is a cataract detected?
Cataract is detected through a comprehensive eye exam that includes:
1) Visual Acuity Test
This eye chart test measures how well you see at various distances. The norm has been set at 20/20. This means the “normal” person can see the 20/20 line of letters at 20 feet. When someone is 20/60, what they can see at 20 feet the “normal” person can see at a distance of 60 feet.
2) Dilated Eye Exam
Drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
3) Tonometry
An instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test. Your eye care professional also may do other tests to learn more about the structure and health of your eye.
Are there different types of cataract surgery?
There are two types of cataract surgery. Your doctor can explain the differences and help determine which is better for you:
1. Phacoemulsification, or phaco. A small incision is made on the side of the cornea, the clear, dome-shaped surface that covers the front of the eye. Your doctor inserts a tiny probe into the eye. This device emits ultrasound waves that soften and break up the lens so that it can be removed by suction. Most cataract surgery today is done by phacoemulsification, also called “small incision cataract surgery.”
2. Extracapsular surgery; Your doctor makes a longer incision on the side of the cornea and removes the cloudy core of the lens in one piece. The rest of the lens is removed by suction.
After the natural lens has been removed, it often is replaced by an artificial lens, called an intraocular lens (IOL). An IOL is a clear, plastic lens that requires no care and becomes a permanent part of your eye. Light is focused clearly by the IOL onto the retina, improving your vision. You will not feel or see the new lens. Some people cannot have an IOL. They may have another eye disease or have problems during surgery. For these patients, a soft contact lens, or glasses that provide high magnification, may be suggested.
What research is being done?
The National Eye Institute is conducting and supporting a number of studies focusing on factors associated with the development of age-related cataracts. These studies include:
· The effect of sunlight exposure, which may be associated with an increased risk of cataract.
· Vitamin supplements, which have shown varying results in delaying the progression of cataract.
· Genetic studies, which show promise for better understanding cataract development.
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.
What should I ask my eye care professional?
You can protect yourself against vision loss by working in partnership with your eye care professional. Ask questions and get the information you need to take care of yourself and your family.
What are some questions to ask about my eye disease or disorder?
· What is my diagnosis?
· What caused my condition?
· Can my condition be treated?
· How will this condition affect my vision now and in the future?
· Should I watch for any particular symptoms and notify you if they occur?
· Should I make any lifestyle changes?
About my treatment…
· What is the treatment for my condition?
· When will the treatment start and how long will it last?
· What are the benefits of this treatment and how successful is it?
· What are the risks and side effects associated with this treatment?
· Are there foods, drugs, or activities I should avoid while I’m on this treatment?
· If my treatment includes taking medicine, what should I do if I miss a dose?
· Are other treatments available?
About my tests…
· What kinds of tests will I have?
· What can I expect to find out from these tests?
· When will I know the results?
· Do I have to do anything special to prepare for any of the tests?
· Do these tests have any side effects or risks?
· Will I need more tests later?
Other suggestions
· If you don’t understand your eye care professional’s responses, ask questions until you do understand.
· Take notes or get a friend or family member to take notes for you. Or, bring a tape recorder to help you remember the discussion.
· Ask your eye care professional to write down his or her instructions to you.
· Ask your eye care professional for printed material about your condition.
· If you still have trouble understanding your eye care professional’s answers, ask where you can go for more information.
· Other members of your health care team, such as nurses and pharmacists, can be good sources of information. Talk to them, too. Today, patients take an active role in their health care. Be an active patient about your eye care.
