A cataract is a clouding of the normally clear lens of the 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.
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.
Some inherited genetic disorders that cause other health problems can increase your risk of cataracts. Cataracts can also be caused by other eye conditions, past eye surgery or medical conditions such as diabetes. Long-term use of steroid medications, too, can cause cataracts to develop.
Cataracts affecting the center of the lens (nuclear cataracts). A nuclear cataract may at first cause more nearsightedness or even a temporary improvement in your reading vision. But with time, the lens gradually turns more densely yellow and further clouds your vision.
Cataracts you're born with (congenital cataracts). Some people are born with cataracts or develop them during childhood. These cataracts may be genetic, or associated with an intrauterine infection or trauma.
These cataracts may also be due to certain conditions, such as myotonic dystrophy, galactosemia, neurofibromatosis type 2 or rubella. Congenital cataracts don't always affect vision, but if they do, they're usually removed soon after detection.
Studies haven't proved that antioxidants in pill form can prevent cataracts. But a large population study recently showed that a healthy diet rich in vitamins and minerals was associated with a reduced risk of developing cataracts. Fruits and vegetables have many proven health benefits and are a safe way to increase the amount of minerals and vitamins in your diet.
A cataract is a cloudy area in the lens of your eye (the clear part of the eye that helps to focus light). Cataracts are very common as you get older. In fact, more than half of all Americans age 80 or older either have cataracts or have had surgery to get rid of cataracts.
Surgery. Your doctor might suggest surgery if your cataracts start getting in the way of everyday activities like reading, driving, or watching TV. During cataract surgery, the doctor removes the clouded lens and replaces it with a new, artificial lens (also called an intraocular lens, or IOL). This surgery is very safe, and 9 out of 10 people who get it can see better afterwards.
If you have cataract symptoms, see an eye doctor (ophthalmologist) for a complete exam. The doctor will need to dilate your pupil to see inside your eye. During this test, special eye drops widen your pupil (the black part of the eye). When the pupil is wide open, your doctor checks the health of your eye. Your doctor can see if you have cataracts or other problems and find out how much of your vision is blocked.
Phacoemulsification is the most common procedure for cataracts. Your ophthalmologist makes a small opening in the eye to reach the clouded lens. Using high-frequency sound waves (ultrasound) or a laser, your ophthalmologist breaks the lens into pieces. Then the doctor suctions lens fragments from your eye and puts in a new plastic lens.
Cataracts usually develop slowly. New glasses, brighter lighting, anti-glare sunglasses or magnifying lenses can help at first. Surgery is also an option. It involves removing the cloudy lens and replacing it with an artificial lens. Wearing sunglasses and a hat with a brim to block ultraviolet sunlight may help to delay cataracts.
In its early stages, a cataract may not cause a problem. The cloudiness may affect only a small part of the lens. However, the cataract may grow larger over time and affect more of the lens. This can make it harder for you to see. If less light reaches the retina, it becomes even harder to see. Your vision may become dull and blurry. Cataracts cannot spread from one eye to another. Many people do, however, get cataracts in both eyes.
Congenital cataracts. Some babies are born with cataracts. Some children develop them in childhood, often in both eyes. Some congenital cataracts do not affect eyesight, but others do and need to be removed.
Often in the disease's early stages, you may not notice any changes in your vision. Since cataracts tend to grow slowly, your eyesight will get worse slowly. Certain cataracts can also cause your close-up vision to get better for a short time. But your eyesight is likely to get worse as the cataract grows. The symptoms of cataracts may look like other eye conditions. Talk with a healthcare provider for a diagnosis.
Cataract surgery is one of the most common surgeries. It is also one of the safest and most effective. Surgery involves swapping out the cloudy lens with a new lens. If you have cataracts in both eyes, they are usually not taken out at the same time. Your eye healthcare provider will need to do the surgery on each eye separately.
Over time, cataracts will harm your vision. Cataract surgery can bring back your vision. However, a possible complication of cataract surgery is an "after-cataract." An "after-cataract" happens when part of the natural lens that is purposely not taken out during cataract surgery becomes cloudy and blurs your eyesight. Unlike a cataract, an "after-cataract" can be treated with a method called YAG laser capsulotomy. The healthcare provider uses a laser beam to make a tiny hole in the cloudy membrane behind the lens to let the light pass through. After-cataracts may develop months, or even years, after cataract surgery.
A cataract is a cloudy area in the lens of the eye that leads to a decrease in vision. Cataracts often develop slowly and can affect one or both eyes. Symptoms may include faded colors, blurry or double vision, halos around light, trouble with bright lights, and trouble seeing at night. This may result in trouble driving, reading, or recognizing faces. Poor vision caused by cataracts may also result in an increased risk of falling and depression. Cataracts cause 51% of all cases of blindness and 33% of visual impairment worldwide.
Prevention includes wearing sunglasses and a wide brimmed hat, eating leafy vegetables and fruits,[clarification needed] and avoiding smoking. Early on the symptoms may be improved with glasses. If this does not help, surgery to remove the cloudy lens and replace it with an artificial lens is the only effective treatment. Cataract surgery is not readily available in many countries, and surgery is needed only if the cataracts are causing problems and generally results in an improved quality of life.
About 20 million people worldwide are blind due to cataracts. It is the cause of approximately 5% of blindness in the United States and nearly 60% of blindness in parts of Africa and South America. Blindness from cataracts occurs in about 10 to 40 per 100,000 children in the developing world, and 1 to 4 per 100,000 children in the developed world. Cataracts become more common with age. In the United States, cataracts occur in 68% of those over the age of 80 years. Additionally they are more common in women, and less common in Hispanic and Black people.
Signs and symptoms vary depending on the type of cataract, though considerable overlap occurs. People with nuclear sclerotic or brunescent cataracts often notice a reduction of vision. Nuclear cataracts typically cause greater impairment of distance vision than of near vision. Those with posterior subcapsular cataracts usually complain of glare as their major symptom.
Age is the most common cause of cataracts. Lens proteins denature and degrade over time, and this process is accelerated by diseases such as diabetes mellitus and hypertension. Environmental factors, including toxins, radiation, and ultraviolet light have cumulative effects which are worsened by the loss of protective and restorative mechanisms due to alterations in gene expression and chemical processes within the eye.
Oxidative stress is an important pathogenic mechanism in cataract formation (see for review). Senile cataracts are associated with a decrease in antioxidant capacity in the lens. An increase in oxidative stress in the lens or a decrease in the ability to remove reactive oxygen species can lead to the lens becoming more opaque.
Blunt trauma causes swelling, thickening, and whitening of the lens fibers. While the swelling normally resolves with time, the white color may remain. In severe blunt trauma, or in injuries that penetrate the eye, the capsule in which the lens sits can be damaged. This damage allows fluid from other parts of the eye to rapidly enter the lens leading to swelling and then whitening, obstructing light from reaching the retina at the back of the eye. Cataracts may develop in 0.7 to 8.0% of cases following electrical injuries. Blunt trauma can also result in star- (stellate) or petal-shaped cataracts.
Cataracts can arise as an effect of exposure to various types of radiation. X-rays, one form of ionizing radiation, may damage the DNA of lens cells. Ultraviolet light, specifically UVB, has also been shown to cause cataracts, and some evidence indicates sunglasses worn at an early age can slow its development in later life. Microwaves, a type of nonionizing radiation, may cause harm by denaturing protective enzymes (e.g., glutathione peroxidase), by oxidizing protein thiol groups (causing protein aggregation), or by damaging lens cells via thermoelastic expansion. The protein coagulation caused by electric and heat injuries whitens the lens. This same process is what makes the clear albumen of an egg become white and opaque during cooking. 2b1af7f3a8