Cataract

What is a cataract?

A cataract is a clouding of the lens in the eye. This clouding affects vision. A cataract can happen in one or both eyes, but does not spread from one eye to the other. Most cataracts happen as the result of aging, and they are very common in older people. More than half of all Americans will have had a cataract at one time or another by the time they are 80 years old.

How do cataracts affect vision?

Cataracts affect vision by creating a cloudy area on the lens of the eye. This cloudy area can get larger over time and cause serious vision problems. The lens helps to focus light on the retina, the light-sensitive tissue at the back of the eye. In a normal eye, light passes through a clear lens to the retina, which turns it into nerve signals that are passed 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 that the brain receives will be blurred. Age-related cataracts can also cause discoloration of the lens. Over time, the clear lens slowly changes to a yellowish or brownish color, which tints vision. This gradual change in tint does not make vision blurry.

Are there different types of cataracts?

Yes. Although most cataracts are related to aging, there are other types of cataracts. They include:

  • Traumatic cataract – These are cataracts that develop after an injury to the eye. In some cases, cataracts might not develop until years after the injury.
  • Congenital cataract – These are cataracts that develop in childhood or that some babies are born with. Often, this type of cataract affects both eyes. In some cases, these cataracts are so small that they do not affect vision. If they do affect vision, an eye doctor will remove the lenses from the eyes.
  • Radiation cataract – These are cataracts that can develop after exposure to some types of radiation.

What causes cataracts?

A cataract happens when protein in the lens of the eye clumps together and forms a cloud. The lens is made of mostly water and protein. In normal eyes, the protein is arranged in a precise way that keeps the lens clear, allowing light to pass through it. But as we age, some of the protein can clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract might grow larger and cloud more of the lens, making it harder for the person to see. Scientists are not sure why cataracts happen. It might be that the protein in the lens changes from wear and tear over many years. Health problems such as smoking and diabetes might make cataracts more likely.

What are the risk factors for cataracts?

Risk factors include:

  • Age – The risk of cataract increases with age, but a person does not have to be elderly to have an age-related cataract. People can have age-related cataracts in their 40s and 50s. But during middle age, most cataracts are small and do not affect vision. After age 60, it becomes more common for cataracts to harm vision.
  • Certain diseases, such as diabetes
  • Lifestyle choices, such as smoking and alcohol use
  • Environmental factors, such as prolonged exposure to sunlight

What can I do to reduce my risk of cataracts?

There are a few things you can do to reduce your risk. You can:

  • Protect your eyes from ultraviolet light – Wear sunglasses and a hat to block sunlight. This can help delay cataracts.
  • Quit smoking, if you smoke.
  • Eat a healthy diet – Science suggests good nutrition can help reduce the risk of age-related cataracts. Choose a diet with green leafy vegetables, fruit, and other foods rich in antioxidants.

If you are age 60 or older, you should also have a comprehensive dilated eye exam at least once every one to two years. In addition to checking for cataracts, your eye doctor can check for signs of age-related macular degeneration, glaucoma, and other vision disorders. For many eye diseases, early treatment can save vision.

What are the symptoms of a cataract?

The most common symptoms of a cataract are:

  • Cloudy or blurry vision.
  • Colors appear faded
  • Glare - Headlights, lamps, or sunlight might appear too bright. Lights might appear with a halo around them.
  • Problems with night vision
  • Double vision or seeing multiple images in one eye - This symptom might go away as the cataract gets larger.
  • Frequent changes eyeglasses or contacts prescription – A person with cataracts might need a new prescription as often as every few months.

These symptoms can also be a sign of other eye problems. If you have any of these symptoms, tell your eye doctor.

How is a cataract detected?

Cataract is detected during a comprehensive eye exam. This exam might include:

  • Visual acuity test – This test uses an eye chart to measure how well you see at various distances.
  • Dilated eye exam – For this test, the eye doctor puts drops in your eyes to widen, or dilate, the pupils. He or she will then use 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 might remain blurred for several hours.
  • Tonometry – This test involves an instrument that measures the pressure inside the eye. Your doctor will apply numbing drops to your eye for this test.

How is a cataract treated?

The damage from cataracts cannot be undone, but there are many ways to address the symptoms, including:

  • New eyeglasses prescriptions
  • Brighter lights
  • Anti-glare sunglasses
  • Magnifying lenses

If these options do not help, your doctor might recommend surgery. Surgery for cataracts involves removing the cloudy lens and replacing it with an artificial, or intraocular, lens. Depending on your individual situation, you might not need surgery for cataracts. Your eye doctor can explain the benefits and risks of surgery and help you make the decision that is right for you. For some people, delaying cataract surgery does not cause long-term damage to the eye or problems with surgery later on. Some people need surgery for cataracts so that their eye doctor can monitor the back of their eye for other conditions. Many people who need cataract surgery have other eye problems, such as age-related macular degeneration, glaucoma, or diabetic retinopathy. For these people, cataracts can prevent the eye doctor from effectively examining and treating other eye conditions. If you decide to have surgery, your eye doctor might refer you to a specialist to perform the surgery. If you have cataracts in both eyes that require surgery, the surgery will be performed on each eye at separate times, typically four to eight weeks apart.

What are the different types of cataract surgery?

There are two types of cataract surgery. Your doctor can explain the differences and help decide which one is best for you. They include:

  • Phacoemulsification (or "phaco") – For this surgery, the doctor makes a small incision on the side of the cornea. The cornea is the clear, dome-shaped surface that covers the front of the eye. The doctor then inserts a tiny probe into the eye. This device gives off ultrasound waves that soften and break up the lens so that it can be removed with suction. Most cataract surgery today is done with phacoemulsification. It is also called "small incision cataract surgery."
  • Extracapsular cataract extraction (ECCE) surgery – For this surgery, the doctor makes a larger 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 with suction. This surgery is usually only used for cataracts that cannot be treated with phacoemulsification, such as very dense or mature cataracts.

After the original lens has been removed, it is usually replaced with 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 the eye. The IOL improves vision by clearly focusing light onto the retina. You will not feel or see the new lens in your eye. Some people have another eye disease or problems during surgery that prevent them from getting an IOL. For these people, the doctor might recommend a soft contact lens or glasses that provide high magnification.

What are the risks of cataract surgery?

As with any surgery, cataract surgery poses risks, such as infection and bleeding. Before cataract surgery, your doctor might ask you to temporarily stop taking certain medications that increase your risk of bleeding during surgery. After surgery, you must keep your eye clean, wash your hands before touching your eye, and use the medications your eye doctor prescribes to help minimize the risk of infection. A serious infection can result in loss of vision. Having cataract surgery puts a person at a slightly higher risk of a condition called retinal tear or detachment. People who have other eye disorders, such as high myopia (nearsightedness), are at even higher risk of retinal detachment after cataract surgery. Ask your eye doctor about the risks you face from surgery. He or she can help you make the decision that is right for you.

Is cataract surgery effective?

Cataract removal is one of the safest and most effective types of surgery. It improves vision in about 90 percent of cases. It is also is one of the most common surgeries performed in the United States.

What should I expect before surgery?

A week or two before surgery, your doctor will do some tests. These tests might include measuring the curve of your cornea and the size and shape of your eye. This information helps your doctor choose the right type of IOL. You might be asked not to eat or drink anything 12 hours before your surgery.

What should I expect during surgery?

Before surgery, the doctor will put drops into your eye to dilate the pupil. Many people choose to stay awake during surgery. Others might need to be put to sleep for a short time. If you choose to stay awake, you will have an anesthetic to numb the nerves in and around your eye. This anesthetic will be given either with an injection near the eye or with topical anesthesia. Then, the doctor will perform the surgery. The surgery usually lasts less than one hour and is almost painless. After the operation, a patch and/or shield will be placed over your eye. Some people need to use eyedrops right after their surgery. Ask your eye doctor about when you should start using eyedrops. You will rest for a while. Your medical team will watch for any problems you might have, such as bleeding. Most people who have cataract surgery can go home the same day, but cannot drive themselves. You will need to arrange for a ride home.

What should I expect after surgery?

After surgery, it is normal to have itching and mild discomfort. It is also normal to have some fluid discharge. Your eye might be sensitive to light and touch. If you have discomfort, your doctor can suggest treatment. Moderate discomfort should go away on its own in one or two days. For a few days after surgery, your doctor might ask you to use eyedrops to help healing and lower the risk of infection. Ask your doctor about how to use your eyedrops, 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. As you continue to heal, 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.

Can problems develop after surgery?

Problems after surgery are rare, but they can happen. Problems can include:

  • Infection
  • Bleeding
  • Inflammation (pain, redness, swelling)
  • Loss of vision
  • Double vision
  • High or low eye pressure

With prompt medical attention, these problems can usually 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 or posterior capsular opacification (PCO). A PCO can develop months or years after cataract surgery. A PCO is treated with a procedure called a YAG laser capsulotomy. For this procedure, the doctor uses the laser to make a tiny hole in the eye tissue behind the lens to let light pass through. It is painless and rarely causes eye problems such as increased eye pressure. As a precaution, your doctor might give you eyedrops to lower your eye pressure before or after the procedure.

When will my vision be normal again?

You can return quickly to many everyday activities, but your vision might be blurry. The eye that is healing needs time to adjust and focus properly with the other eye, especially if the other eye has a cataract. Ask your doctor when you can start driving again. If you received an IOL, colors might appear very bright. This is because the IOL is clear, while your natural lens might have had a yellowish/brownish tint. Within a few months after receiving an IOL, you will become used to your improved color vision. When your eye heals, you might need new glasses or contact lenses.