A cataract develops when the lens in your eye becomes cloudy. The lens is part of your eye that helps focus images. Cataracts can cause problems such as blurry or dulled vision, sensitivity to light and glare, and seeing shadows or ghost–like images.

Cataracts always get worse. Surgery is the only way to remove it. It is your choice when to have cataract surgery. Most people wait until their vision problems interfere with daily life. You can also decide not to have your cataract removed.

During cataract surgery, your eye surgeon will remove the cloudy lens. He will replace it with an IOL—intraocular lens, a clear plastic artificial lens. The most common is a monofocal (one focus) IOL. This helps improve vision at mostly just one distance, either near or far. You will probably need glasses to see clearly at other distances.

Cataract surgery only corrects vision problems caused by cataracts. This surgery cannot correct vision problems caused by glaucoma, diabetes, age-related macular degeneration, or other eye illnesses or injuries.

Many patients with cataracts also have astigmatism or presbyopia (eye problems that make it hard to see).

Astigmatism causes blurry vision. Normally, the clear window of the eye, the cornea, is round like a ball. If an eye has astigmatism, the cornea is more football–shaped. This blurs the focus.

Presbyopia makes it hard for the eye to focus at near. Most people get this as they age. People at any age who have cataract surgery with a monofocal IOL focused for distance vision will have some presbyopia. People with presbyopia might hold a book or menu at arm’s length to try to see it more clearly.

Glasses help astigmatism and presbyopia. If you want to wear glasses less often, the eye surgeon can put in a special IOL or do an extra procedure during cataract surgery to treat these eye problems.

You have to pay extra for special IOLs or extra surgical procedures. Medicare and private insurance do not pay for these. Your eye surgeon will let you know if you have astigmatism or presbyopia. Your eye surgeon will give you more information if you are interested in these treatments. You will be asked to sign another consent for them.

Risks from cataract surgery include vision loss, blindness, or not getting the result you want. You could also have bleeding, infection, a droopy eyelid, or glaucoma (high eye pressure). You could get a detached retina. This is when the retina, at the back of the eye, pulls away from where it is attached. You may need surgery to fix the detached retina. Your eye may be injured by surgery or anesthesia. You may need another surgery later to take out pieces of the cataract that were not removed during the cataract surgery.

Risks from an IOL. The IOL may be too weak or too strong. The eye surgeon might not be able to insert the IOL of your choice. The eye surgeon may need to replace or reposition your IOL months or years after surgery.

Problems during surgery that need immediate treatment. Your surgeon may need to do more surgery right away or change your surgery to treat this new problem.

Anesthesia can cause heart and breathing problems. Very rarely, it can cause death. Anesthesia can also injure your eye and cause vision loss or double vision.

Other risks. There is no guarantee that cataract surgery will improve your vision. It is possible that cataract surgery or anesthesia may make your vision worse, cause blindness, or even the loss of an eye. These problems can appear weeks, months, or even years after surgery.

You may need to wear glasses after cataract surgery.