Cataract Surgery

A cataract is a painless, cloudy area in the lens of the eye. The lens is enclosed in a lining called the lens capsule. Cataract surgery separates the cataract from the lens capsule. In most cases, the lens will be replaced with an intraocular lens implant (IOL). If an IOL cannot be used, contact lenses or eyeglasses…

Cataract Surgery

Surgery Overview

A cataract is a painless, cloudy area in the lens of the eye. The lens is enclosed in a lining called the lens capsule. Cataract surgery separates the cataract from the lens capsule. In most cases, the lens will be replaced with an intraocular lens implant (IOL). If an IOL cannot be used, contact lenses or eyeglasses must be worn to compensate for the lack of a natural lens.

Phacoemulsification and standard extracapsular cataract extraction (ECCE) are surgical methods that remove the cataract as well as the front portion of the lens capsule (anterior capsule). The back of the lens capsule (posterior capsule) is left inside the eye to keep the vitreous gel in the back of the eye from oozing forward through the pupil and causing problems. The posterior capsule also supports the IOL and helps keep it in the proper position. These types of surgery are usually done in an outpatient setting and not in a hospital.

Phacoemulsification (small-incision surgery) is the most common type of cataract surgery. It is used more often than standard ECCE, even though they are similar procedures.

During phacoemulsification surgery:

  • Two small incisions are made in the eye where the clear front covering (cornea) meets the white of the eye (sclera).
  • A circular opening is created on the lens surface (capsule).
  • A small surgical instrument (phaco probe) is inserted into the eye.
  • Sound waves (ultrasound) are used to break the cataract into small pieces. Sometimes a laser is used too. The cataract and lens pieces are removed from the eye using suction.
  • An intraocular lens implant (IOL) may then be placed inside the lens capsule.
  • Usually, the incisions seal themselves without stitches.

During standard ECCE:

  • An 8 mm to 10 mm incision is made in the eye where the clear front covering of the eye (cornea) meets the white of the eye (sclera).
  • Another small incision is made into the front portion of the lens capsule. The lens is removed, along with any remaining lens material.
  • An IOL may then be placed inside the lens capsule. And the incision is closed.

Children and infants

In some children, surgery to remove a cataract that causes a lot of vision loss may be very important in preventing blindness. The most critical period for the development of sight is from birth to 3 months. The earlier cataracts in children are diagnosed and treated, the more likely it is that their eyesight will be protected.


Most cataract surgery is done using a topical anesthetic (eyedrops) or a local anesthetic. Local anesthetic may involve a sedative for relaxation followed by an injection beside, under, or inside the eye to deaden nerves and prevent blinking or eye movement during surgery.

General anesthetic may be needed for:

  • People with extreme anxiety that cannot be controlled with simple sedation or counseling.
  • People who are unable to follow instructions during surgery.
  • People who are allergic to certain local anesthetics.
  • People with other medical conditions that require the use of a general anesthetic.
  • Children.

What To Expect

Before you leave the outpatient center, you will get the immediate eye care that you need after surgery. The surgeon will review the symptoms of possible complications, eye protection, activities, medicines, and required visits (see below). He or she will also tell you what to do for emergency care if you need it. Portions of the follow-up may be done by another health professional, such as an optometrist or a community health nurse.

The eye that was operated on may be bandaged for 1 night after surgery. You will wear a protective shield over the eye at night for about a week. There is normally no significant pain after surgery.

You most likely will need to see the doctor for checkups 1 or 2 days after surgery, and again within a few weeks after surgery. If any complications occur, visits should be sooner and more frequent.

Checkups following cataract surgery include:

  • Ophthalmoscopy, to evaluate the inside of the eye.
  • Measurement of visual acuity and eye pressure (tonometry).
  • A slit lamp exam, to check for lens clarity.

Most people get a new eyeglass prescription about 6 weeks after surgery.

Contact your doctor promptly if you notice any signs of complications following cataract surgery, such as:

  • Decreasing vision.
  • Increasing pain.
  • Increasing redness.
  • Swelling around the eye.
  • Discharge from the eye.
  • New floaters, flashes of light, or changes in your field of vision.

Why It Is Done

The decision to have this procedure is based on whether:

  • Your work or lifestyle is affected by vision problems caused by the cataract.
  • Glare caused by bright lights is a problem.
  • You cannot pass a vision test required for a driver’s license.
  • You have double vision.
  • You notice a big difference in vision when you compare one eye to the other.
  • You have another vision-threatening eye disease, such as diabetic retinopathy or macular degeneration.

The surgeon may need to do standard extracapsular cataract extraction (ECCE) instead of phacoemulsification if the cataract is too hard to be broken up by sound waves (ultrasound).

How Well It Works

Cataract surgery is successful for 85 to 92 out of 100 adults. Surgery may also improve vision in infants who have cataracts.

In one large study, 95 out of 100 adults were satisfied with the results of their surgery. The people who were not satisfied were older adults who had other eye problems along with cataracts.footnote 1

People who have surgery for cataracts usually have:

  • Improved vision.
  • Increased mobility and independence.
  • Relief from the fear of going blind.

Studies done with adults 1 year after surgery show that phacoemulsification works better than standard extracapsular cataract extraction (ECCE) to improve vision.footnote 2 Also, recovery of sight occurs sooner after surgery with phacoemulsification. And it is less likely that you will need glasses for distance vision after phacoemulsification surgery.


Fewer than 10 out of 100 people have complications from cataract surgery that could threaten their sight or require further surgery.footnote 3 The rate of complications increases in people who have other eye diseases in addition to the cataract.

Although the risk is low, surgery for cataracts does involve the risk of partial to total vision loss if the surgery is not successful or if there are complications. Some complications can be treated and vision loss reversed, but others cannot. Complications that may occur with cataract surgery include:

  • Infection in the eye (endophthalmitis).
  • Swelling and fluid in the center of the nerve layer (cystoid macular edema).
  • Swelling of the clear covering of the eye (corneal edema).
  • Bleeding in the front of the eye (hyphema).
  • Detachment of the nerve layer at the back of the eye (retinal detachment).

Complications that may occur some time after surgery include:

  • Problems with glare.
  • Dislocated intraocular lens.
  • Clouding of the portion of the lens covering (capsule) that remains after surgery, often called aftercataract (posterior capsular opacification). This is usually not a big problem and can be treated with laser surgery, if needed. The type of IOL may affect how likely it is to have clouding after surgery.
  • Retinal detachment.
  • Glaucoma.
  • Astigmatism or strabismus.
  • Sagging of the upper eyelid (ptosis).

What To Think About

Before you have surgery for cataracts, tell your doctor all of the medicines you are taking. That way, your doctor can be prepared to handle any problems that arise. For example, alpha-blockers (such as tamsulosin or terazosin) and blood thinners can cause problems during the surgery.

Removing cataracts using phacoemulsification is preferred over standard extracapsular surgery because:

  • The surgery can be done more quickly.
  • There is less astigmatism after surgery.
  • Recovery of sight after surgery is faster.
  • The risk of complications after surgery is less.

The improvement of vision is the same for both procedures. But the healing process is quicker for phacoemulsification.

The more experience your surgeon has, the less likely you are to have problems. Ask your family doctor or optometrist to suggest a surgeon.

People usually need glasses after cataract surgery, no matter which type of surgery is done. But the need for glasses and the type of glasses you need will depend on the type of intraocular lens implant, or IOL, that you choose. Talk to your doctor about the pros and cons of each type of IOL.

If you have an astigmatism, your surgery may cost more. Talk to your doctor about your treatment options and costs.



  1. American Academy of Ophthalmology (2011). Cataract in the Adult Eye (Preferred Practice Pattern). San Francisco: American Academy of Ophthalmology. Available online:
  2. Allen D (2011). Cataract, search date May 2010. Online version of BMJ Clinical Evidence. Also available online:
  3. Harper RA, Shock JP (2011). Lens. In P Riordan-Eva, JP Whitcher, eds., Vaughan and Asbury’s General Ophthalmology, 18th ed., pp. 174–182. New York: McGraw-Hill.


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