Cataract surgery

Also known as: Surgery for cataracts, Phacoemulsification, Standard extracapsular cataract extraction, ECCE

cataract is a painless, cloudy area in the lens of the eye. The lens is enclosed in a lining called the lens capsule. Aging and exposure to sunlight can cause cataracts. Cataracts can also happen after an eye injury, as a result of eye disease, after you use certain medicines, or as a result of health problems such as diabetes. Sometimes children are born with cataracts. These are called congenital cataracts.

What are the symptoms?

  • Cataracts can affect your vision.
  • You may have cloudy, fuzzy, or foggy vision.
  • You may see glare from lamps or the sun. You may have trouble driving at night because of glare from car headlights.
  • You may need frequent changes to your eyeglasses prescription.
  • You may get double vision in one eye.
  • Your near vision may improve for a short time if you get a cataract. This temporary improvement is called "second sight".

The vision loss from a cataract often happens slowly and may never become severe. Sometimes cataracts do not cause any vision problems

Surgery overview

Cataract surgery removes the lens containing the cataract from the eye and is performed by an ophthalmologist. In most cases, the lens is 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.

Cataract surgery is usually an outpatient procedure and 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.

There are three surgical techniques to remove cataracts.

Extracapsular surgery or standard extracapsular cataract extraction (ECCE) removes 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.

  • 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.

Phacoemulsification surgery (also known as Phaco or “small incision surgery”) is an advanced form of extracapsular surgery. Most cataract surgeries today use phacoemulsification. A smaller incision can be used because the lens is broken into fragments inside the capsule by ultrasound energy and removed by aspiration

  • 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. The cataract and lens pieces are removed from the eye using suction (aspiration).
  • An intraocular lens implant (IOL) may then be placed inside the lens capsule.
  • Usually, the incisions seal themselves without stitches.

An older technique called intracapsular extraction (ICCE) is seldom used today because more advanced methods exist. With this technique, the entire natural lens of the eye, including the back lens capsule, is removed. This procedure requires a larger incision and more sutures.

What To Expect After Surgery

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 one 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.

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

In most cases, cataract surgery is not urgent so you will have time to consider your options. 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.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 one year after surgery show that phacoemulsification works better than standard extracapsular cataract extraction (ECCE) to improve vision.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.


Less than 5 out of 100 people have complications from cataract surgery that could threaten their sight or require further surgery. The rate of complications increases in people who have other eye diseases in addition to the cataract.1

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).
  • Bursting (rupture) of the capsule and loss of fluid (vitreous gel) in the eye.
  • 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 terazosin) and blood thinners (such as warfarin) 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.

People usually need reading glasses (glasses for near vision) after cataract surgery, no matter which type of surgery is done. But some people may choose to have different lens implants (intraocular lens, or IOL) in their eyes so that one eye can be used for distance vision and the other for near vision (monovision). A type of IOL that allows you to see both distance and near vision is available. Talk to your doctor about the pros and cons of each type of IOL.

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.

Infants have the highest risk (almost 100%) for cloudiness in the back portion of the lens capsule following cataract surgery. If posterior capsule opacification develops after cataract surgery, a laser procedure or a vitrectomy that removes the posterior capsule may be needed. For that reason, most pediatric cataract surgeries remove the central portion of this posterior capsule during the first operation. This may allow better sight and reduce the need for laser surgery.

If a child has cataracts that are causing a lot of vision loss in both eyes, surgery on the second eye needs to be done within a few weeks. As in adults, only one eye is operated on during each surgery. This decreases the chance of complications occurring in both eyes at the same time.

Because of infants' rapid eyeball growth and for other reasons, some surgeons don't use IOLs in infants. Instead, an infant will wear a contact lens to replace the lens that is removed from the eye. If surgery can be delayed until the child is 1 to 2 years old, the surgeon may be able to use an IOL to replace the lens in the child's eye. Surgery cannot always be delayed, though, because of the risk of amblyopia and permanent vision loss.


  1. American Academy of Ophthalmology (2006). 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:

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