Cataract Extraction and Lens Replacement Surgery Definition

Cataract Extraction and Lens Replacement surgery is an operation to remove the lens from the eye after a cataract (cloudy occlusion in the lens) forms and replace it with a prosthetic intraocular lens (IOL). Ophthalmologists can extract a cataract at any stage of its development.

The vast majority of people who undergo cataract extraction fully recover without complications and experience visual acuity correctable to 20/40 or better.

Surgical Procedure

Cataract extraction is nearly always an outpatient surgery performed under local anesthetic and a mild general sedative for comfort.

There are three surgical procedures for cataract extraction. Each takes 20 to 30 minutes for the ophthalmologist to complete. Many variables influence the ophthalmologist’s choice for which to use.


The most commonly performed cataract extraction procedure is phacoemulsification, which requires a tiny incision into the capsule containing the lens. The ophthalmologist first uses ultrasound to liquefy the central nucleus (inner, gelatinous portion of the lens) and then uses aspiration to remove it.

Last the ophthalmologist removes the cortex (outer layer of the lens) from the capsule in multiple segments.

Extracapsular cataract extraction

The extracapsular cataract extraction procedure requires a slightly larger incision in the capsule, through which the ophthalmologist removes the central nucleus of the lens intact, then removes the cortex in multiple segments.

Lens replacement

After extracting the cataract, the ophthalmologist inserts either a monofocal or multifocal IOL to give the eye the ability to focus. Contemporary lens designs allow the ophthalmologist to fold the lens, insert it into the lens capsule through the tiny incision used to extract the cataract, and unfold the IOL to place it in position.

restores vision
improves quality of life
postoperative pain and swelling (uncommon)
postoperative infection (uncommon)
retinal detachment (rare)

Risks and Complications

Most ophthalmologists prescribe antibiotic and anti-inflammatory eye drops applied to the eye for four to six weeks following surgery, and recommend wearing dark glasses in bright light to help protect the eye from light sensitivity. Swelling and irritation of the tissues around the operated eye is normal in the first few weeks following surgery.

Clear vision may take four to six weeks, though many people experience dramatic improvement immediately. Though the short-term risks of cataract extraction and lens replacement are minor, retinal detachment can occur months to years following surgery.

Cataract extraction is a permanent solution for cataracts. Once removed, cataracts cannot grow back. Some people do develop a complication called posterior capsule opacity, in which the membrane behind the IOL becomes cloudy (opaque).

This is a complication that results when residual cells that remain after removal of the lens begin to grow across the membrane, causing the membrane to thicken. A follow-up procedure, either yttrium-aluminum-garnet (YAG) laser capsulotomy or conventional surgery, is necessary to remove the membrane.

Outlook and Lifestyle Modifications

About 90 percent of people experience vastly improved vision after cataract extraction. However, other eye problems or underlying conditions (such as retinopathy of diabetes) can affect the quality of vision.

Many people do need eyeglasses after cataract extraction, as the IOL does not adjust for focus as does a natural lens. It is important to see the ophthalmologist for follow-up and routine eye care as recommended.


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