Cataract Surgery - Cataract: The Aging Eye Preventing And Treating Eye Disease

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Cataract surgery

Cataract surgery is the most common type of eye operation performed in the United States, with about 1.5 million Americans undergoing the procedure each year. Once an inpatient procedure requiring up to a week of hospitalization, today cataract surgery is performed under local anesthesia on an outpatient basis and is considered one of the safest surgeries. Most ophthalmologists are trained to perform cataract surgery or will refer you to someone who is. Ask around to find an experienced surgeon to guide you through the preparatory, operative, and postoperative stages.

The vast majority of patients have an artificial intraocular lens implanted to replace the eye's natural lens, which is removed during surgery; nearly all patients see more clearly afterward. Rarely, patients may have conditions that dictate against intraocular lenses or, also rarely, the implant may need to be removed if it dislocates or is displaced by injury. In such cases, the doctor will prescribe eyeglasses or contact lenses to correct postoperative vision.

Unlike some other eye surgeries, cataract surgery does not use lasers, except in some follow-up procedures. To remove the lens, the surgeon makes a tiny incision in the eye, a delicate procedure done with the aid of microscopes. The doctor may choose from several procedures for extracting the lens.

Phacoemulsification. This operation is the technique most often used today for cataract surgery. Its chief advantage is that it requires only a tiny incision, about one-eighth inch long, on the side of the cornea. This incision is so small and is constructed in such a manner that it often needs no stitches and heals rapidly.

After making the incision, the doctor uses a small needle-like probe to direct high-frequency sound waves at the lens. This breaks the lens up into small pieces, which are then aspirated through the probe (see Figure 5). The outer lining of the lens capsule (the membrane that surrounds the lens) is left behind to provide support for the artificial lens implant.

Figure 5: Removing a cataract In the most common method of cataract surgery, called phacoemulsification, the ophthalmologist removes the clouded lens [(A) and (B)] by breaking up the nucleus of the lens with ultrasound waves (C) and suctioning it out (D). A new plastic lens (rolled up like a taco) is inserted (E) and springs open to fill the cavity (F).

The doctor usually replaces the clouded lens with a clear artificial lens made of silicone or acrylic that has been developed specifically for this method. This type of lens is smaller than a dime and folds to fit through the incision. Once in place inside the lens capsule, it opens fully. In some cases, the surgeon may decide to use a rigid plastic lens instead; to do this, the surgeon enlarges the incision to insert the implant. Depending on the length of the incision, a stitch or two may be necessary.

Phacoemulsification offers good long-term results and is successful without any complications in 97%–98% of all cases done by an experienced surgeon.

Extracapsular surgery. This older technique is typically used for very dense or hard cataracts and in other special circumstances. An incision of about three-eighths of an inch is made under the upper eyelid, where the sclera and cornea join. After making the incision, the surgeon opens the lens capsule and removes the harder, central portion of the lens, usually in one piece. The softer part of the lens is then gently vacuumed out with a suction instrument. The outer part of the lens capsule is left undisturbed, providing support for a replacement lens. After putting in the new lens, the surgeon stitches up the incision.

The main difference between extracapsular surgery and phacoemulsification is that with "phaco," most patients can resume their normal routine sooner, because the smaller incision heals faster. Over all, either procedure restores vision to 20/40 or better in more than 90% of all cases.

Intracapsular surgery. In this procedure, which is rarely used today, both the lens and the capsule are removed. Intracapsular surgery is generally reserved for cases in which the lens has dislocated because of either injury or an accompanying disease. In this surgery, the intraocular implant generally rests in front of the pupil or is secured with stitches to the eye wall.

Replacement lenses

Years ago, before lens implants were available, people often had to wear thick magnifying glasses in order to see after cataract surgery. These glasses, called aphakic spectacles, are seldom used today, because most people who undergo cataract surgery now have an artificial lens permanently fixed in their eye, which produces better vision. People who had cataract surgery before implants were available and those with eye diseases that make them poor candidates for a synthetic lens are often fitted with contact lenses, an excellent visual aid.

Intraocular lenses implanted as part of cataract surgery require no special care. The type prescribed depends on your particular situation. Most often, the implant is a posterior chamber lens; that is, it is slipped in behind the iris, within the portion of the lens capsule that remains after surgery. When it is inserted in front of the iris, as might occur when the capsule is faulty, it is called an anterior chamber lens. In either case, tiny plastic loops hold the implant in place.

About 95% of people who get standard intraocular lenses find their vision restored to what it was before the cataract developed. Still, after cataract surgery and insertion of a standard lens, you may need to wear glasses for reading or distance vision. The newer accommodative and multifocal lenses described below provide an option if you would like to decrease your dependence on glasses after cataract surgery.

Accommodative and multifocal intraocular lenses. Two newer types of lenses are available for implantation during cataract surgery. These lenses produce similar results but work in slightly different ways. Accommodative intraocular lenses, also known as variable focus lenses, move in response to your eye's own muscles to adjust for near, intermediate, and distance vision. Multifocal lenses include corrections for near, intermediate, and distance vision within the same lens (similar to the lenses available for some eyeglasses). Be aware that you may have to learn how to use the lenses after they are implanted, so ask your doctor for instructions or training.

Although these lenses may not provide you with 20/20 vision, they do generally decrease dependency on glasses after cataract surgery. The newer accommodative and multifocal lenses have generated a lot of interest, especially in people with presbyopia, who would normally still need reading glasses after cataract surgery. Although accommodative and multifocal lenses are not yet used routinely in cataract surgery, it is likely that their use will increase as the technology improves.

The FDA approved the first accommodative intraocular lens for cataract surgery, Crystalens, in 2004, and approved two multifocal lenses, ReZoom and AcrySof ReSTOR, in 2005. Although these lenses work in different ways, so far the research has not shown one type to be better than another. Because this technology is rapidly evolving, it's best to talk with your ophthalmologist for a recommendation.

One issue to keep in mind is out-of-pocket costs, especially if your insurance plan does not cover the newer accommodative or multifocal lenses. Medicare used to pay for cataract surgery only if standard replacement lenses were implanted. That changed in 2005, when federal officials agreed that Medicare would pay for cataract surgery involving accomodative or multifocal lenses, as long as the beneficiary pays an additional fee to cover the lenses themselves. Because prices and insurance policies change regularly, talk with your doctor about how much a cataract operation using these newer lenses will cost before deciding to go ahead with it.

Preparing for cataract surgery

Before surgery, the ophthalmologist measures the curvature of your cornea and the length of your eye to calculate the power of the implant you need. Your doctor performs a general medical exam and may request tests to assess your overall health.

It's a good idea to mention any medication you are taking on a regular basis. In most cases, it is still possible to have cataract surgery, but you may need to stop taking certain drugs before the surgery to avoid possible complications. For example, your doctor may ask you to avoid aspirin and other drugs that have an anticoagulant (blood-thinning) effect, especially if the surgery is the type involving the larger incisions, because these drugs increase the risk of bleeding during surgery. You may also have to stop taking tamsulosin (Flomax), a medication that relaxes the muscle around an enlarged prostate so that it is easier to urinate, because this drug can cause the irises to flutter during cataract surgery, raising the risk of complications. Depending on your medical situation, your doctor may prescribe antibiotics, anti-inflammatory drugs, or both before the surgery.

During and after surgery

Local anesthesia keeps the eye comfortable and immobile during surgery. The entire procedure usually lasts less than half an hour, during which you may see light, hear noises, and be aware of the presence of the surgical team. However, you probably will not see formed images, and you may not be able to tell whether your eye is open or closed. Most people do not have pain of any sort during the procedure.

Once the operation is complete, the surgeon may cover the eye with a bandage or shield, which may be removed later that day or the following day. Typically you will be discharged after you rest for a while in the recovery area, but you will need someone to drive you home. Reading and watching television are permitted almost immediately. Although it's a good idea to take it easy, most people can resume normal activities within a few days. Check with your doctor, however, before doing anything strenuous.

Vision usually improves immediately following cataract surgery. For some, vision may be excellent within hours. For others, it may take several days or even a few weeks to return to normal. This longer interval does not necessarily indicate any complication or failure of the surgery. During the healing process, you may be surprised by changes in color: Because the clouded lens, which commonly filters out some colors, has been removed, colors may appear more luminous or seem to have a bluish glow. Spending time in bright sunlight may give objects a reddish afterimage when you come indoors.

Sticky eyelids, itching, sensitivity to light, and mild tearing are perfectly normal after surgery, but severe pain and sudden changes in vision are unusual and warrant an immediate call to your doctor. Patients who suffer minor discomfort can take a non-aspirin pain reliever such as acetaminophen (Tylenol) every four to six hours. Within a day or two, any discomfort should subside on its own.

The ophthalmologist will schedule several postoperative visits: the day after surgery, after about a week, at three to four weeks, and then usually six to eight weeks later. The doctor will examine your eye, test your visual acuity, and measure eye pressure. Corrections for eyeglasses will probably not be prescribed until three to six weeks following surgery.

Self-care

Once at home, you will use antibiotic and cortisone drops or ointment to prevent infection and reduce inflammation. To prevent infections, wash your hands thoroughly before applying the drops and avoid touching the bottle tip to your eye. Because the eye is sensitive after surgery, avoid rubbing or touching your eye, and guard against any sudden movement that could jar your head. To avoid accidental rubbing of your eye while you are sleeping, you may need to wear a protective metal eye shield at night for a few days or weeks.

Your doctor or health professional will show you how to clean your eyelids, which may become crusted from discharge. Many people prefer to wear medium-density sunglasses when outdoors to screen out the glare, even though most implants have ultraviolet blockers (see "Investing in the right sunglasses," below).

Make sure you understand all of your doctor's postoperative care instructions. It's important that you follow these instructions carefully to help ensure a full and rapid recovery. Discuss any questions you have with your doctor.

Possible complications

More than 98% of people who undergo cataract surgery have improved vision afterward, assuming they have no other limiting eye disease, and most have an uneventful recuperation. Complications, mild or severe, are extremely rare, but they need immediate medical attention.

Eye infections after cataract surgery occur only once in several thousand operations. However, if a person develops an infection inside the eye, vision — and even the eye — could be lost. Most ophthalmologists use antibiotics before, during, and after surgery to minimize this risk. Surface inflammations or infections usually respond well to medication. Intraocular inflammation without infection, which may occur in response to surgery, is usually minor and can be treated with postoperative steroids.

Although uncommon, a slight leak in the incision may occur, creating a greater risk for infection inside the eye. The doctor may apply a contact lens or a pressure bandage over the eye to promote healing, but sometimes the wound has to be reclosed with a stitch.

Pronounced astigmatism, which causes blurred vision, develops in some individuals after surgery because of swelling of the tissue or tight stitches (if stitches are used) that pull on the cornea and distort its shape. After the eye has healed from the operation, swelling diminishes and any stitches may be cut. This usually corrects the astigmatism. In some people, cataract removal can relieve existing astigmatism, as incisions may be designed to adjust the cornea's shape.

Bleeding within the eye is another potential problem. This rarely occurs in phaco procedures, because the smaller incision of this procedure is placed in the clear cornea, in front of the blood vessels, and no blood vessels are cut inside the eye. Even bleeding caused by larger incisions may stop automatically without causing any damage. Hemorrhaging from the choroid in the back of the eye is a rare but serious cause of vision loss.

Secondary glaucoma, which is usually temporary, may be caused by inflammation, bleeding, adhesions, or other factors that increase pressure inside the eye. Glaucoma medications can usually control the pressure, but this complication sometimes requires laser or other surgery. Retinal detachment occurs infrequently; when it does happen, it requires surgical repair.

On occasion, tissues of the macula — the central part of the retina — may swell for one to three months after cataract removal. One symptom of this condition, called cystoid macular edema, is blurring of central vision. An ophthalmologist can usually diagnose it with special testing and can often treat it successfully with medication.

Another rare complication is pseudophakic bullous keratopathy, the development of corneal edema (fluid buildup, leading to clouding of vision). This may occur months to years after cataract surgery and sometimes requires a corneal transplant. In fact, corneal edema following cataract surgery once accounted for about one-third of all corneal transplants in the United States. With the advent of better cataract surgery techniques and implantable lenses, the likelihood of experiencing corneal edema after cataract surgery has decreased dramatically; it is now estimated to affect 0.1% of people who have cataracts removed.

In rare cases, the implant may become displaced. If this happens, you might notice blurred vision, glare, double vision, or fluctuating vision. If this seriously impedes vision, your ophthalmologist can reposition the implant or remove it and replace it with another one.

In 30% of all cataract operations, the outer covering of the lens capsule that was left in the eye to support the implant becomes cloudy sometime after surgery, again causing blurred vision. This problem does not mean the whole cataract has grown back; the cloudiness affects only a tissue membrane, not the replacement lens. If the condition inhibits clear vision, it can be treated with a technique called YAG laser capsulotomy. (YAG stands for yttrium-aluminum-garnet, a type of laser.) In this procedure, the ophthalmologist uses a laser to create an opening in the center of the opaque capsule to allow passage of light. This procedure is quick and painless, and it requires no incision; it can be done in an ophthalmologist's office or outpatient clinic.

Last updated:	June 19, 2007