Once a clouded lens develops, surgical removal is the only remedy. Each year about 1.5 million cataract operations are performed, making it the most common operation in the country in people over 65. Cataract surgery may be the oldest procedure in the world having been introduced to Europe from India by Alexander the Great's army.
Naturally, cataract surgery has improved greatly since then. In the past, cataract surgery was not performed until the cataract had become well developed. Newer techniques, however, have made it safer and even more efficient to operate in earlier stages. In fact, modern cataract techniques not only remove cataracts but are also becoming important procedures for correcting astigmatism. Cataract surgery improves vision in up to 95% of cases and saves millions of Americans from blindness.
Nevertheless, considerable evidence suggests that, because of the ease and relative safety of the procedure, it may be performed more often than needed. Patients having operations now tend to have better preoperative vision than those operated on ten or 20 years ago. In a study of 800 cataract operations, a quarter of the patients said that clouding had had no obvious effect on their lives before the procedure.
Nonsurgical Measures for Managing Early Cataracts
Although surgery is the only remedy for cataracts, it is almost never an emergency. Most cataracts cause no problem other than reducing a person's ability to see, so there is no harm in delaying surgery.
Early cataracts may be managed with the following measures:
- Stronger eyeglasses or contact lenses.
- Use of a magnifying glass during reading.
- Strong lighting.
- Medication that dilates the pupil. (May help some people with capsular cataracts, although glare might be a problem with this treatment.)
It is important to note, however, that there are no treatments that will prevent cataract formation or progression or that make a cataract disappear.
Choosing Cataract Surgery
Advantages of Surgery. Cataract surgery is very successful. It has the following advantages:
- Nearly all patients enjoy better vision after surgery. Advanced procedures in lens development are allowing correction of astigmatism as well as cataract removal. (Patients with significant eye disease, such as glaucoma or corneal or retinal disease, may not experience the same degree of improvement.)
- Many people experience significant improvement in quality of life after the operation.
- Some studies indicate that better vision might even help slow down age-related health problems unrelated to the eyes.
Progression of Cataracts. Patients and their families usually have plenty of time to consider options carefully and discuss them with an ophthalmologist. There is no constant rate at which cataracts progress:
- Some develop to a certain point and then stop.
- Even if a cataract does progress, it may be years before it interferes with vision.
- Only in a very few, very rare circumstances is it necessary that cataract surgery be performed immediately.
Indications for Surgery
In general, surgery is indicated for people with cataracts under the following circumstances:
- The Snellen eye test reports 20/40 or worse, with the cataract being responsible for vision loss and glasses or visual aids no longer being helpful.
- Everyday activities have become difficult to perform to the point that independence is threatened. Questionnaires that assess the effects of cataracts on quality of life have been developed.
- The patient is at risk for falling in low light.
These guidelines are general, however. Whether surgery is appropriate or not further depends on the cataract patient's specific condition and needs. Some examples include the following:
- Even if the criteria for surgery are met, a very sick, very elderly person in a nursing home may have less need for sharp vision than an active younger adult. Among very elderly patients (85 and older), especially those with serious health problem, there are also higher risks for complications during surgery and poor outcomes afterward. Nevertheless, these cautions should not prevent the very elderly from having this procedure; vision improvement rates are still over 85%.
- Even if the criteria for surgery are not met, some people with eye tests of 20/40 or better might want surgery because of problems with glare, double vision, or the need to have an unrestricted driver's license.
- Even if the criteria for surgery are not met, if retinal disease is also suspected (usually a complication of diabetes), the physician may perform cataract surgery in order to have a clear view of the eye.
Because of the risks, albeit small ones, of poorer vision or blindness, no one should be forced to have cataract surgery if they don't want it or are not strong enough to undergo the procedure. If there are any doubts about whether or not to undergo cataract surgery, a second opinion should be considered.
Questions for the Ophthalmologist
The patient should ask the ophthalmologist the following questions before agreeing to cataract surgery:
- Is my cataract surgery an emergency?
- Are the cataracts the only cause of my poor vision?
- How much experience do you have with this procedure?
- Do I have other eye diseases that might complicate surgery or reduce my benefit?
- Do I have other health problems that might further complicate eye surgery?
- Will you be able to implant an intraocular lens?
- What type of procedure will you use?
- Will I have to stay in the hospital overnight?
- Afterwards, what are my chances of having poorer vision or becoming totally blind in that eye?
- How well should I ultimately be able to see out of the operated eye?
- How long will it take to heal?
- How long will it take to achieve my best eyesight?
- Will I have to wear glasses or contact lenses after surgery?
- When will I get my final eyeglass prescription?
- How soon after surgery will I be able to see well enough to go back to work? Drive a car? Return to full activity?
- What will the surgery cost?
Preparation for Surgery
Cataract surgery is now usually done as an outpatient procedure under local anesthesia and takes less than an hour. Preoperative preparations may include the following:
- Having a general physical examination is important for patients with medical problems but does not seem to be necessary or have any effect on surgical complications for most otherwise-healthy patients.
- The ophthalmologist will use a painless ultrasound test to measure the length of the eye and determine the type of replacement lens that will be needed after the operation.
- Topical application of so-called fluoroquinolone antibiotics (such as ofloxacin or ciprofloxacin) may be applied preoperatively to protect against postoperative infection.
- Most healthy patients are given either a local injection or topical anesthetic. The patients who report the least pain during the operation are those given a sedative followed by a local injection rather than just the topical agent.
- Some patients may require a general anesthetic, such those who are very anxious, those who are unable to cooperate with the surgeon, and those who are allergic to local anesthetics.
All cataract procedures involve removal of the cataract-affected lens and replacing it with an artificial lens.
Phacoemulsification. Phacoemulsification (phaco means lens, emulsification means to liquefy) is now the most common cataract procedure in the United States and account for 85% of cases. Benefits are greater than with standard extracapsular surgery, and it may be particularly beneficial for people with diabetes.
The procedure generally is as follows:
- The surgeon makes an incision, which is much smaller than with standard cataract extraction.
- Ultrasound is then used to break up the clouded lens into small fragments.
- The tiny pieces are sucked out with a vacuum-like device.
- A replacement lens is then usually inserted into the capsular bag where the natural lens used to be. In most cases, this is an intraocular lens (IOL), which is foldable and slips in through the tiny incision.
- Because the incision is so small, it is often watertight and does not require a suture afterward, particularly if a foldable lens has been used. One may be required if a tear or break occurs during the procedure or if an unfoldable lens is inserted that requires a wider incision.
||Click the icon to see an illustrated series detailing cataract surgery.
Most procedures now take about fifteen minutes, and the patient is usually out of the operating room in about an hour. There is little discomfort afterward and visual rehabilitation takes about one to three weeks.
Surgeons in the U.S. and Europe are currently investigating Microphaco, a new approach to cataract surgery that uses two smaller (micro) incisions. The smaller incisions measure about 1.6 mm compared to the traditional 3 mm. Experts say this procedure is expected to revolutionize refractive and cataract surgery.
Extracapsular or Intracapsular Cataract Extraction. The standard procedure has been extracapsular cataract extraction, but is generally used now only in patients who have an extremely hard lens. It typically involves the following steps.
- The ophthalmologist works under an operating microscope to make a small incision in the cornea of the eye.
- The surgeon then extracts the clouded lens through this incision.
- The capsule is left in place, which adds structural strength to the eye and enhances the healing process. (Less commonly, in intracapsular cataract extraction, the surgeon removes the lens and the entire capsule. There are greater risks with this procedure for swelling and retinal detachment.)
- A replacement lens is then usually inserted.
- A small suture is needed to stitch the incision together.
It takes about two to four weeks to completely restore vision.
Replacement Lenses and Glasses
With the clouded lens removed, the eye cannot focus a sharp image on the retina. A replacement lens or eyeglass are therefore needed:
Intraocular Lenses (IOL). In about 90% of cataract operations, an artificial lens, known as an intraocular lens (IOLs), is inserted. Until recently, IOLs used to employ a pair of little spring-loaded loops to hold the lens in place. Most IOLs are now foldable, which makes insertion easier. In fact, a prefolded lens is now available that unrolls to fit the eye as body temperature warms it.
Although all the lens materials are presumably chemically inert, there are some reports of specific problems, notably a risk for causing a reaction that leads to the development of secondary cataracts, a condition called posterior capsular opacification. IOLs are usually made of one of the following materials:
- Acrylic. The majority of IOLs are made from acrylic, which allows a controlled unfolding of the lens. Evidence now suggests that this material provides a better visual outcome and fewer complications than other standard IOLs.
- Polymethylmethacrylate (PMMA). Has the longest safety record. A PMMA IOL coated with heparin, a blood thinner, helps protect against the development of a secondary cataract after surgery.
- Silicone. Can be inserted through a smaller incision than other materials. It has the highest rates of secondary cataracts. Newer forms of silicon IOLs may pose a lower risk.
- Crystalens: The FDA approved the Crystalens IOL in November 2003. It is made from a proprietary form of silicone called Biosil. The Crystalens uses "hinges" that allow the lens to move, mimicking the eyes natural ability to focus automatically and seamlessly at all distances. Studies have shown that when used along with standard cataract removal methods, the Crystalens restored a patient's full range of functional vision, from distance to reading vision without total dependence on glasses or contact lenses.
- Tecnis Z9000: The Tecnis foldable IOL was specifically designed to improve functional vision of cataract surgery patients. Tecnis has a patented surface which reduces light scattering (spherical aberration) of the cornea, which can negatively affect vision. In April 2004, The FDA approved new labeling claims for Tecnis, allowing the product's manufacturer to market the lens as a way to improve the driving safety for millions of senior cataract patients. In clinical trials, simulated night driving and visual acuity (i.e., 20/20, 20/40, etc.) results were significantly better in eyes implanted with the Tecnis IOL. In addition, spherical aberrations were significantly less when compared to the traditional lens with the spherical optic.
- AcrySof Natural: The yellow-tinted Acrysof Natural IOL is the first foldable lens that filters ultraviolet and blue-light. Eliminating both UV and portions of the high-energy blue light help prevent retinal damage. This lens also conforms to the natural shape of the human lens capsule so it remains centered over the eye. The FDA approved the AcrySof Natural lens in June 2003.
Other materials are under investigation.
IOLs are designed to improve specific aspects of vision. The choices are as follows:
- Lenses that address a single fixed focal point. Such lenses are suitable either for reading or for distance vision, but not both. If a distance lens is implanted, the surgeon prescribes glasses or contact lenses for reading. If a reading lens is implanted, lenses for seeing distances will be prescribed.
- Lenses that address multifocal points. Multifocal lenses can focus at different points for both reading and distance vision. One study reported that more than 80% of patients with multifocal lenses were able to see 20/40 or better without correction. However, contrast may be reduced and some patients experience glare and halos, particularly at night.
- Lenses are available that will correct astigmatism after cataract surgery.
The patients and the physician must make these decisions based on specific visual needs.
Contact Lenses or Cataract Glasses. A few patients do not receive a new lens and rely solely on corrective eyeglasses or contact lenses. Such patients may include the following:
- Patients who are extremely near-sighted.
- Patients with other eye disorders.
In such cases, the patient typically returns to the ophthalmologist for a check up the day after surgery, and three additional check-ups are scheduled over a two-month period. The ophthalmologist can usually give a final prescription for eyeglasses or contact lenses about three months after surgery.
Choosing Contact Lenses. Contact lenses allow clear vision but do not magnify, so those who choose contact lenses after surgery may have to wear reading glasses. Contacts can be prescribed either for use only during the day or for extended-wear. Occasionally contact lenses cause problems, such as infection. Those who wear them should call their eye doctor if they have red or watery eyes, pain, or sensitivity to light.
Cataract Glasses. Until the advent of contact lenses, people who had cataract surgery had no choice but to wear glasses with thick lenses, sometimes called Coke-bottle glasses. These glasses have gotten thinner and lighter in recent years, but they may still be cumbersome. Cataract glasses are different from ordinary glasses and are sometimes difficult to adjust to. Images can seem distorted and may appear suddenly within the peripheral vision. Distances may be hard to judge.
Sometimes a patient has two cataracts and needs to wear glasses between the first and second operation. They are particularly troublesome during this period. The treated eye will see images magnified while the other eye will view them as they actually are, and the brain cannot blend the two images. This is a temporary state that is resolved by the second operation.
Complications of Cataract Surgery
Modern cataract surgery is one of the safest of all surgical procedures. Most complications, even if they occur, are not serious. They can include the following:
- Swelling and inflammation. Risk is about 1%. This complication is particularly harmful for patients with existing uveitis (chronic inflammation in the eye, which can be due to various conditions).
- Glare. Patients may experience glare after surgery from light scattering at the edges of the new lens, particularly with square-edged IOLs, which are typically used with posterior capsular cataracts. In most cases. This is a temporary problem and it resolves after a few weeks. In some cases, it persists and the patient requires a re-operation. Some research suggests that glare can be significant reduced by texturizing the edges of the square lens.
- Materials used in some lenses trigger an immune response in about half of patients. This causes inflammation and tiny deposits of tissue in the eye that lead to secondary cataracts--called posterior capsule opacification. Studies suggest that silicone implants pose the highest rates for inflammation and secondary cataracts, particularly in patients with other eye diseases. Newer silicon IOLs pose less risk. In one study, the lowest rates were with IOLs made of acrylic and heparin-coated PMMA.
- Retinal detachment. In rare cases, the retina at the rear of the eye can become detached. Risk is very low (0.1%), and phacoemulsification poses less of a risk for this than standard surgery.
- Atonia (loss of muscle tone that results in a disturbing glare). (Phacoemulsification poses less of a risk than standard surgery.)
- Glaucoma. This is an eye condition in which the pressure of fluids inside the eye rises dangerously. Risk is very low, but patients should be sure to avoid activities after surgery that increase pressure.
|Glaucoma is a condition of increased fluid pressure inside the eye. The increased pressure causes compression of the retina and the optic nerve which can eventually lead to nerve damage. Glaucoma can cause partial vision loss, with blindness as a possible eventual outcome.
- Infection. This is very rare (0.2%), but is devastating if it does develop.
- Blisters on the cornea. There is a higher risk of rupture with phacoemulsification but the risk is extremely low, particularly for experienced eye surgeons. In April 2004, the FDA approved the StabilEyes Capsular Tension Ring (CTR) to help support the eye's capsular bag during cataract surgery, especially in those with weak or broken eye fibers (zonules). A CTR is an open ring made of polymethylmethacrylate (PMMA). The ring goes into the capsular bag itself, stabilizing the eye.
- Bleeding can develop inside the eye. Risk is about 1% for minor bleeding and 1 in 10,000 for severe bleeding.
- An implanted IOL can become damaged or dislocated. Risk is very low.
- The surgery itself can produce vision loss or impairment. The risk for this is 1 in 1,000. (Phacoemulsification poses less of a risk than standard surgery.)
- Macular degeneration. Macular degeneration is a common cause of vision loss in the elderly, in which the retina breaks down. In one five-year study, people who underwent cataract surgery had twice the risk for progression of age-related macular degeneration. Interestingly, another study reported that cataract surgery significantly helped patients who had existing macular degeneration. More research is needed to refute or confirm this finding.
||Click the icon to see an image of macular degeneration.
Phacoemulsification does have some specific complications, although they are rare, particularly with experienced eye surgeons. They include the following:
- Rupture of the lens capsule.
- Loss of the lens nucleus into the eye fluid. (This will require removal by a specialist and may result in poorer vision.)
- Flying fragments of the lens can damage the cornea or threaten the retina.
- Pre- and postoperative changes in blood pressure, which are generally not a problem, should be observed carefully, since in some cases the changes may be extreme.
Of note, in about 30% of cases patients develop secondary cataracts within one to five years after either procedure, which require different treatment choices.
Preventing Infection and Reducing Swelling. The ophthalmologist may prescribe the following medications:
- A topical antibiotic (neomycin or, more effectively, gentamicin). This agent protects against infection.
- Corticosteroid eyedrops or ointments are often used to reduce swelling. Corticosteroids (commonly called steroids) are potent anti-inflammatory agents. However, they also pose a risk for pressure in the eye and infection. One study reported less visual sharpness with the use of steroids compared to antibiotics. Some newer steroids such as rimexolone, loteprednol, and fluorometholone may pose a lower risk for abnormal pressure.
- Nonsteroidal anti-inflammatory drugs, such as diclofenac, ketorolac, naproxen, and voltaren, also reduce swelling and do not pose the same risks as steroids. They may prove to be as effective, but more research is needed.
In one study, applying an ice pack for two hours immediately after phacoemulsification improved comfort level and reduced inflammation, even days after the operation. This simple procedure has no adverse effects and patients should discuss it with their surgeons before the operation.
Factors That Increase Risk for Complications. The risks of complications are greater for the following people:
- Patients who have other eye disease.
- People with diabetes. Intracapsular and extracapsular cataract extraction are known to pose a high risk for the development or worsening of retinopathy, a known eye complication of diabetes. Experts have hoped that phacoemulsification would pose a lower risk, but a 2001 study reported a high percentage (25%) of retinopathy progression after this procedure as well. The experience of the surgeon is critical to reduce the risk for this complication.
Those with other serious medical problems, such as heart or respiratory disease or diabetes, for which they may be taking strong medications. Either the diseases or the medications can increase the risks.
Returning Home and Follow-up Visits.
- Patients usually leave the surgical site within an hour of surgery. Cataract surgery almost never requires an overnight hospital stay.
- They need to have someone drive them home and stay with them for a few days until their vision is acclimated.
- The patient is usually examined the day after surgery and then during the following month. Additional visits are made as required.
- Vision usually remains blurred for a while but gradually clears, usually over a two to six-week period. (It can take longer.)
- When the physician decides the condition has stabilized, the patient will receive a final prescription for glasses or contacts.
Protecting the Eye. Postoperative protection of the eye typically involves the following:
- The ophthalmologist usually tapes a bandage over the eye to protect it during the healing process.
- When changing the bandage, the eye can be cleaned gently using a washcloth dipped in warm water without soap. A new bandage can then be positioned and taped.
- It is very important not to press or rub the eye during this procedure.
- An eye shield may be placed over the bandage at night.
Avoiding Glaucoma. Cataract surgery can cause glaucoma, a condition in which the pressure of fluids inside the eye rises dangerously. It is very important to minimize any activity that increases internal eye pressure. Postoperative cataract patients take the following precautions:
- Minimize vigorous exercise.
- Put on shoes while sitting and without lifting up the feet.
- Kneel instead of bending over to pick something up.
- Avoid lifting.
- Limit reading since it requires eye movement. Television is all right.
- Sleep on the back or on the unoperated side.
Treatment for Patients with Accompanying Eye Conditions
Cataracts and Glaucoma. For patients with both glaucoma and cataracts, experts recommend the following:
- In patients with cataracts and poorly controlled glaucoma, a two-step procedure for both eye conditions is needed. These are typically first trabeculectomy for glaucoma followed by cataract surgery. Fluid leakage and the presence of blood in the back chamber of the eye are potential complications of this combined procedure. Phacoemulsification has improved success rates and reduced high complication rates of the double procedure compared with extracapsular cataract extraction. New advances that replace trabeculectomy with nonpenetrating glaucoma surgery may prove to be beneficial.
- In patients who have cataracts plus either closed-angle glaucoma or open angle glaucoma that is stabilized with medication, the cataract may be able to be extracted and medication continued for the glaucoma.
- It should be noted that a major 2002 analysis suggested that the combined approach generally offers better control over eye pressure for patients with both cataracts and glaucoma. The best surgical procedure, however, is still uncertain.
Cataracts and Corneal Disease. Patients who have both cataracts and corneal disease may undergo one of the following:
- Combination Procedure. A single operation that combines three procedures. The combined procedure has been used since the late 1970s and employs extracapsular cataract extraction and intraocular lens insertion with corneal transplantation (called penetrating keratoplasty).
- Sequential Procedure. An operation that uses two procedures sequentially. The sequential option performs the cataract procedures and the corneal transplantation separately.
Recovery of vision is usually much more rapid after the combined procedure than after the sequential procedures. Performing the procedures sequentially may also carry a higher rejection rate of the implant, although a 2003 study found no differences in failure rates between the two approaches after a year.
In any case, many experts recommend that for most patients the sequential procedures may be the better option because it appears to have fewer of the following complications than with the combined procedure:
- Posterior capsule rupture.
- Eye fluid loss.
- Postoperative refractive errors, which result in abnormal distribution of light patterns.
The rate of these errors still depends on the skill of the surgeon and the power of the implanted lens no matter what approach is used.
Secondary Cataracts (Posterior Capsular Opacification) and Their Treatments
Secondary cataracts (posterior capsular opacification). About 30% of patients who undergo extracapsular cataract surgery develop a secondary "after-cataract" called posterior capsular opacification. Posterior capsular opacification generally occurs because of the following events:
- After surgery, there are still some natural lens cells left behind that proliferate on the back of the capsule.
- The capsule gradually becomes cloudy and interferes with clear vision the same way the original cataract did.
According to a 2001 study, the probability of developing a secondary cataract was 6% at one year, 15% at two years, 23% at three years, and 38% at nine years. The risk is lower with phacoemulsification. Secondary cataracts are more likely to occur in younger patients, in those with diabetes, or when cataract surgery is combined vitrectomy (clearance of debris from the fluid in the eye).
Preventing Posterior Capsular Opacification. Studies suggest that acrylic lenses pose the lowest risk for posterior capsular opacification. A number of substances to prevent posterior capsular opacification are under investigation, including tranilast eyedrops, new lens materials, special capsular rings inserted during phacoemulsification, and new coatings on the implanted lens (e.g., thapsigargin, a plant-derived substance). One interesting investigative approach is called bag-in-the-lens implantation, which involves inserting the lens capsule into the IOL, rather than the other way around. In one small study, no patients developed secondary cataracts after this procedure.
Treatment Decisions for Cataracts in the Second Eye. If a person has a cataract in a second eye, the issues for decision making are the same as for the first eye. The time of the procedure in the case of two cataracts is unclear. Physicians have long recommended that surgery on the second eye should be postponed until the first eye has healed and the results known (about a year).
One study has called this recommendation into question. It was conducted in England, where for budgetary reasons, there are long waits for second-eye cataract surgeries. In the study, patients who waited seven to 12 months for the second-eye surgery reported significant difficulty in reading and performing ordinary tasks during the waiting period. Only 1% of patients who had the second surgery within six weeks reported having trouble seeing. In addition, 70% of those who waited experienced problems in depth perception, which can cause difficulty in walking and driving; only 12% who didn't wait reported this problem. Patients with double cataracts should discuss all options with their surgeon.
Treatment for Posterior Capsular Opacification. The standard treatment is laser surgery known as a YAG capsulotomy. (Capsulotomy means cutting into the capsule, and YAG is an abbreviation of yttrium aluminum garnet, the laser most often used for this procedure.)
- This is an outpatient procedure and involves no incision.
- Using the laser beam, the ophthalmologist makes an opening in the clouded capsule to let light through.
- After the procedure the patient should remain in the doctor's office for an hour to be sure that pressure in the eye is not elevated.
- An eye examination for any complications should follow within two weeks.
Complications. Laser surgery has become so commonplace that some ophthalmologists use it after cataract surgery to prevent later clouding. However, laser surgery carries its own risks and possible complications, similar to those of cataract surgery itself, and can also lead to poorer vision or blindness. About 1% of laser surgery patients develop a detached retina, which is much higher than the risk from the original cataract surgery.
||Click the icon to see an image of a detached retina.
In some people, particularly those with glaucoma or who are severely nearsighted, the pressure in the eye may spike after laser surgery. Certain agents used for treating glaucoma, such as dorzolamide (Trusopt) or apraclonidine (Iopidine), may helpful for preventing this occurrence. It is strongly recommended, however, that this surgery not be performed to prevent a secondary cataract, but only if the lens capsule clouds up again.
Treating Cataracts in Children
Treatment of infants first depends on whether one or both eyes are affected:
- For infants born with cataracts in one eye, the American Academy of Ophthalmology recommends surgery as soon as possible, by four months or ideally even earlier. The procedure is followed by contact lens correction and patching of the unaffected eye. Although this approach is successful in many cases, some children still become blind in the affected eye. There is also a high risk for glaucoma after surgery.
- In infants with cataracts in both eyes, surgery is not always an option. In some cases, it may be performed sequentially, with the second eye operated on a few days after the first. Phacoemulsification appears to pose a much higher risk for secondary cataracts than standard lens removal.
Toddlers and Older Children
Intraocular lens replacement is now becoming standard treatment for children two years and older. Although secondary cataracts are common. Surgery is not usually performed in children over a year who have abnormally small eyes.