Kentucky Eye Institute

The following cataract questions were asked during February 1996 and have been answered by an American Academy of Ophthalmology member.

1. Is there a connection between tamoxifen and cataracts? I have heard it debated -- pro and con! What's your opinion?

2. Doctors locally advertise one stitch or no stitch, laser, sound waves, etc. Please outline the surgical options presently available. Also, what is the newest procedure for removing cataracts?

3. Does the surgeon ever use a stitch to reduce the degree of astigmatism which may follow this procedure? I am assuming no stitch is required to close the incision.

4. What effect does cataract surgery have on people with increased risk of retinal detachment (genetic or otherwise)? Are there any specific things the doctor or patient should be aware of? What are the long-term effects of living without a lens (for example, in a severely myopic person where vision is close to normal without it)? My interest in these questions is in relation to Stickler Syndrome.

5. What is the best lens for implanting? Acrylic or silicone? What problems are associated with each?

6. My mother-in-law has been told she has cataracts and will be getting another checkup in six months, at which time they will determine when to schedule her for surgery. For the past year she has had excessive tearing which is driving her to distraction. Nothing has helped. Are the cataracts causing the tears?

7. My dad, 84 years, is scheduled for cataract surgery in March. He has dry eyes and has lost eyesight in one eye due to cornea melt and other problems. His remaining eye checks out okay except for 20/80 vision due to cataract. We are concerned whether there could be any complication during or after surgery from dry eyes. He also had rheumatoid arthritis but is no longer active.

1. Is there a connection between tamoxifen and cataracts? I have heard it debated -- pro and con! What's your opinion?

The Physician's Desk Reference states that visual disturbances including corneal changes, cataracts, and retinopathy have been reported in patients receiving tamoxifen. This does not necessarily mean that tamoxifen caused these changes, however. An association or lack of association between tamoxifen and cataracts is difficult to prove or disprove. Nearly all people develop cataracts to some extent as they age, and these cataracts get progressively worse as time passes. The majority of patients on tamoxifen are older women, and already have cataracts to some degree just because of their age. Therefore cataracts are seen in many people who are taking tamoxifen, and since these people get older while taking the drug, their cataracts get worse due to their advancing age. It is very difficult to know whether tamoxifen plays a role in this worsening. There is not very much literature on the subject. Tamoxifen does appear to cause cataracts in rats, and there are possible biochemical mechanisms by which it could cause cataracts. In humans, however, a cause and effect relationship has not been convincingly demonstrated.

2. Doctors locally advertise one stitch or no stitch, laser, sound waves, etc. Please outline the surgical options presently available. Also, what is the newest procedure for removing cataracts?

Nearly all cataracts today are removed by extracapsular surgery, in which the posterior capsule of the natural lens is left in place to support the plastic replacement lens which is implanted at the time of surgery.

There are two types of extracapsular surgery.

In planned extracapsular surgery the nucleus of the lens, which is too hard to simply remove by aspiration, is taken out in one piece, and the softer parts of the lens are then aspirated.

In phacoemulsification the hard nucleus is broken up by ultrasonic fragmentation (using sound waves) within the eye, and can then be aspirated. This allows a smaller incision to be used. Phacoemulsification has gained in popularity in recent years, and is now the most common form of cataract removal in the United States. This procedure has been used for approximately 25 years, although recent advances and refinements have made it safer and more effective than previously. Although not new, this would still be the "newest" procedure for cataract removal.

Both "one-stitch" and "no-stitch" surgery are just variants of phacoemulsification. The incision used in the surgery may be placed in one of several locations and the architecture of the incision may vary as well. The same incision may be "no-stitch" if the incision is watertight following surgery, or "one-stitch" if it is not, and requires a stitch to make it so.

The incision size for phacoemulsification is approximately 3.0 millimeters in width. If a lens implant which can be folded is used following removal of the cataract, this incision may not have to be enlarged. If a lens is used which cannot be folded, the incision must be enlarged to 5.0 or 5.5 mm. A larger incision is more likely to need a stitch. In addition, some surgeons simply prefer the safety of having the incision sutured, even if the incision is already watertight. The best procedure for a patient is usually the one with which his or her ophthalmologist feels the most comfortable, since these variations of cataract surgery are all quite effective.

Despite some public misconception, laser is not an option for removing cataracts at this time. There are laser devices for cataract removal under investigation, but none are approved by the Food and Drug Administration. Even the experimental devices are quite different from what one might imagine for use in a laser cataract surgery. In these devices a laser is used to break up the nucleus of the cataract into pieces small enough that they can be aspirated from the eye, in the same manner that sound waves are used in phacoemulsification. Thus, an incision still needs to be made, and the lens material removed from the eye. The proverbial "ZAP" of the laser and the cataract is gone while the patient sits in the chair will never happen, since a very small incision will always be needed to physically remove the cataractous lens material.

The YAG laser is used following cataract surgery if the posterior capsule of the lens, which supports the lens implant, becomes cloudy. This indeed is a procedure in which the patient sits in the chair and the vision is quickly cleared by the laser. It is not used to remove the cataract itself, however.

3. Does the surgeon ever use a stitch to reduce the degree of astigmatism which may follow this procedure? I am assuming no stitch is required to close the incision.

When a cataract is removed, one or more stitches can be used to close the incision, and these can indeed modify astigmatism. The most commonly used suture in cataract surgery is nylon. Although nylon is very inert, the body does eventually manage to degrade it, and any modification of the astigmatism would disappear at that time. This usually happens by a year following surgery. A more effective method of altering astigmatism is to place the incision in a location in which the effect of the incision itself reduces the astigmatism, and this is commonly done. Another way to reduce higher amounts of astigmatism is to make extra partial-thickness incisions in the cornea, either at the time of the surgery, or at a later date. This procedure is called astigmatic keratotomy.

Cataract surgery has long been known to increase the risk of retinal detachment. This risk is less now with extracapsular surgery, in which the posterior capsule of the lens is left in place, than it was when the entire lens was removed. This type of surgery is by far the predominant form in the United States at this time.

People at increased risk of retinal detachment include those who are very nearsighted (myopic) and those who have any of the vitreoretinal syndromes, such as Stickler Syndrome or Wagner's disease. Since these people are at a much increased risk of detachment anyway (greater than 50% for Stickler Syndrome), addition of another risk factor increases the likelihood even more. These people need to have regular retinal examinations and seek medical help immediately if they have any disturbing symptoms, such as new floaters, lightning flashes, or shadows and curtains covering the vision.

5. What is the best lens for implanting? Acrylic or silicone? What problems are associated with each?

There are three materials presently used for intraocular lenses, polymethylmethacrylate (PMMA), silicone, and acrylic, with other materials under development. None of these materials is clearly superior to the others. Each has advantages and disadvantages. PMMA has been used the longest by far, and thus has the best safety record. It must be implanted through a larger incision than the other materials. Silicone and acrylic can each be placed through a smaller incision than PMMA. Acrylic affords a very controlled unfolding of the lens, but silicone can go through a smaller incision than acrylic.

Today's intraocular lenses are very safe and effective. Most problems after surgery are related to the eye's reaction to the surgery itself, to problems arising during the surgery, or to positioning of the lens implant, rather than difficulty with the design of the lens or the material of which it is made. All of the available lens materials perform admirably.

The cataracts are probably not causing the tearing. Although cataracts could cause tearing under certain visually challenging circumstances, such as looking into the bright sun, most of the time they would not cause tearing. The tearing may be due to various aging changes of the lids, and would probably not be helped by cataract surgery.

Dry eyes can certainly cause problems at any time, and the eye is particularly vulnerable after any surgery. Most dry eyes do well with cataract surgery, however, and the dry eye is usually not a problem. The corneal melt in the other eye is more likely related to the rheumatoid arthritis, which will also cause the dry eyes. With this history in the other eye, the rheumatoid disease should be completely inactive before attempting surgery on the remaining eye.