Cataracts from A to Z

This was once a very feared word ranking right up there with cancer. Cataracts meant severe loss of vision, maybe even blindness. Fortunately, with modern advances in medical science and surgical techniques, one does not have to tremble when they find out they have early cataracts. This article discusses cataracts in detail. I will tell you what cataracts are, why they form, and what they do to your vision. I will discuss what might help to prevent or slow down the progress of a cataract, and I will also discuss the removal of cataracts and the implantation of an artificial lens.

What are Cataracts and what do they do to your vision?

A cataract results when the lens of they eye loses its transparency. The lens is located behind the iris, or colored part of the eye. Its purpose is to allow us to focus at different distances. It is the lens that fails us in our forties and ultimately leads to the need for reading glasses. As we grow older, the lens will lose some of its transparency even though a cataract may not be actively forming. This loss of transparency is best indicated by the trouble many of us have with night driving as we get older. Cataracts often start in the sixties or seventies, but may occur earlier or much later in life. It is the most common eye problem we encounter as we mature.

Some cataracts start in the periphery of the lens and grow slowly towards the middle. A nuclear cataract will alter the central part of the lens and cause a yellowish brown appearance when I look into the eye. As a cataract matures, there is a gradual dimming of vision. You may feel there is a film before your eyes, and the glare from headlights at night may become a real problem. Eventually, the ability to see decreases until it becomes necessary to have the cataract lens removed.

Why Do Cataracts Form?

There are a few things that may cause cataracts. Some of the lesser causes of cataracts include injury and toxic exposures. Injuries where something penetrates the eye, and strikes the lens will almost certainly cause the formation of a cataract in time. A blunt injury to the eye, such as that from a racquet or tennis ball, may cause the formation of a cataract. Even though no penetration has taken place, the impact may push the iris (colored part) against the lens. This disturbs the outer membrane of the lens, often leaving an imprint of the iris on the front surface of the lens.

Toxic causes result from excess exposure to a cataract-producing substance. This may include medications such as steroids which are used to treat inflammation in the body. Anti-cancer and leukemia drugs may lead to the development of cataracts. Obviously the drug must be continued in this instance because of the need to eliminate the primary problem, which is the cancer or leukemia. Chemicals such as naphthalene (mothballs), copper, lead, silver and mercury when absorbed or ingested in excessive amounts may cause cataracts. Electric shock has also led to the development of opacities in the lens.

Excessive radiation in the form X-rays, gamma rays, microwaves and infrared light may lead to the production of cataracts. Ultraviolet light and its relationship to cataracts has been the topic of many scientific papers lately. Ultraviolet rays are invisible light waves which cause our skin to tan. UV radiation is a causative factor in the formation of cataracts. This is why UV inhibitors in spectacle lenses and wearing a brimmed hat outdoors are very important.

Without question the number one cause of cataracts is aging. By our sixties and seventies many of us are developing active cataracts in our lenses. By our late seventies and early eighties almost everyone has some form of cataract, but often times they are very slowly-progressing types that may not cause a problem with vision.

The actual mechanism of cataract formation is not clearly understood. We do know that the potassium is lost from the lens, while the sodium content increases. Calcium and protein content of the lens increases along with the water content. These changes seem to occur because the energy-transport mechanism of the lens slows down. This mechanism regulates the amounts of these different substances going in and out of the lens. As the proper balance of these substances gets out of kilter, the transparency of the lens is decreased and a cataract begins to form.

Like old Ponce de Leon, I do not think any of us have found the "Fountain of Youth." So there is very little we can do to prevent cataracts caused by the aging process. Fortunately, government regulations regarding safety in the workplace have helped to curtail excessive exposure to chemical, radiation and other cataract-causing substances.

What might help to prevent or slow down the progress of a cataract?

We have just reviewed what cataracts are and what causes them. Now we will consider the role of various nutrition therapies in the cure and prevention of cataracts. According to the book Cataract Breakthrough, certain processes take place in our lenses which causes the loss of transparency and eventual cataract formation. The changes occur as a result of changes in enzyme and energy-transport mechanisms which often result from age-related causes. According to Dr. Duarte, the author of the book, by using certain supplements in the diet one can cure, stabilize or slow the progression of cataracts. He advocates the use of Vitamins B2, C, E and other elements such as zinc and selenium. These nutrients help the lens to maintain the proper levels of desirable elements in the lens, thereby keeping the lens cataract-free.

A few years ago, I initiated a small research project to test the validity of Dr. Duarte's claims. Four of my patients, all with different levels of cataract development, took the recommended level of supplements. They were evaluated at six week intervals to check their prescription and how well they could read the eye chart with their new prescriptions. Subjective judgments such as can you see any better were not allowed since there are too many other variables such as light and the temporary physical status of the patient that might affect their opinions.

All four patients experienced a slight improvement when reading the eye chart. This improvement was not less than one line nor more than two. Often when a cataract is forming there will be an increase in nearsightedness. It would follow that if this therapy were "curing" the cataracts there would be a reversal of this nearsightedness trend. This never occurred.

One 64 year old patient, who had experienced a slight improvement in her vision from the supplements, had a sudden drop in her vision from 20/50 to 20/200. This occurred in a matter of a few months and while the patient continued with the nutrient therapy.

In conclusion, I believe it would be safe to state that no known nutrient-type therapy nor any other medical therapy will halt or cure the degenerative changes which occur in the human lens as a result of cataract formation. While some short-term improvement may occur, it is usually only a matter of time before enough undesirable body processes cause a significant reduction in visual acuity to indicate the need for cataract surgery. On the horizon, I see the actual causes of cataract being discovered. This will ultimately lead to the development of a pharmaceutical agent that will arrest the cataract-development process. This will allow the human lens to remain clear, giving the patient good, useful vision.

Removal of Cataracts

The surgical removal of the cataractous lens and the implantation of a clear plastic lens is one of the major breakthroughs in medicine over the past thirty years. Most cataract surgeries are done in a hospital operating room, but on an outpatient basis. There are a few freestanding cataract centers in northeast Ohio. Prior to the surgery it is necessary to measure the front surface curvature with an instrument called a keratometer. Also, the length of the eyeball is precisely measured using an ultrasound technique. These tests should be done twice and are necessary to make sure the proper powered replacement lens will be implanted in the eye.

The patient is asked to arrive at the hospital two hours prior to surgery for pretesting. These tests include a blood count, electrolytes and an EKG. The eye is also dilated as is done during a routine eye examination. During the surgery there are three nurses present to provide for your needs and to assist the doctor. The scrub nurse is sterile and provides the doctor with instruments as the surgery progresses. The nurse anesthetist keeps you comfortable and monitors your vital signs. At no time are you put to sleep. The circulating nurse is not sterile and is there to provide for the needs of the other three.

In the operating room an IV is established in the back of your hand. Through it several calming, numbing drugs are introduced into your body. These drugs give the patient a painless, carefree experience. The action of these drugs is immediate. Next, two injections are given to prevent you from moving your eyeball and lids during surgery. A Honan balloon is then placed on your eye and strapped around your head. When the balloon is inflated, it pushes against the eye. This helps reduce the pressure in the eye and also it helps to spread the anesthetic from the two injections. Betadine is used to sterilize the area around the eye. Then a drape with a hole is placed over your face leaving only the eye exposed. Lid retractors are used to hold the lids out of the way.

The surgeon makes a very small incision in the superior white part of the eye. Through this incision, he will gain access to the anterior segment of the eye where the lens is located. A substance called Healon is introduced into this incision. This viscous material protects the back surface of the front (cornea) of the eye. A planned circular tear of the anterior capsule of the lens is made with forceps. An ultrasonic instrument with a titanium tip is introduced into the chamber. This tip vibrates 40,000 times per second. This vibration causes liquification of the hard nucleus which is then aspirated (removed) from the eye. The remaining softer lens material is cleaned out using irrigating solution and suction. The back capsule is left intact in the eye to serve as a barrier between the front and back of the eye. It also serves as a bag to support the clear, new, plastic artificial lens. Before the lens is inserted, the back capsule needs to be polished to insure a clean surface. A clean, smooth surface helps to prevent an after or secondary cataract. More Healon is injected into the bag area to keep it open. The new, artificial lens is then placed into the bag. If an artificial lens is not used, the patient must wear a contact lens or very thick glasses. Fortunately today, almost all surgeries result in the implantation of an artificial lens. With today's modern surgical techniques, no sutures are needed to close the wound. The pressure dynamics within the eye keep the closed wound from leaking.

The actual surgery only takes about 30 minutes. By noon you are on your way home with a patch on your eye for protection and cleanliness. The patch is left in place until your first post-operative visit with the surgeon on the following day.

The vast majority of cataract surgeries result in a tremendous improvement in vision with little or no problems following the brief operation. Complications from infection or bleeding can result when surgery is performed anywhere in the human body. The eye because of its unique structure and function has its own group of potential complications.

Cystoid macular edema is a swelling of the central retina. The central retina provides us with our best vision. CME occurs in approximately 2% of the patients following cataract surgery. The primary symptom is blurred vision with a loss of often several lines (e.g. 20/20 to 20/40) on the visual acuity chart. The swelling and blurry vision may disappear on its own, or the CME may be self-limiting and not get progressively worse. Fortunately, with today's posterior chamber lens implants that are placed behind the colored part of the eye, we find less cystoid macular edema than in previous years.

Another possible complication following cataract surgery is the development of a secondary cataract. When the surgeon removes the cataractous lens, he leaves the back capsule in place to act as a barrier and also to hold the lens implant in place. In approximately 10% of the surgery patients this lens capsule will turn opaque because of the capsule cells trying to grow a new lens. In patients under 50 having cataract surgery, approximately 50% of them will develop secondary cataracts. Almost all secondary cataracts will develop within two years of the initial surgery.

The remedy for a secondary cataract that has significantly reduced vision is a laser. With an average of twenty low-power emissions from the laser, a hole can be made in the capsule that will readily pass light. It is a common misconception that a laser is used in the initial cataract surgery. The destruction of a secondary cataract is the only place where a laser is used in a problem pertaining to cataracts.

The final complication we will discuss is a retinal detachment. This complication is potentially the most dangerous. Retinal detachments occur in one to two percent of the cataract extractions. The lens of the eye acts to hold in place much of the gel-like material in the posterior part of the eye. Once the lens is removed, the material may move forward pulling tears in the retina which may lead to a detachment. If reattached quickly, serious permanent vision loss will be avoided.

With today's modern techniques, complications from cataract surgery are minimal. In almost all cases a dramatic improvement in vision is noticed soon after surgery.

Questions and Answers About Cataract Surgery

Q In the good old days we said the cataract must be "ripe" before it could be removed. What criteria do you now use to determine when a cataract should be removed?"

A When a person starts to modify his or her lifestyle because of poor vision, then it is time to consider cataract surgery. Driving is another important factor. Would a patient be a safer driver if the cataracts were removed?

Q How long does the surgery take?

A Most surgeries will take 35 to 45 minutes.

Q Are patients apprehensive when they are on the operating table?

A No. The patient is always awake, but calming medications are used and the patients are quite comfortable.

Q Does anything have to be done after the surgery?

A The eye needs to be protected at night while sleeping. This is done with a shield that is taped over the eye. This is only for the first week. Drops are also used to prevent infection and to help reduce inflammation from the surgery.

Q Is there ever occasion to replace an implant?"

A If the corrective power is inaccurate, a different implant may be necessary. A dislocated lens may also be an indication for changing an implant.

Q Is there much difference in recovery time after surgery?"

A The average total recovery time is four months, but many people are doing quite well after a few days. Some may take several months before any noticeable improvement is seen.

Q Are there any really adverse problems that occur during or after cataract surgery?"

A Yes, but fortunately they are pretty rare. The most common is a retinal detachment which occurs after approximately two percent of the surgeries. Endophthalmitis (infection of the inside of the eye) occurs in approximately one in one thousand surgeries. An expulsive hemorrhage, where bleeding causes the retina to be pushed forward from the back of the eye, is the most serious complication. Fortunately, it only occurs in about one in five thousand procedures.

I hope you have enjoyed this article and now understand more about this very common eye problem. If you have questions or comments, please call or e-mail Dr. Murphy at drmurphy@donaldmurphyod.com.
 
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