By Dr. George L. Spaeth

Millions of people use eye drops to treat their glaucoma, and in most cases the drops don't cause serious problems. But heart attack, impotence, death due to stopping breathing, blood cells not being manufactured, retinal detachment, kidney failure, eyelids growing together, and many other problems just as important have been caused by medications used to treat glaucoma. Patients need to know this.

Less serious problems such as fatigue, forgetfulness, red eyes, a bad taste in the mouth, shortness of breath, bowel spasms occur routinely in people who to take medications for their glaucoma. In fact, over two thirds of those using glaucoma medications will have some type of side effect. In most cases the side effects are tolerable, and are an acceptable price to pay for the benefit that results from the medication. But, for that to be the case, patients have to be aware of the nature of the problems and the nature of the benefits so they can decide whether the potential benefit is worth the potential risk.

How Eye Drops Work

Eye drops contain substances that have powerful effects: adrenaline (affects the heart and blood vessels), pilocarpine (makes glands secrete and muscles in the eye, bowel, and bladder contract), beta-blockers (make breathing harder and blood pressure lower), and carbonic anhydrase inhibitors (depress one of the widespread enzymes in the body), etc., etc.

Placing an eye drop in the eye is not like dropping water on the skin. The surface of the eye is rich in small blood vessels, so that substances placed in the eye are quickly absorbed directly into the bloodstream. In contrast, when a pill is swallowed it has to pass through the stomach, into the bowel, and then to the liver, where it is often changed, or "detoxified." Placing a drop in the eye more directly affects the blood vessels, the heart, the brain, and other tissues of the body than swallowing a pill.

Can Harm Be Avoided?

One of the principles that's taught to developing physicians is " primum non nocere," or "first, do not harm." It was taught 2,500 years ago, and it's still taught today, although it is an increasingly difficult principle to uphold.

Virtually any action doctors or others take has multiple effects, some of which are harmful. We discipline a child because we wish him or her good, yet there is some harm involved in every disciplinary action. We "harm" our ability to do what we want by putting funds to be used for enjoyment into a bank account, or, viewed the other way around, we harm our bank account (essential for our future well being) by utilizing funds to enjoy ourselves. We harm fruit trees and grapevines by pruning them severely in order to cause them to bear better fruit.

The principle is obvious and elegantly expressed in the ancient Chinese symbol of the subdivided circle, one part being yin, and the other, yang, indicating there are contrasting aspects to everything that exists, including, for purposes of this discussion, medical treatments (Figure). There is no "gain" in one aspect without "loss" in another. For example, there is the potential for harm even in some of our safest treatments, such as utilizing milk to treat stomach ulcers. When milk is taken in large doses, especially when combined with the antacids frequently utilized to treat stomach ulcers, kidney stones can result.

Since, then, it is virtually impossible to "do no harm," the challenge is to "make the punishment fit the crime." While the theoretical goal is to "do no harm," in practice both the doctor and the patient must realize they have to accept some risk if they want any benefit at all.

The ancient Chinese yin-yang figure symbolizes the fundamental harmony of opposites. The dark part (the yin) symbolizes the feminine, dark, receptive, "negative" aspects; and the light part (the yang), the masculine, light, aggressive, "positive" aspects. The yin-yang figure indicates that the yin and yang aspects are absolutely dependent on each other: without dark there is no light, without light there is no dark. The dark dot in the light part, and the light dot in the dark part indicate that nothing is completely yin and nothing completely yang. The traditional Chinese approach to healing and life in general is to act to maintain the balance between yin and yang. By contrast, the typical "Western" approach is to attempt to ensure the "victory" of the "positive" over the "negative".

Most people are aware of the risk of surgery, sometimes to such an extent that they choose not to have something done that would probably help them. Most are aware of the problems associated with pills and injections. Few people, including doctors, however, recognize the propensity of little eye drops to cause big problems. If the patient were aware that the one eye drop she was using each day might be the reason why she was falling asleep every time she sat down, or why she had unexplained painful bowel spasms, attention could be properly directed to the cause.

At that point, the patient might decide to bear with the fatigue or the bowel spasms as a tolerable cost for the preservation of vision. But at least both the doctor and the patient would understand the cause for the fatigue or the bowel spasms, eliminating the need for other diagnostic tests and potentially even more damaging treatment.

Patients will sometimes ask what sort of side effect they should watch for. Different classes or families of drugs do tend to have similar clustering of side effects. But each individual is a unique person and reacts uniquely to every drug. Thus, though it is helpful to know that the beta-blockers tend to be "downers," slowing the heart, making people fatigued, making them think less well and lowering their blood pressure, occasional people will have very different effects from beta-blockers, for example, high blood pressure.

Eye Drops and the Doctor - Patient Relationship

While the doctor should be aware of the types of side effects associated with a particular medication, almost any problem could be caused by one of the medications someone is taking. Especially if some type of symptom develops shortly after a new medication is started, it makes sense to attribute the symptom to the medication.

As hinted earlier, it's not just the serious side effects that are the problem. Of course, it's a real concern if a person develops a terrible rash over his whole body, or loses control of his/her bladder. But people notice such obvious problems and usually bring them to the attention of their physician. The less obvious problems are common, and are of real concern, because they are routinely overlooked. For example, in answer to a question such as "Are you feeling fatigued," it is common to get the answer something like, "Yes, but then I'm getting older." Or, in response to the comment, "It looks as though you've been losing weight," the patient will frequently say, "Yes, but you know I live alone and I haven't been cooking for myself well." These may be minor difficulties at the start, but they often turn into major concerns if not recognized.

Appropriate risk-taking is an essential part of a mature, healthy, joyful, productive life. People who are considered "competent" by the legal system have the right to make decisions that affect their well-being. The principle of "informed consent" is one of the ways our society protects people from having others inappropriately make decisions for them. One of the physician's appropriate responsibilities is providing enough information to a competent person to allow that person to make a decision in his or her best interest. Physicians, like everybody else, tend to focus on that segment of life with which they are most familiar and most concerned. Ophthalmologists know about the eyes and what damages the eyes, and have as a top priority preservation of the health of the eyes and of vision. The individual patient is appropriately focused on what he or she considers best for himself or herself. The individual's goals and priorities may differ from those attempting to advise or help the individual, even when the helper is sincere. Thus, the individual patient should become knowledgeable and should take appropriate control over decisions that affect his or her well-being.

Getting the Best Results

The use of any eye drop is going to introduce some side effect. The side effect may be as minimal as temporary blurring of vision, or as maximal as causing the person's death. Because each individual person reacts uniquely, it is impossible for the physician to predict accurately how any individual person will react to a medication. The conclusion might then be that it is, therefore, impossible for a physician to give the patient adequate information to make appropriate the decisions.

But there is a solution to this apparent dilemma. The physician can help patients understand their uniqueness, and their right and their need to make decisions themselves. Because side effects cannot be accurately predicted, it is essential that the patient know that side effects cannot be accurately predicted, and for the patient to be alert to the possibility of all sorts of side effects and to pass concerns on to the physician, so that there can be a discussion of whether it is likely it is that the medication is causing the concern, and what would be the next appropriate steps to get the information necessary to permit an informed decision about what to do next: Should the medication be discontinued; should it be modified; should a new medication be substituted; should it be continued; what are the risks of stopping the medication; what are the potential benefits of stopping the medication, etc.

There are now many highly effective medicines to use for the treatment of glaucoma. For some patients, it is appropriate and in their best interest to be treated with medicines; for some patients, medicines need to be combined with other treatments. For yet other patients, the treatment of their glaucoma is best accomplished without medications, either because other approaches are more likely to be successful, or because the side effects caused by the medicines are not warranted in view of the potential benefits.

In every situation, the most appropriate decision is worked out by an open, honest, and ongoing communication between the doctor and the patient.