Surgeon: Glaucoma most challenging discipline of the 21st century

Addressing acute closed-angle glaucoma may be most important in some Asian countries for preventing glaucoma-related blindness.

Glaucoma, in all its forms, will be a major clinical challenge for ophthalmologists in the 21st century, according to a leading surgeon in Southeast Asia.

The problem of glaucoma is global, said Prof. Arthur S.M. Lim, MD (Hon), FRCS, but it manifests differently in different areas of the world.

In an interview with Ocular Surgery News, Prof. Lim described the difficulties facing ophthalmologists in managing glaucoma as a cause of vision impairment and blindness worldwide.

Prof. Lim said glaucoma is emerging as the most difficult medical discipline of the 21st century.

As if to second Prof. Lim's concerns, shortly after our interview with him, the World Health Organization announced that glaucoma is now the second leading cause of blindness in the world, second only to cataract.

Prof. Lim is a member of the Editorial Board of Ocular Surgery News Europe/Asia-Pacific Edition.

Ocular Surgery News: Why do you think glaucoma is the most challenging discipline of the 21st century?

Prof. Arthur S.M. Lim, MD (Hon), FRCS: There are several reasons. First, the problem is global. Second, epidemiologic studies have shown that the condition manifests differently among different nations and different ethnicities. Third, it is a major cause of blindness and in some cases is preventable. Fourth, as it is age-related, it is on the increase with our aging population.

As glaucoma is clinically common, it has become important in clinical practice. Every eye doctor has a role in the proper management of glaucoma and prevention of blindness for glaucoma patients. In addition, failure to diagnose and to treat glaucoma adequately can lead to serious medicolegal actions.

OSN: What are the main problems facing ophthalmologists in treating glaucoma?

Prof. Lim: The acceptable target for IOP has changed. It was for many years 21 mm Hg. Now the current recommendation is that the level of target pressure be related to the severity of glaucoma. The more damage to the optic nerve, the lower the pressure.

Additionally, there is a need to protect the optic nerve, but neuroprotective eye drops are not yet available.

Another challenge is that the condition is different among different races. For example, acute angle-closure glaucoma is more severe in the Chinese, and the condition is much more common among the Chinese than in whites.

There is disagreement regarding the best eye drop for reducing IOP. The newer drops, which are more effective, are also more costly. The question is, can we manage glaucoma without the new, costly medications? Similarly, there are so many new and expensive diagnostic technologies. Can we manage glaucoma without these newer diagnostic devices?

Source: Lim ASM

The concept of priority in drug regimens has become a major debate. Even in Singapore — a first-world country — there are limitations on the use of Xalatan (latanoprost, Pfizer) in public hospitals. Is that decision correct? There is no way poorer, developing countries can afford the new, more costly medications and technologies. What then should the recommendation be?

It is obvious that guidelines for glaucoma treatment in the United States must be different from those in developing nations. All this has led to debate and challenges. Leading international ophthalmologists must have a clear understanding of the racial and ethnic differences and the cost of appropriate treatment in the management of glaucoma in different countries.

OSN: How are different regions affected by the different forms of glaucoma?

Prof. Lim: There are two main types of glaucoma — closed-angle glaucoma and open-angle glaucoma. Closed-angle glaucoma is more common in Asia and among the Chinese.

Both forms of glaucoma cause blindness. However, the degree of blindness varies among countries depending on how common the form of glaucoma is. The world's figures indicate that approximately 60 million people suffer from glaucoma. Of these people, approximately 10% are blind. Of those who are blind, approximately half are blind from open-angle glaucoma and the other half from closed-angle glaucoma.

Of those who are blind from closed-angle glaucoma, half presented initially as acute glaucoma. Acute glaucoma is particularly important in China, Taiwan and Southeast Asian countries — especially among their Chinese populations. Blindness in these cases can be prevented.

An interesting finding is that closed-angle glaucoma is not common among the Japanese people. Rather, normal-tension glaucoma of the open-angle type is more common in the Japanese. Many reasons have been suggested why this should be so. Is it because many Japanese people are myopic? Is it because cataract surgery is performed more often? Is it because the Japanese ophthalmologists more frequently use more technologically sophisticated machines and therefore diagnose normal-tension glaucoma more readily?

In Europe, open-angle glaucoma is three to ten times more common than closed-angle glaucoma. The problem there is the early diagnosis of open-angle glaucoma. Screening programs have been suggested, but these are costly and their cost effectiveness is uncertain.

Another problem is that new diagnostic methods and newer drugs are costly. Which drug is the drug of choice? Which drug should patients start off with? And there is debate on the use of trabeculectomy, modifications to the procedure and the use of plastic tubes in advanced glaucomas and cases not responding to treatment.

OSN: What form of glaucoma presents the greatest challenge?

Prof. Lim: That depends on the country. In my opinion, the management of acute closed-angle glaucoma presents the greatest challenge, and the reason is that blindness or severe visual loss from acute glaucoma can be prevented. Prevention depends not only on early diagnosis and treatment by eye surgeons, but the participation of all eye care providers, general practitioners, opticians, nurses and also the public.

Acute glaucoma has multiple symptoms. Patients therefore seek care. Everyone should be told that in a middle-aged person with acute pain, with headaches on one side associated with blurred vision and a red eye, a diagnosis of acute glaucoma should be considered until it is proven otherwise.

In these patients it is also important that the fellow eye be treated because laser iridotomy will prevent acute glaucoma from developing in the fellow eye. Thus blindness in the "normal" fellow eye can always be prevented.

All these factors, in my opinion, have made acute closed-angle glaucoma more challenging than other forms of glaucoma.

OSN: Why should the focus be on acute closed-angle glaucoma as opposed to other forms of glaucoma?

Prof. Lim: The main problem with glaucoma is its early diagnosis. In primary open-angle glaucoma, which is silent and is known as the “thief of sight,” the patient is not aware of damage to his or her vision and optic nerve. The damage is usually discovered only when severe visual loss has developed. There are problems with screening, which is costly and has become controversial, although important. Because of this, despite newer methods of diagnosis and newer glaucoma eye drops, chronic open-angle glaucoma, I believe, will continue to blind thousands of patients each year. The situation is the same with chronic closed-angle glaucoma. As we know, the clinical presentation of chronic closed-angle glaucoma is similar to that of open-angle glaucoma.

In contrast, with acute glaucoma, the patient seeks medical care because the eye is blind, the patient has pain and the eye is red. The need for screening is not there because the patient seeks care. That is an advantage in detecting acute glaucoma — provided the diagnosis is made early and treatment is provided adequately and quickly. If given quickly, normal vision can be restored and the fellow eye, with laser iridotomy, will not be blind.

It is a shame that many working in the prevention of blindness, specifically those in the prevention of blindness from glaucoma, fail to realize this. It is unfortunate that the 1999 report from the Prevention of Blindness meeting in Beijing did not mention acute glaucoma. In my opinion, the most important step that the World Health Organization, the International Agency for the Prevention of Blindness, other international and national organizations, and ophthalmologists can take is in the prevention of blindness from acute glaucoma in the 21st century.

OSN: What do you see happening with glaucoma in the future?

Prof. Lim: I see increasing blindness globally from glaucoma. We cannot avoid this because the world's population is getting older. But I believe a global action to prevent blindness from acute glaucoma will develop despite relative indifference today. The press will have an important role in persuading world leaders. I believe that in 5 years blindness from acute glaucoma will fall dramatically.

In chronic glaucoma, it will depend on drugs, which hopefully will become less expensive, and on new surgical procedures that may be more effective than trabeculectomy or its variations. But until those things come, my prediction is that in 5 to 10 years, blindness from glaucoma will still be increasing.

Indeed, experienced clinicians are important in the management of complex glaucoma, and they should balance enthusiasm for short-term procedures and technology with considerations for long-term management. As David L. Epstein, MD, has stated, “The fields of glaucoma are littered with relics of short-term enthusiasm for certain procedures and techniques.”

Of all the fascinating challenges we will confront in the 21st century, glaucoma promises to be the most intriguing. Young ophthalmologists will find themselves drawn to the study, management and surgery of glaucoma. As glaucoma is not only an affliction of individuals but also a leading cause of world blindness, they will find themselves embarking on an exciting and profitable odyssey of global significance.

For Your Information:

• Prof. Arthur S.M. Lim, MD (Hon), FRCS, can be reached at the National University of Singapore, Department of Ophthalmology, Lower Kent Ridge Road, Singapore 119260; +65-6772-5318; fax: +65-6777-7161; e-mail: eye.clinic@pacific.net.sg.

• Michael Piechocki, who conducted this interview, is an OSN Correspondent who writes principally for OSN’s sister publication Orthopedics Today.