Aging population contributes to rising glaucoma burden around the world

Reducing the occurrence of glaucoma poses a challenge around the world, with nearly 8 million people bilaterally blind from the disease. That number is estimated to increase over the next 10 years as the population ages.

“The actual prevalence of the disease is rising not because the incidence is rising, but because the population at risk is increasing,” Harry A. Quigley, MD, of Wilmer Eye Institute at Johns Hopkins University, said. “For example, in China, the proportion of people who are of the age to get glaucoma is expanding dramatically. In India, in South Asia, it’s expanding dramatically. People are living longer. It isn’t that the disease is becoming more common, it’s that the people who get it are becoming more common.”

Glaucoma is the No. 2 cause of blindness in the world, behind only cataracts. However, glaucoma is the leading cause of irreversible blindness. An estimated 8.4 million people worldwide will be bilaterally blind from glaucoma in 2010. By 2020, that number is estimated to rise to 11.1 million.

The key to preventing blindness from glaucoma is effective diagnosis and treatment for at-risk patients in developed and developing countries. But treating the disease is a challenge in some areas, including China, India and Africa, where patients are often undiagnosed or do not have access to care or affordable care.

A total of 60.5 million people worldwide will have open-angle glaucoma and angle-closure glaucoma in 2010, and by 2020, an estimated 79.6 million people will have the disease, Dr. Quigley and Aimee T. Broman, MA, found in a study published in the British Journal of Ophthalmology in 2006.

Harry A. Quigley, MD, of the Wilmer Eye Institute at Johns Hopkins University, attributes the rise in glaucoma prevalence to the increased number of at-risk patients. Image: McElwaine M

In 2010, China is expected to have the highest number of patients with open-angle glaucoma and angle-closure glaucoma, followed by Europe and India, Dr. Quigley and Ms. Broman found. Africa will have the highest ratio of glaucoma-to-adult population. India will have the most detectable change in increase of the disease worldwide and will surpass Europe in 2020 in number of cases, the researchers estimated.

About 2.2 million Americans 40 years and older have glaucoma, according to an estimate by Friedman and colleagues in 2004. By 2010, about 2.79 million people in the U.S. will likely have open-angle glaucoma, Dr. Quigley and Ms. Broman found.

In the U.S. and other developed countries, rates of glaucoma are rising as the population ages. In the next 25 years, the American population older than 65 years is expected to double to 72 million people. Because the fastest growing population in developed countries is people older than 80 years, and because age is a major risk factor for the disease, the rate of glaucoma will continue to increase in the next 20 years, Ivan Goldberg, MBBS, FRANZCO, FRACS, a clinical associate professor at the University of Sydney, Australia, said.

Ivan Goldberg

“You’ve got a disease that is exponentially increasing in its prevalence with increasing age, and you’ve got an exponentially increasing graying of the population,” Dr. Goldberg said. “You put the two curves together, you realize that glaucoma is becoming an ever-increasing challenge.”

Around the world, the burden of glaucoma affects daily lives, Rupert Bourne, BSc, FRCOphth, MD, said.

“In day-to-day life, suffering from glaucoma has a major impact on one’s ability to function,” Dr. Bourne, who co-directs the Vision and Eye Research Unit in Cambridge, England, said. “There are an enormous number of people with it. It has a significant impact on quality of life even when of moderate severity, and its irreversibility makes this a major public health problem.”

Financial cost in developed countries

Glaucoma is an expensive disease to treat, and the recent economic downtown has rendered affordability of care in developed countries increasingly difficult.

According to Dr. Quigley, patients in many European countries benefit from national health care systems that help regulate the cost of treating the disease. However, for patients on multiple medications in the U.S., the out-of-pocket price of medical therapy can be substantial. A total of $2.86 billion is spent annually in the U.S. on glaucoma patients 40 years and older in direct medical costs, representing outpatient, inpatient and prescription drug costs, Rein and colleagues found.

Cost of care for glaucoma is also expensive, Dr. Quigley said. Office visits for glaucoma-related care are the third most frequent reason across all fields of medicine why patients see physicians in the U.S., behind visits for hypertension and diabetes care, he said.

“Since Medicare is now, partly, to some degree covering pharmaceuticals, the visit charge, surgery charges and pharmaceutical charges are huge ticket items under Medicare,” Dr. Quigley said. “I think it won’t take terribly long, if they actually do get serious about reforming health care, before the government in the U.S. looks at that issue and figures out a more efficient way to take care of glaucoma than we’re now doing.”

Nathan G. Congdon, MD, MPH, said other costs that can become expensive over time might be overlooked, including transportation for patients to go to office visits and diminished productivity caused by visual loss.

Nathan G. Congdon

“There are … burdens of treatment, particularly in the United States and Europe and the developed countries, where the government does pay a substantial part of the treatment,” he said. “[Glaucoma is] one of the more common conditions that we treat among older people, not just the cost of medicines, but the cost of office visits, the cost of various tests that need to be done in order to treat the disease. Those are part of a substantial cost that adds up as well.”

Financial cost in developing countries

In the developing world, cost of treatment has been an acute problem, Dr. Congdon said. He is a professor at the School of Public Health, Chinese University, Hong Kong, and has worked extensively in rural China through the Joint Shantou International Eye Center, Shantou, China. With nearly 70% of China’s population living in rural areas, health care access in those regions is vital to glaucoma diagnosis and treatment.

Beginning in 1978 in China, at the time of Deng Xiaoping’s economic reforms, the Chinese government withdrew its support for health care, and the old rural insurance system, the Cooperative Medical System, collapsed as a result, according to Dr. Congdon. Health care became inaccessible and unaffordable to most rural residents; the gaps between rural and urban citizens in blindness rates, life expectancy and infant mortality grew as a result.

The situation has improved in recent years, since the New Cooperative Medical System was established in China, bringing affordable care to more than 95% of rural residents, he said. Patients pay the equivalent of $3 a year to have 40% to 70% of their health care covered by the government.

But there is still a lack of physician training and skill in rural areas that needs to be addressed, he noted.

In Africa, the problem of affordability and access to care is evident from the rising rate of adults who have glaucoma damage. In Ghana, studies have shown that the rate of open-angle glaucoma is high and comparable to rates in black populations in Barbados and St. Lucia. Leon W. Herndon, MD, of Duke University Medical Center, travels regularly to Ghana to perform glaucoma surgery, deliver care and research the disease.

Leon W. Herndon

The biggest difficulties for glaucoma patients in obtaining adequate eye care in Ghana are infrastructure and the lack of ophthalmologists and services, he said. Ghana has only about 40 ophthalmologists for a population of approximately 20 million people. Ophthalmologists there are trained in cataract surgery, but not as much in the surgical management of glaucoma, he said.

In addition, glaucoma medication is often unavailable or too expensive, and glaucoma surgery is sometimes ineffective, with visual loss after surgery.

“The problem with glaucoma is not necessarily the surgery — that’s fairly straightforward in most cases — but the follow-up,” Dr. Herndon said. “I think it’s important that we emphasize in developing countries that glaucoma is often a surgical disease, for the very reason that you bring in [drug] samples, samples run out, and what do you have left? We definitely need to focus on the improvement of surgical outcomes of glaucoma surgery in West Africa.”

Quality of life

Not only do individuals and governments incur costs in the treatment and care of glaucoma patients, but there is also a quality-of-life cost for those with the disease.

Dr. Bourne is coordinating the vision loss group for the Global Burden of Diseases, Injuries, and Risk Factors project, which will report in 2010 on the contribution of glaucoma to the global burden of disease by reviewing all population-based studies for the past 30 years. He said that limited research has been conducted comparing the effect on quality of life of visual loss or blindness caused by glaucoma as compared with other ocular diseases, such as age-related macular degeneration.

“Although we know as clinicians that there are differences, very few studies have tried to evaluate it,” he said. “The diseases typically affect different areas of the visual field. Glaucoma blindness is far more problematic than the central visual loss associated with age-related macular degeneration in terms of function.”

Dr. Quigley is studying quality-of-life issues in U.S. patients with moderate glaucoma. For the older population, visual loss from glaucoma can be devastating because patients can lose their independence when vision loss prevents them from driving. Patients who cannot drive sometimes have no other option than to leave their homes and move into assisted living facilities, he said.

Loss of vision from glaucoma also becomes a burden when patients attempt to do basic tasks such as reading, he said. In addition, GPS monitoring devices on patients’ belt buckles have shown how physical activity is affected by vision loss from the disease.

“It changes a lot of things that people enjoy in their lives to have a blinding condition like glaucoma, even when it doesn’t put them in the state of being so-called legally blind,” Dr. Quigley said.

Awareness of the disease

One of the major impediments to adequate diagnosis and treatment of the disease is lack of awareness of the disease. In urban India, the awareness rate of glaucoma is 13.3% and knowledge of the disease is 8.7%, according to Lingam Vijaya, MBBS, MS, director of Glaucoma Services, Sankara Nethralaya, Chennai, India.

Lingam Vijaya

“These rates were significantly lower as compared to awareness among other developed countries,” she said. “These factors would lead to late presentation of patients with the disease, thus having a more severe form of disease.”

Rates for awareness of the disease in rural India are even lower, according to the Andhra Pradesh Eye Disease Study. The survey found that less than 1% of the rural population interviewed in India knew about the disease.

An estimated 90% of glaucoma cases in urban and rural India are undiagnosed, Dr. Vijaya said.

In developed countries, the rate of individuals who are unaware that they have glaucoma is lower than in India, but still high: An estimated 50% of those in the U.K. with the disease do not know they have it, Dr. Bourne said.

Detection of glaucoma in the U.K. is mainly a result of opportunistic screening by optometrists, which addresses only a small unrepresentative portion of the population. Dr. Bourne’s team is investigating how detection rates and sensitivity and specificity of detection can be improved by working with optometrists in community-based settings.

Research by his team in the Pakistan National Blindness and Visual Impairment Survey, which surveyed 16,500 adults, showed that only one-third of glaucoma cases had previously been diagnosed, and one-quarter of the cases detected by the survey were blind. Improved awareness of the disease by primary health care workers in this setting may increase the detection rate.

Improving awareness

Dr. Vijaya said people around the world need to know that they should have regular eye exams to assess glaucoma risk.

“Increasing awareness about glaucoma will increase case detection and thereby reduce blindness due to glaucoma,” she said. “The cataract surgical program in [India] targets the same age group of patients who are at risk for glaucoma and has reasonably good coverage in rural India, too. Ensuring that even a significant percentage of those who are examined as part of a cataract surgical initiative are evaluated for glaucoma would improve detection rates significantly.”

Many organizations, initiatives and programs are working to educate and bring awareness about the disease to individuals and governments around the world. World Glaucoma Day, which was started in 2008, brings awareness of the disease to a worldwide audience. Co-sponsored by the World Glaucoma Association and the World Glaucoma Patient Association, the day was partly modeled on National Glaucoma Week in Australia, held by the nonprofit organization Glaucoma Australia for the last 20 years.

Beverley Lindsell, vice president of the World Glaucoma Patient Association and national executive officer of Glaucoma Australia, said she hopes the organization’s work will help increase knowledge of the disease in local communities.

“One day, it is my hope that everyone will know what glaucoma is, that they can pronounce the name correctly because they have heard it so many times that it has become a household word,” she said. “It is through the work of all the existing patient associations and events such as World Glaucoma Day that we look forward to stemming the tide of this eye condition.”

In 2010, World Glaucoma Day will be expanded to World Glaucoma Week and will be held March 7 to March 13, according to Ms. Lindsell.

Another program, the All Eyes on Glaucoma campaign, is looking to educate the public and press about risk factors for the disease, Dr. Goldberg said. Sponsored by Pfizer, the campaign emphasizes the need for early diagnosis, especially in at-risk individuals.

“All Eyes on Glaucoma is a global program to try to increase community awareness of the disease, particularly amongst eye care workers, all of which is attempting to increase the diagnosis rate, so that more of the undiagnosed people can be identified and offered treatment,” Dr. Goldberg said.

The World Glaucoma Congress has also been working on education and awareness outreach, particularly in West African countries. The group is looking to establish seminars about basic glaucoma knowledge for ophthalmologists in sub-Saharan Africa.

Vision 2020, a joint program of the World Health Organization and the International Agency for the Prevention of Blindness, considers glaucoma one of its priority eye diseases in its mission to eliminate avoidable blindness.

The International Glaucoma Association is another group working to bring awareness of the disease to the public, according to David J. Wright, chief executive of the association. The patient-based charity organization is based in England.

“It … raises public awareness of the condition and the need for regular routine, comprehensive eye testing in order to encourage the early detection of the condition, and it funds considerable research into various aspects of glaucoma,” he said.

Possible solutions

One important way of reducing burden of disease is the development of new and safer surgical options. More research into affordable medical therapy options that do not require as much patient adherence is also needed and could be an additional solution.

“I think that in the next 20 years it’s very likely … that we will develop more effective surgical treatment,” Dr. Quigley said. “We will develop more effective ways of delivering medicine to lower the eye pressure that don’t depend on daily eye drop therapy, which would improve dramatically the adherence to therapy.”

Another potential way to reduce the worldwide glaucoma burden is the creation of effective screening techniques. These screenings could help prevent glaucoma damage through early identification of those with the disease. Awareness of the need for glaucoma screening for those at highest risk for the disease is also vital around the world.

Finally, physicians should be aware that the aging world population is one of the leading reasons for the increasing rates of glaucoma, Dr. Quigley said. They should focus on diagnosing and treating at-risk patients.

“Our job is to find those that are more rapidly changing and be very aggressive about treating them,” he said. “Right now, that means lowering their eye pressure and not doing aggressive things that are damaging to persons who are not rapidly progressing, so we don’t compound their glaucoma by causing them to have other problems, like cataract or complications of eye surgery for glaucoma.” – by Erin L. Boyle

What is one cost-effective way of reducing visual loss from glaucoma in aging populations around the world?

References:

• Bourne RR. Worldwide glaucoma through the looking glass. Br J Ophthalmol. 2006;90(3):253-254.
• Friedman DS, Wolfs RC, O’Colmain BJ, et al; Eye Diseases Prevalence Research Group. Prevalence of open-angle glaucoma among adults in the United States. Arch Ophthalmol. 2004;122(4):532-538.
• George R, Vijaya L. First World Glaucoma day, March 6, 2008: Tackling glaucoma challenges in India. Indian J Ophthalmol. 2008;56(2):97-98.
• Ntim-Amponsah CT, Amoaku WMK, Ofosu-Amaah S, et al. Prevalence of glaucoma in an African population. Eye. 2004;18(5):491-497.
• Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006;90(3):262-267.
• Rein DB, Zhang P, Wirth KE, Lee PP, Hoerger TJ McCall N, et al. The economic burden of major adult visual disorders in the United States. Arch Ophthalmol. 2006;124(12):1754-1760.
• Rodriguez J, Sanchez R, Munoz B, et al. Causes of blindness and visual impairment in a population-based sample of U.S. Hispanics. Ophthalmology. 2002;109(4):737-743.

• Rupert Bourne, BSc, FRCOphth, MD, can be reached at The Vision and Eye Research Unit, Postgraduate Medical Institute, Anglia Ruskin University, Cambridge, England CB1 1PT; e-mail: rb@rupertbourne.co.uk.
• Nathan G. Congdon, MD, MPH, can be reached at the Department of Ophthalmology and Visual Sciences, Chinese University of Hong Kong; e-mail: ncongdon1@gmail.com.
• Ivan Goldberg, MBBS, FRANZCO, FRACS, can be reached at 187 Macquarie St. Park House, Floor 4, Suite 2, Sydney NSW 2000, Australia; 61-2-9247-9972; fax: 61-2-9232-3086; e-mail: eyegoldberg@gmail.com.
• Leon W. Herndon, MD, can be reached at Duke University Medical Center – Ophthalmology, Box 3802, Durham, NC 27710; 919-684-6622; fax: 919-681-8267; e-mail: hernd012@mc.duke.edu.
• Beverley Lindsell can be reached at P.O. Box 420, Crows Nest NSW Australia 1585; 61-2-9906-6640; e-mail: lindsell@glaucoma.org.au.
• Harry A. Quigley, MD, can be reached at Wilmer Eye Institute, Johns Hopkins University, 600 N. Wolfe St., Wilmer 120, Baltimore, MD, 21287; 410-955-6052; fax: 410-955-2542; e-mail: hquigley@jhmi.edu.
• Lingam Vijaya, MBBS, MS, can be reached at Sankara Nethralaya No. 18, College Road, Nungambakkam, Chennai - 600 006, Tamil Nadu, India; 44-2827-1616; e-mail: drlv@snmail.org.
• David J. Wright can be reached at Woodcote House, 15 Highpoint Business Village, Henwood, Ashford, Kent, TN24 8DH, England; 44-01233-648170; fax: 44-01233-648178; e-mail: d.wright@iga.org.uk.