World blindness: The cost of a child’s eyes

First in a series discussing the major causes of world blindness and the specific challenges and possible strategies for dealing with each.

Issue: August 1, 2006

ByNathan G. Congdon, MD, MPH

A note from the editor:
One of my objectives in taking on the role of Glaucoma Section Editor for OSN was to increase awareness of some of the vexing issues pertaining to international ophthalmology in general and, more specifically, blindness from glaucoma in developing countries. I was very pleased to successfully recruit Nathan G. Congdon, MD, MPH, to serve as a Glaucoma Section Member and to take on the lead role in addressing some of the issues related to global blindness.

This is the third such article dedicated to global blindness, and how international volunteerism can make a difference. In the January 15 issue of OSN (page 13), Richard A. Lewis, MD, described a mission he went to in Libya with Project Orbis. In the May 1 issue, Richard P. Wilson, MD, described his experiences while on a surgical expedition in Kenya. Their stories provided compelling testimony that individuals can make a difference in saving sight.

In this issue, Dr. Congdon discusses the issue of childhood blindness. Some of the figures, such as the markedly reduced life expectancy of a blind child, are truly haunting. It is our hope that Dr. Congdon’s unique expertise in this profoundly important topic will serve as a call to arms for many of us to either contribute monetarily or with our time and talent toward elevating the quality of eye care in some of the more underserved areas of the world.

Thomas W. Samuelson, MD
OSN Glaucoma Section Editor

Nathan G. Congdon

When we think of blindness prevention in an international context, there is often a tendency to focus on cataract surgery. There are good reasons for this: Cataract remains the leading cause of world blindness, and its surgical alleviation is widely known as one of the more cost-effective interventions in health care. In India, for example, it has been estimated that the cumulative economic loss due to blindness is US$77.4 billion, while the total cost to eliminate blinding cataract would be only US$150 million.

Global Vision 2020, a campaign coordinated between the World Health Organization and various vision-related non-governmental organizations (NGOs) with the goal of eliminating preventable blindness by 2020, has brought other important causes of blindness onto the world stage, including childhood blindness, trachoma and onchocerciasis. An integrated approach to blindness is far more efficient than implementing vertical programs, which may cure one man’s cataract while ignoring the glaucoma or refractive error affecting his neighbor or family members. The next few columns in this series will consider these other important causes of blindness (with cataract getting its turn, as well), attempting to point out the specific challenges and possible strategies for dealing with each.

The impact and importance of childhood blindness has been underestimated for many years and for a variety of reasons, the most obvious of which is a simple but tragic fact: Blind children die, as many as 60% of them within a year of losing their vision. Any effort to count surviving blind children as an index of the impact of pediatric vision loss will inevitably reach only the tip of the iceberg. While many of the causes of childhood blindness are rare compared to age-related blinding disease, such as cataract and glaucoma, the number of children who lose their vision each year, estimated at half a million worldwide, is not small.

Losing a lifetime of vision

The impact of this loss is greatly magnified by the fact that a blind child loses a lifetime of vision. Estimating this conservatively at 50 years, it is not difficult to see how the impact of 500,000 children going blind each year might soon rival that of the 4 million to 5 million adults estimated to lose vision from cataract annually. In fact, of the U.S. $77.4 billion estimate mentioned for economic loss due to blindness in India, nearly one-third is due to blindness in children.

An example of the importance of childhood blindness that is somewhat closer to home may be found in Brown’s recent cost-effectiveness figures for different ophthalmic procedures in the United States. At the top of the list as the most cost-effective intervention in ophthalmology was laser treatment for retinopathy of prematurity, due to the many potential years of vision saved.

Nearly three-quarters of these children live in the developing world, and it is estimated that half of all childhood blindness is preventable. The causes of pediatric vision loss are various, and specific prevention strategies will be discussed in later articles covering specific conditions. Some of the unique challenges facing childhood blindness programs are best illustrated by considering specific diseases. Conditions such as pediatric cataract and glaucoma are comparatively rare, making screening challenging. Their surgical remediation requires not only specialized training, but also pediatric anesthesiologists and facilities.

Follow-up needed

Good results cannot be achieved for these conditions without careful and persistent follow-up. This is expensive and difficult to provide, particularly when children may reside at a distance from the tertiary facilities where such procedures are most frequently performed. Pediatric corneal blindness from causes such as vitamin A deficiency is an even more challenging problem. Although the causes are frequently avoidable, once the condition itself is present, surgical treatment is extraordinarily difficult, due to the low success rate and intensive follow-up required for pediatric corneal grafts.

Amblyopia is another cause of pediatric vision loss for which follow-up is critical for success and may frequently be poor. Studies in Baltimore have found that only one-third of children followed up as directed for treatment of their amblyopia. Retinopathy of prematurity, a condition of growing importance in Latin America, India and Southeast Asia, further illustrates the potential technical difficulty of diagnosing and treating pediatric vision problems. The ability to visualize the peripheral fundus and to recognize threshold disease may require training well beyond what the average ophthalmologist receives in Asia or Latin America.

The problem of ophthalmia neonatorum highlights another type of challenge in pediatric blindness prevention: The problem can be avoided with prophylactic therapy at birth. However, treatment of newborns in areas where deliveries frequently do not occur in central facilities will require significant outreach efforts through groups such as traditional birth attendants.

Refractive correction

Refractive error is an important cause of low vision in children and is responsible for as much as 95% of decreased vision among children in China, and 50% to 75% in Chile and Australia. Much refractive error in children goes uncorrected — more than 90% in rural China 50% in Chile and 25% even in Australia. Recent studies have shown that even when children are provided spectacles at no cost, a high proportion may not wear them, often due to concerns over their appearance. Refractive and visual cutoffs for the provision of spectacles to children have not been well validated. Perhaps most important, the impact of refractive correction on children’s school performance and other “real-world” outcomes has yet to be demonstrated. Programs in pediatric refractive error must find better ways to deliver spectacles to the children who most need them, while making certain that these spectacles continue to be used.

Few doubt the importance of childhood blindness, even compared to more common adult vision problems, given the impact of a lifetime of vision lost and frequently the loss of an actual life whenever a child goes blind. The challenge facing those of us who would reduce or eliminate the global burden of childhood blindness is to find sustainable ways to pay for case detection, equipment, training and follow-up for blinding childhood disease. One key approach may be to position childhood vision interventions strategically as a part of integrated eye health programs, thus allowing potentially more profitable activities such as cataract surgery to cross-subsidize children’s services. Greater efficiencies may also be achieved by integrating pediatric eye health into broader children’s health care or educational initiatives. While the costs and technical challenges of childhood blindness prevention may be many times those of adult vision programs on a per case basis, the benefits, too, may be equally large.

See the September 1 issue, where Dr. Congdon will discuss a global approach to glaucoma treatment.

For more information

Nathan G. Congdon, MD, MPH, is Director of Eye Health at Hellen Keller International. He can be reached at ncongdon1@gmail.com.

For information on volunteering overseas, contact the American Academy of Ophthalmology's International Public Service section at 415-447-0281.

Thinking Globally Column Mission Statement: To address the challenges facing efforts to reduce the global burden of preventable blindness, and consider the strategies, diseases and collaborations, which together define the fight for sight.

Reference:

Brown MM, Brown GC. How to interpret a healthcare economic analysis. Curr Opin Ophthalmol. 2005; 16:191-194.