Challenges of worldwide vision loss great, but potential benefits of treatment greater
The recently published WHO World Report on Vision is required reading for anyone interested in reducing the burden of vision impairment in the world, whether government agency, nongovernment agency, eye care provider, member of industry, investor or philanthropist.
According to this report, 2.2 billion of the approximately 7.7 billion people in the world suffer from one or another visual impairment. That is about 28% of the world population, or just more than one in four people. Most of us in advanced countries would suspect the primary causes of visual impairment to be cataract, glaucoma and retinal disease. Wrong: The No. 1 cause of visual impairment in the world is uncorrected refractive error. Worldwide, there are 2.6 billion people with myopia, and as we have discussed in recent OSN articles, progressive myopia is now epidemic and in great need of safe and effective treatments. In many parts of the world, contact lenses are an impossible dream, and even glasses are not readily available.
More than 30 years ago, I was invited by the U.S. Public Health Service to travel to Alaska to help train ophthalmologists in corneal refractive surgery. The target patient was the indigenous Eskimo who lived in the tundra and survived by hunting and fishing. Myopia was, for many, a potential death sentence, with glasses being woefully ineffective in a very extreme climate and contact lenses impossible. Corneal refractive surgery was the best option and highly effective. While most of us think of refractive surgery as a lifestyle enhancement for the affluent few, if delivered in a cost-effective, efficient way, it could be far superior to glasses or contact lenses in enhancing a visually impaired individual’s function in many highly challenging and rural environments.
Even more unexpectedly, as life expectancy advances, uncorrected presbyopia has become a major cause of visual impairment globally. There are 1.8 billion presbyopes in the world, and without reading glasses, they are handicapped by a meaningful visual impairment as near vision has become ever more critical to our daily lives. Here, in my opinion, the pharmacologic treatment of presbyopia might deliver a dramatic benefit. Again, while many of us in the U.S. might consider an eye drop that enhances near vision a luxury to be enjoyed on an evening date to reduce dependence on reading glasses, in some parts of the world it could well prove to be the best way to overcome the visual impairment associated with presbyopia, allowing near tasks required for survival, such as cooking, sewing, building and mechanical repairs to be completed by those older than age 45 years.
Of course, astigmatism and hyperopia deserve therapy as well, but myopia and presbyopia are the big two, and corneal refractive surgery and pharmacologic refractive treatment may well prove superior to glasses or contact lenses for millions.
Next comes the expected pathologies that predominate in the advanced countries. While just more than 26 million cataract surgeries are performed every year in the world, at least 65.2 million who would benefit from cataract surgery are untreated. If the eight or so per thousand population cataract surgeries done per year in Europe are the correct goal, for the 7.7 billion people in the world, we should be doing about 62 million cataract surgeries a year, or about 2.5 times our current number. Every year there are more patients in the world living with visual impairment from cataract who could be “cured” with a safe and effective 20-minute surgical procedure. The challenge here is human and financial resource based, and we are falling further behind each year.
Globally, the estimated prevalence of age-related macular degeneration is 196 million, diabetic retinopathy/maculopathy 146 million, glaucoma 76 million, and corneal opacity and trichiasis near 7 million. The ABCD of ocular surface disease — allergy, blepharitis, conjunctivitis and dry eye — reduce quality of vision and quality of life for another 3 billion worldwide. While the patient with one or another ocular surface disease is not usually visually impaired on a Snellen chart, their visual performance and quality of life can suffer dramatically.
The cost of addressing the so-called “treatment gap” is estimated to be approximately $14.3 billion by WHO, which considering the $3 trillion U.S. annual health care budget seems surprisingly low to me. Arguably, the financial challenge is surmountable, but to date it has not been addressed. In my opinion, the greatest challenge is access to trained personnel to treat the visually impaired where they live. High-quality care close to home is the desire of every person for one’s self and those they love.
At this time, using the U.S. as an example, we have about 18,000 ophthalmologists and 42,000 optometrists to treat 360 million people. That is approximately one eye care provider per 6,000 population. To equal that ratio of trained eye care providers to population worldwide, we would need 1,283,000 eye doctors. While exact numbers are hard to come by, and definitions vary country to country, we have at best 400,000 eye doctors worldwide today. We are thus more than 800,000 eye doctors short globally, and of course not many would choose to live in sub-Saharan Africa, Siberia, Mongolia or, for that matter, rural Minnesota. So, even if the money suddenly appeared, we have a challenge delivering quality care close to home where it is needed.
Creativity and innovation are required to overcome this challenge, as we will never triple the number of well-trained eye doctors in the world. The WHO supports universal health coverage, eye care as an integral part of that universal health coverage, the adoption of integrated eye care delivery models using the best available community resources, people-centered care appropriate to the local environment, and continuous evaluation as progress is made toward reducing the magnitude and impact of visual impairment worldwide. These are worthy goals. The challenges are great, but the potential benefits even greater. In the words of WHO: “Vision, the most dominant of the senses, plays a critical role in every facet and stage of our lives.”
Disclosure: Lindstrom reports he is the founder and attending surgeon at Minnesota Eye Consultants, on the board of directors of Unifeye Vision Partners, and partner, shareholder, board of directors member, adviser and/or investor in numerous ophthalmic companies.