New technologies to improve global eye health

Statistics show that vision impairment is on the rise. In fact, over 600 million people worldwide suffer from uncorrected refractive error.^1,2 Two of the most common and rapidly increasing refractive error conditions are myopia and presbyopia.

In 2010, nearly 1.4 billion people were impacted by myopia worldwide, and this number is expected to increase to 2.5 billion by 2020, with a significant number living in urban areas of Asia. In Singapore, approximately 70% of college graduates have myopia,³ and in China, studies have shown that as many at 78% of 15-year-old living in urban areas of southern China children have the condition.⁴ As a result of the world’s aging population and increased life expectancy, presbyopia is also growing and is estimated to affect 1.5 billion people by 2050.²

Among all of the important public health priorities, vision impairment is one of the top causes of loss of wellbeing-ranking just below HIV/AIDS.⁵ If left untreated, conditions like myopia and presbyopia can have an immense effect on people’s performance at school, employment opportunities and, ultimately, quality of life.^6,7

The correction of myopia and presbyopia is not only a humanitarian imperative; there is also a heavy economic cost to the community, particularly resulting from reduced productivity. The global economic burden of vision impairment ranks among cancer, dementia, and arthritis,⁸ with the cost of global lost productivity resulting from uncorrected refractive error estimated at US$202 billion.^9,10 By contrast, the cost of correcting all global uncorrected refractive error is estimated between US$20 billion and US$28 billion.¹⁰

Slowing the progression of myopia

While glasses can help correct the problem of poor vision, they don’t treat or prevent it. For a condition such as myopia, they are especially ineffective because they aren’t able to slow or halt the progression to high levels of myopia, which significantly increases the risk of developing potentially blinding conditions including myopic macular degeneration (MMD), retinal damage, retinal detachment, glaucoma, and cataract.

Specifically, evidence is mounting that MMD will become the major cause of blindness in Asia and a growing threat for many other countries where the prevalence of myopia is on the rise. In fact, a meta analysis conducted in 2006 found that the impact of myopia may be greater than it seems and that a better understanding of the risks of the condition by eyecare practitioners may help facilitate the screening and management of myopia-related ocular complications.¹¹

Data from Asia also provides some understanding of the magnitude of this emerging threat. A recent study found that MMD is now the leading cause of blindness in Jing-An District, Shanghai, China, with rates of blindness increasing from 114 out of 100,000 people in 2003 to 166 out of 100,000 people in 2009.¹² Additionally, in the U.S. there is clear evidence that myopia is on the rise, but worryingly, there is little knowledge about the potential impact on levels of blindness.^13,14

Research and subsequent action are essential to combat the health concerns associated with this increasing prevalence of eye conditions. In the area of myopia, researchers around the world are looking at different approaches to treat the condition by reducing its rate of development and preventing its progression to the higher levels which significantly increases the risk of blindness. In the field of presbyopia and cataract, a range of surgical treatments such as an  intra-ocular lens (IOL) are being pursued.

Brien Holden Vision Institute is continuously looking at ways of reducing the incidence of refractive error in addition to employing the normal corrective measure, glasses. This is currently being achieved through a variety of projects, including the Myopia Control Program, Accommodating Gel Project, and the Intelligent Retinal Camera Project.

Myopia Control Program

The rate of increase in myopia can be slowed by an optical intervention based on bringing the peripheral focus closer to, on or in front of the retina.¹⁵ In collaboration with the University of Houston, the Brien Holden Vision Institute is working to translate this technology into contact lenses and spectacle treatments.

Through the program, several spectacle lenses were designed and developed in collaboration with industry partner Carl Zeiss Vision. These lenses were then assessed in a one-year trial conducted at the Zhongshan Ophthalmic Center, Guangzhou, China. The results of the trial showed a reduction in myopia progression by 30% in children between the ages of 6 and 12-years-old (with at least one myopic parent) and led to the development of the first myopia control spectacle lens. Results from this trial and subsequent studies have also generated invaluable information that has been used in designing and testing the next generation myopia control spectacle lenses. Contact lens studies have been even more rewarding with a steady 40% reduction in rate of progress of myopia using lenses testing the Earl Smith strategy of reducing peripheral hyperopia. Such a reduction would result in far less children developing high myopia with its attendant risks.

Accommodating Gel Project

Cataracts are presently the leading cause of blindness and the second largest cause of vision impairment in the world. In 2010, there were an estimated 24 million Americans 40-years-old and over with cataracts and this number is predicted to increase to approximately 50 million by 2050.¹⁶

Through the Accommodating Gel project, Adventus Technology, Inc., as subsidiary of the Brien Holden Vision Institute, and collaborators in the Vision Cooperative Research Centre (Vision CRC) are developing a clear gel-lens system that will replace old presbyopic or cataractous lenses of the eye. Existing technology doesn’t restore the eye’s natural ability to focus, but the Accommodating Gel technology could potentially provide an alternative for lens replacement in cataract surgery procedures, during which the opaque lens is removed and replaced by a synthetic IOL.

Intelligent Retinal Camera Project

Through stimulus funding provided by the Australian Government’s Cooperative Research Centre Program, Brien Holden Vision Institute and collaborators in the Vision CRC based in Sydney are developing imaging technology for a breakthrough retinal camera that will enable real-time detection and assessment of common blinding eye disease and general health disorders.

The intelligent retinal camera is intended to be able to accurately and rapidly detect and eventually diagnose sight-threatening conditions such as diabetic retinopathy and glaucoma. Additionally, it is being designed for use in the most extreme environments, so that it can be operated by technical support staff in remote and under-served locations worldwide.

Additional information on the global impact of avoidable blindness and the research being conducted by Brien Holden Vision Institute can be found in A Vision for All to See: A report on global eye health and vision care.ODT

References

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3. Au Eong KG, Tay TH, Lim MK. Education and myopia in 110,236 young Singaporean males. Singapore Med J. 1993 Dec;34(6):489-92

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13. Vitale S, Sperduto RD, Ferris FL 3rd. Increased prevalence of myopia in the united states between 1971-1972 and 1999-2004. Arch Ophthalmol. 2009 Dec;127(12):1632-9.

14. Myopia. National Eye Institute. http://www.nei.nih.gov/eyedata/myopia.asp#4. Accessed 12/10/13.

15. Sankaridurg P, Donovan L, Varnas S, et al. Spectacle lenses designed to reduce progression of myopia: 12-month results. Optom Vis Sci. 2010 Sep;87(9):631-41.

16. Cataracts. National Eye Institute. http://www.nei.nih.gov/eyedata/cataract.asp#4. Accessed 12/10/13.