The Global Problem of Blindness and Visual Dysfunction Vasudevan Lakshminarayanan* School of Optometry and Departments of Physics and Electrical and Computer Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L3G1 & Michigan Center for Theoretical Physics, University of Michigan, Ann Arbor, MI.41809, USA ABSTRACT According to World Health Organization statistics there are approximately 285 million people who are blind, have severe low vision, or are near-blind. Of these, 39 million are blind, and 246 million have low vision problems. About 90% of these live in developing countries. The major causes are uncorrected refractive errors (42%), and cataracts (38%). In the US, there are about 6 million people over the age of 65 who have age-related macular degeneration which is the leading cause of blindness. For each decade after age 40, it is found that there is a three-fold increase in the prevalence of blindness and low vision. This paper will address the question of what can we, as optical physicists and engineers, do? There is a need for efficient methods to detect problems, investigate function, provide solutions, and develop rehabilitation devices for the visually impaired. Here I will sketch out the magnitude and variety of the problem, examples and future research directions. Keywords: Vision, Blindness, Visual Dysfunction, rehabilitation devices, public health, medical and ophthalmic optics, photo-refraction, retinal implants 1.The Magnitude of the Problem According to World Health Organization statistics 1,2 there are approximately 285 million people who are blind, have severe low vision or near blind. Of these 39 million are blind, and 246 million have low vision problems. About 90% of these live in developing countries. In spite of the progress made in surgical techniques and intraocular lens advancements, cataract (47.9%) remains the leading cause of visual impairment in all areas of the world, except for developed countries. Other main causes of visual impairment in 2002 (the last year for available global statistics) are glaucoma (12.3%), age-related macular degeneration (AMD) (8.7%), corneal opacities (5.1%), diabetic retinopathy (4.8%), childhood blindness (3.9%), trachoma (3.6%), and onchocerciasis (0.8%). These visual impairments in general are avoidable. In the least-developed countries, and in particular sub-Saharan Africa, the causes of avoidable blindness are primarily, cataract (50%), glaucoma (15%), corneal opacities (10%), trachoma (6.8%), childhood blindness (5.3%) and onchocerciasis (4%). Looking at the global distribution of avoidable blindness based on the population in each of the WHO regions, (see reference 1) we see the following: South East Asian 28%, Western Pacific 26%, African 16.6%, Eastern Mediterranean 10%, the American 9.6%, and European 9.6%. In addition the number of children represented in this data is about 19 million, of whom 12 million have refractive conditions. The global distribution of visual impairment is given in Table 1. In developed countries, the problem is slightly different. In the US, for example, there are about 6 million people over the age of 65 who have age related macular degeneration (AMD), which is the leading cause of blindness. The prevalence data 3 in percentage of the population is given in Table 2. In the table, blindness as defined by the U.S. definition is the best-corrected visual acuity of 6/60 or worse (=20/200) in the better-seeing eye; low vision is defined as the best-corrected visual acuity less than 6/12 (<20/40) in the better-seeing eye (excluding those who were categorized as being blind by the U.S. definition. It should be noted that for the population over the age of 40 years, the number of individuals having vision impairment is about 3.3 million; the number of individuals suffering from cataracts, AMD and glaucoma is about 31.8 million. In terms of diabetic retinopathy, the prevalence of Diabetes Mellitus in the US population is about 10.2 million (in 2004); out of this population, about 4.1 million have diabetic retinopathy 4 . More than two million Americans age 50 and older have advanced AMD, the stage that can lead to severe vision impairment and * Vengu@uwaterloo.ca , Phone: +1(519) 888-4567 x 38167 Fax: +1(519) 725-0784 Photonic Innovations and Solutions for Complex Environments and Systems (PISCES), edited by Akhlesh Lakhtakia, Judith A. Todd, Proc. of SPIE Vol. 8482, 84820A © 2012 SPIE · CCC code: 0277-786/12/$18 · doi: 10.1117/12.928050 Proc. of SPIE Vol. 8482 84820A-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 04/29/2014 Terms of Use: http://spiedl.org/terms