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Where the Current Data Takes Us on Myopia Control

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Where the Current Data Takes Us on Myopia Control Eye (2014) 28, 142–146 & 2014 Macmillan Publishers Limited All rights reserved 0950-222X/14 www.nature.com/eye 1,2,3 1,2,3 2,4 CAMBRIDGE OPHTHALMOLOGICAL SYMPOSIUM Myopia, an B Holden , P Sankaridurg , E Smith , T Aller2,5, M Jong1 and M He6 underrated global challenge to vision: where the current data takes us on myopia control Abstract Eye (2014) 28, 142–146; doi:10.1038/eye.2013.256; published online 20 December 2013 Myopia is the most frequent cause of distance impairment in the world and is creating an Keywords: blindness; myopia; myopia control; alarming global epidemic with deleterious vision impairment ramifications for the quality of life and economic health of individuals and nations as a whole. In addition to being immediately disadvantageous, myopia increases the risk of Prevalence of myopia and high myopia serious disorders such as myopic macular degeneration, retinal detachment, glaucoma, On the basis of world-wide prevalence of and cataract and is a leading cause of visual myopia, it can be estimated that over 22% of the 1 Brien Holden Vision Institute, impairment and blindness across many current world population, that is, 1.5 billion Sydney, Australia countries. The reduction in age of onset of people are myopic, and although myopia has 2Vision Co-operative Research myopia is of great concern since the earlier often been referred to as a ‘simple’ refractive Centre, Sydney, Australia the onset, the more myopic the individual error, even in lower amounts it enhances the will become, with all the attendant increased risk of serious eye disorders such as retinal 3 School of Optometry and Vision risks of accompanying debilitating eye detachment, cataract, and glaucoma. More Science, University of New South Wales, Sydney, Australia conditions. The economic burden is great; urgently perhaps, high myopia is emerging as both in consequences of uncorrected refractive the major cause of blindness in some Asian 4College of Optometry, University error and also in the provision of devices for countries. For example, myopic macular of Houston, Houston, TX, USA correcting visual acuity. Earlier onset of degeneration (MMD) is now the major cause 5 myopia increases the lifetime economic of permanent monocular blindness in Japan and Private Practice, Berkeley, CA, 1,2 USA burden related to loss of productivity and of new cases of blindness in Shanghai. On a independence, leading to a reduced quality of wider front affecting over 100 million children, 6Zhongshan Ophthalmic Centre, life. Recent data suggest addressing adults and elderly people with massive Sun-Yet Sun University, accommodation per se has little direct socio-economic consequences, uncorrected Guangzhou, China amelioration of myopia progression. myopia is the most frequent cause of distance 3 Correspondence: Pharmacological interventions that effect visual impairment in the world. B Holden, Brien Holden Vision changes in the sclera show promising efficacy, The prevalence of myopia is rising Institute, Level 4, Rupert Myers whereas optical interventions based on a dramatically, reaching 70–80% in many East Building, Gate 14, Barker B Street, Kensington, NSW 2052, myopic shift in the retinal image are proving Asian countries and 25–40% in Western Australia. to effect up to 55% reduction in the rate of countries;4–11 and high myopia (defined as Tel: +61 2 9385 7517; progression of myopia. Early contact lens and greater than À 6.00D) ranges from 6.8 to 38% in Fax: +61 2 9385 7401. 8,12–15 E-mail: b.holden@ spectacle interventions that reduce the rate of Asia. In the United States, myopia has brienholdenvision.org progression of myopia are able to significantly doubled in the last 30 years6 and the prevalence reduce the burden of myopia. These non- of myopia over 8.00D has risen eightfold. In Received: 30 September 2013 pharmacological interventions show profound China where there are B216 million individuals Accepted: 15 October 2013 16 Published online: 20 December promise in reducing the overall associated in the age range of 15–24 years and with a 2013 morbidity of myopia. prevalence of myopia in young adults aged Control of Myopia B Holden et al 143 15–25 years of over 75%, it is estimated that there are at population-based studies found myopia to be associated least 160 million young myopes and 16 million with with nuclear as well as posterior subcapsular cataracts.28 myopia over À 6.0D. The shift to a younger onset of Also, it has been reported that myopic eyes have an myopia is especially worrying as younger eyes increase in optic disc abnormalities such as optic nerve experience more rapid progression of myopia which crescents, tilted discs, and larger disc areas.17,29 could lead to even greater levels of high myopia than those currently being reported. Economic burden Blindness due to myopia For each and every individual with myopia, there are the The retinal abnormalities identified and associated with economic or financial considerations with both myopia include chorioretinal atrophy, lattice uncorrected refractive error and the cost of treatment of degeneration, pigmentary degeneration, lacquer cracks, the condition with optical devices or other refractive posterior staphyloma, Fuch’s spot, macular modalities and the need for frequent and degeneration, retinal breaks and detachment, and long-term management of the condition by the eye-care posterior vitreous detachment.17–20 These degenerative practitioner. The earlier the onset of myopia, the greater changes substantially increase the risk of loss of vision is this burden extending over many years and possibly and indeed in countries where the prevalence of myopia over the lifetime of the individual. The long-term is high, MMD has been identified as one of the leading management not only includes the need to monitor the causes of visual impairment and blindness. MMD was eye for any refractive error change but to also monitor the the most frequent cause of visual impairment and eye for risks associated with high levels of myopia. blindness in a population of elderly Chinese in Taiwan21 At a stage where myopia progresses and is categorised to and a pilot assessment of Hong Kong Chinese residents be high myopia, additional economic and health burdens aged 40 and over found myopic choroidal degeneration are imposed due to more frequent visits and complex to be the leading cause for impaired vision (o20/60 corrective strategies. In addition, in highly myopic eyes, visual acuity).22 Similarly, in a cross-sectional study even in the absence of retinal pathology or degeneration, conducted in Tajimi City, Japan, the primary cause for visual performance is frequently found to be reduced blindness was MMD.1 Interestingly, even in western and imposes a burden not dissimilar to those seen in eyes populations wherein the prevalence of myopia is less, with significant visual impairment resulting in loss MMD was frequently found to be a significant cause of of productivity, quality of life, and independence. visual impairment and blindness. The Copenhagen study Even without obvious retinal pathology, and in spite of found myopia-related retinal disorders to be the most attempts to fully correct the condition, the quality of common cause of impaired vision with MMD being the vision as indicated by best-corrected visual acuity is third most common cause of blindness.23 The Rotterdam compromised in highly myopic eyes. One reason for eye study24 found that in persons younger than 75 years, reduced vision is spectacle minification resulting in loss myopic degeneration was the most important cause of of resolution. Other reports have proposed that increased impaired vision.24 And in a more recently conducted, Los eye length contributing to retinal stretching and spacing Angeles Latino Eye Study, myopic degeneration was the of the cone mosaic, morphologic changes in the third most major cause of blindness.25 photoreceptor outer segment,30–32 and decreased In addition to retinopathy, increasing levels of myopia subfoveal choroidal thickness delivering less oxygen and is said to increase the risk of a number of other ocular nutrients to outer retina may have a role.33 Also, it was pathologies. The association between glaucoma and reported that there appeared to be a correlation between myopia has been reported across multiple, large, degree of myopia at age 14 and subsequent visual loss.34 population-based studies involving many ethnicities Clearly either loss of functional vision associated with with the odds of developing glaucoma rising with uncorrected refractive error or permanent vision loss increasing myopia. The Blue Mountains Eye Study significantly affect all aspects of the individual’s life. And reported an odds ratio of 2.3 for low myopia and 3.3 for at a stage where myopia causes significant visual moderate-to-high myopia (Z À 3.0D).26 A systematic impairment and blindness, the constraints experienced review of 11 population-based cross-sectional studies by affected individuals are likely to be different to those found the pooled odds ratio of the association between with functional vision, and is likely to further limit their low myopia (up to À 3.0D) and glaucoma to be 1.65 and choices in life and pose additional monetary and physical for myopia 4 À 3.0D to be 2.46.27 As with glaucoma, the burden.35 In addition to direct costs, there are a link between cataract and myopia has been reported significant burdens imposed due to the decrease in across many studies. A meta-analysis of large, productivity, loss of quality of life, and independence Eye Control of Myopia B Holden et al 144 among those affected that translates to a significant health and socio-economic burden for the society. Given the evidence that the number of eyes destined to become highly myopic is increasing along with the substantial burdens associated with the condition, the need to reduce the number of eyes becoming highly myopic is urgent.
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