Global issues Br J Ophthalmol: first published as 10.1136/bjophthalmol-2017-311266 on 26 April 2018. Downloaded from Global prevalence of visual impairment associated with myopic macular degeneration and temporal trends from 2000 through 2050: systematic review, meta-analysis and modelling Timothy R Fricke,1 Monica Jong,1,2 Kovin S Naidoo,1,2,3 Padmaja Sankaridurg,1,2 Thomas J Naduvilath,1 Suit May Ho,1 Tien Yin Wong,4 Serge Resnikoff1,2 ► Additional material is ABSTRACT The prevalence of myopia and high myopia has published online only. To view Purpose We used systematic review and meta-analysis been observed to be increasing globally.2 While this please visit the journal online appears most dramatic in young East Asians, it is (http:// dx. doi. org/ 10. 1136/ to identify and assimilate evidence quantifying blindness bjophthalmol- 2017- 311266). and visual impairment (VI) associated with myopic increasingly observed across other regions and age macular degeneration (MMD), then derived models groups.2 Trends in lifestyle, education and demo- 1 Brien Holden Vision Institute, to predict global patterns. The models were used to graphics mean global myopia and high myopia prev- Sydney, Australia alence is projected to continue rising.2 Estimates of 2School of Optometry and Vision estimate the global prevalence of blindness and VI Science, University of New associated with MMD from 2000 to 2050. the impact of this trend on the epidemiology of VI South Wales, Sydney, Australia Methods The systematic review identified 17 papers from MMD would inform planning for prevention 3 African Vision Research with prevalence data for MMD VI fitting our inclusion and management of the problem. However, despite Institute, University of KwaZulu- many prevalence studies on myopia, there are no Natal, Durban, South Africa criteria. Data from six papers with age-specific data were 4 estimates of the regional or global prevalence of Singapore Eye Research scaled to relative age-dependent risk and meta-analysed Institute, Singapore National at VI and blindness levels. We analysed variance in all VI caused by high myopia or MMD, or projected Eye Center, Duke-NUS Medical MMD VI and blindness data as a proportion of high future changes. School, National University of This paper reviews population-based and blind- Singapore, Singapore, Singapore myopia against variables from the place and year of data collection, with a model based on health expenditure ness registry studies to estimate the global preva- providing the best correlation. We used this model to lence of VI/blindness associated with MMD, with Correspondence to modelling and projections to 2050. An expanded Professor Kovin S Naidoo, estimate the prevalence and number of people with background and additional references can be found Brien Holden Vision MMD VI in each country in each decade. Institute, University of New in online supplementary file 1. South Wales, Kensington, NSW Results We included data from 17 studies comprising 2052, Australia; k. naidoo@ 137 514 participants. We estimated 10.0 million brienholdenvision. org people had VI from MMD in 2015 (prevalence 0.13%, METHODS 95% CI 5.5 to 23.7 million, 0.07% to 0.34%), Studies, databases and data organisation http://bjo.bmj.com/ Received 31 August 2017 3.3 million of whom were blind (0.04%, 1.8 to 7.8 We performed a systematic review of the preva- Accepted 27 March 2018 lence of VI and blindness associated with MMD, Published Online First million, 0.03% to 0.10%). We estimate that by 26 April 2018 2050, without changing current interventions, VI summarised in figure 1. Sixteen papers were included in our analysis of the prevalence of MMD from MMD will grow to 55.7 million people (0.57%, VI/blindness.6–21 One additional paper was identi- 29.0 to 119.7 million, 0.33% to 1.11%), 18.5 million fied as having useful information on the age spread of whom will be blind (0.19%, 9.6 to 39.7 million, on September 29, 2021 by guest. Protected copyright. of myopia-related VI.4 0.11% to 0.37%). The epidemiology of high myopia was taken from Conclusion The burden of MMD blindness and VI a systematic review and meta-analysis of the prev- will rise significantly without efforts to reduce the alence of myopia and high myopia.2 We searched development and progression of myopia and improve for alternative models, but no comparable evidence the management of MMD. was found. Country-specific population data for each decade from 2000 through 2050, in 10-year age groups from 0 to 90+, were drawn from the United Nations INTRODUCTION Department of Economic and Social Affairs.22 Uncorrected refractive error is the main cause of Countries were aggregated into the 21 Global presenting visual impairment (VI) globally, and Burden of Disease regions for data presentation.1 myopia is the most common refractive error.1 2 Even with refractive correction, those with myopia Definitions are at higher risk of a range of conditions, including High myopia was classified as spherical equivalent cataract, glaucoma, retinal pathologies such as tears ≤−5.00 D in line with international agreement.23 and detachment, and myopic macular degeneration MMD was defined as degenerative changes in To cite: Fricke TR, Jong M, 3–5 Naidoo KS, et al. (MMD). MMD alone has been found to cause the macula, including diffuse or patchy chorio- Br J Ophthalmol 12.1% of VI (approximately 200 000 people) in retinal atrophy, lacquer cracks, choroidal neovas- 2018;102:855–862. Japan.6 cularisation and atrophy related to choroidal Fricke TR, et al. Br J Ophthalmol 2018;102:855–862. doi:10.1136/bjophthalmol-2017-311266 855 Global issues Br J Ophthalmol: first published as 10.1136/bjophthalmol-2017-311266 on 26 April 2018. Downloaded from Figure 1 Flow diagram summarising the systematic search, using medical subject headings (MeSH) terms, and review process for identifying evidence on the prevalence of MMD VI and/or blindness. Our inclusion criteria were population-based or blindness registry studies quantifying prevalence, with sampling representative of whole communities. Exclusion criteria were unspecified or ambiguous definitions, not specifying the number of eligible participants, participation rate <75%, use of data duplicating other included studies or aggregating MMD VI with other conditions (eg, all macular conditions). MMD, myopic macular degeneration; VI, visual impairment. http://bjo.bmj.com/ neovascularisation, in the presence of higher levels of myopia.24 We applied these age-specific relative risks of VI/blindness While MMD can occur in younger eyes with relatively low associated with MMD to data from all 16 papers in our main levels of myopia, it is more likely to occur in older, longer, more analysis, scaled to ensure that the overall VI/blindness associated 4 5 myopic eyes. Consequently, we translated the epidemiological with MMD remained equivalent to the primary data. We then evidence from population prevalence for a specific age group, combined age-specific MMD VI and blindness in 10-year age year of data collection, country and urbanisation level into groups with the prevalence of high myopia data from the same on September 29, 2021 by guest. Protected copyright. proportions of people with high myopia who have MMD VI urbanisation level of the same country, decade and age groups,2 2 using matched high myopia data. These proportions enabled to give the proportion of people with high myopia over 40 years more meaningful intercountry comparisons. of age who have MMD VI/blindness. We used the WHO definitions of VI (visual acuity worse than Analysis of the proportion data suggested there is some factor 6/18) and blindness (visual acuity worse than 3/60).25 beyond the prevalence and age distribution of high myopia that affects not the prevalence of MMD itself but vision outcomes Meta-analysis and modelling associated with MMD. Suspecting a factor related to coun- Six papers provided detailed information on the relationship try-level detection and management of myopia and consequent between age and prevalence of MMD VI and blindness.4 8 10 13 14 18 ability to prevent vision loss, we analysed the study time-specific Data from these six papers were scaled to relative age-dependent and place-specific proportion of people with high myopia who risk in 10-year age groups from 0 to 90+. We used a standard meta-analysis tool (Comprehensive Meta-Analysis (V.3, Biostat, have MMD VI or blindness against variables describing coun- Englewood, New Jersey, USA)) to perform a weighted analysis try-level development (full list and sources provided in online of the relative risk in each age group. Regression analysis of the supplementary file 1). The following were the best correlations 2 meta-analysis results against age found that exponential curves for the proportion of high myopes with MMD VI (r =0.77) and 2 with r2 of 0.93 and 0.96 best described the relative risk of VI and blindness (r =0.85): blindness, respectively: VI attributed to MMD = 0.1376 exp(0.0008 (HE)), and ∗ ∗ (0.0756 (age)) Blindness attributed to MMD = 0.0473 exp(0.0009 (HE)), Relative risk of MMD VI = 0.00002 exp ∗ , and ∗ ∗ ∗ (0.0796 (age)) Relative risk of MMD blindness = 0.00001 exp ∗ . ∗ where HE=health expenditure per capita in US$. 856 Fricke TR, et al. Br J Ophthalmol 2018;102:855–862. doi:10.1136/bjophthalmol-2017-311266 Global issues Br J Ophthalmol: first published as 10.1136/bjophthalmol-2017-311266 on 26 April 2018. Downloaded from The equations are based on primary evidence covering 73% Confidence intervals of the global