Variability in testing and data collection methods makes comparisons of prevalence and progression difficult.The prevalence of myopia has been reported as high as 70–90% in some Asian countries, 30–40% in Europe and the United States, and 10–20% in Africa. Myopia is about twice as common in Jewish people than in people of non-Jewish ethnicity. Myopia is less common in African people and associated diaspora. In Americans between the ages of 12 and 54, myopia has been found to affect African Americans less than Caucasians. Asia
In some parts of Asia, myopia is very common. Singapore is believed to have the highest prevalence of myopia in the world; up to 80% of people there have myopia, but the accurate figure is unknown. Chinas myopia rate is 31%: 400 million of its 1.3 billion people are myopic. The prevalence of myopia in high school in China is 77%, and in college is more than 80%. In some areas, such as China and Malaysia, up to 41% of the adult population is myopic to 1.00 dpt, and up to 80% to 0.5 dpt. A study of Jordanian adults aged 17 to 40 found over half (54%) were myopic. Some research suggests the prevalence of myopia in Indian children is less than 15%. Europe
In first-year undergraduate students in the United Kingdom 50% of British whites and 53% of British Asians were myopic. A recent review found 27% of Western Europeans aged 40 or over have at least −1.00 diopters of myopia and 5% have at least −5.00 diopters.
Myopia has been increasing rapidly throughout the developed world, suggesting environmental factors are involved.A single-author literature review in 2021 proposed that myopia is the result of corrective lenses interfering with emmetropization. Genetics
A risk for myopia may be inherited from ones parents. Genetic linkage studies have identified 18 possible loci on 15 different chromosomes that are associated with myopia, but none of these loci is part of the candidate genes that cause myopia. Instead of a simple one-gene locus controlling the onset of myopia, a complex interaction of many mutated proteins acting in concert may be the cause. Instead of myopia being caused by a defect in a structural protein, defects in the control of these structural proteins might be the actual cause of myopia. A collaboration of all myopia studies worldwide identified 16 new loci for refractive error in individuals of European ancestry, of which 8 were shared with Asians. The new loci include candidate genes with functions in neurotransmission, ion transport, retinoic acid metabolism, extracellular matrix remodeling and eye development. The carriers of the high-risk genes have a tenfold increased risk of myopia. Aberrant genetic recombination and gene splicing in the OPNLW1 and OPNMW1 genes that code for two retinal cone photopigment proteins can produce high myopia by interfering with refractive development of the eye.Human population studies suggest that contribution of genetic factors accounts for 60–90% of variance in refraction.