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3.1 Distribution of Myopia by Region, Age, Gender and Ethnicity

We can draw conclusions about the impact of different lifestyles, different environment, different nutrition, and different genetic heredity by comparing the variation in rates of myopia according to age in different regions. Some results are:

• An evaluation of statistical data for reported blindness due to malignant myopia in different states of the USA was done by compiling a chart with the rate of myopia per state, and distance to seacoast, annual hours of sunshine and the nutritional concentration of calcium, fluoride and selenium in each state. The following factors resulted in a higher probability of malignant myopia:⁷¹
- less sunshine,
- less calcium,
- less fluoride,
- less selenium and
- closer to a seacoast

• Myopia rates are higher in urban than in rural areas.^{90, 91, 92.}

Note:
Of course, farmers don't have much time to read.

• The frequency of myopia at children in various countries is⁹³:
- Germany - 10%,
- Taiwan, South Korea - 70%,
- Japan - 95%,
- Singapore - 74%⁹⁴
- Mexico - 44%⁹⁵

• Myopia recently worsened as a problem, as stated by Lin et al.⁹⁶: "In Taiwan, myopia was not a problem some 50 years ago"; today about 15% of the population have over - 7.0 D.

• 50 to 60 % of the Japanese are said to be myopic, but only 2 % of the people in South America are myopic⁹⁷. The author of this publication hints at a substantial difference with respect to spontaneity between these two populations.

• The incidence of myopia in Japan was increasing from 15% in 1920 to 36% in 1940 to between 50 and 60% in 1985⁹⁷.

• Sherpa and Tibetan children in Nepal have the same ancestry and genetic history, but the prevalence of myopia is 2.7% for Sherpa children and 21.7% for Tibetan children⁹⁸. This difference was attributed to more rigorous schooling and higher advanced technology in Tibet.

Note:
Generally more rigorous schooling and higher advanced technology are going hand in hand with a change in nutrition and increased mental stress. For the impact of nutrition on myopia see section 3.16, for the impact of stress see section 3.13.1.

• Results of a study on Eskimos⁹⁹ are shown in Table 2.

Table 2 Percentage of myopes among Eskimos

• Data about the degree of myopia in various populations¹⁰⁰ are shown in Table 3.


Table 3 Percentage of myopes among various populations

• A study from 2001¹⁰³, giving the percentage of myopic males (at least -0.5 D) between age 16 and 25 in Singapore:

82.2 % Chinese
68.7% Indians
65.0% Malays

• Another statistic from USA (children, age 5-17 years)¹⁰⁴ is shown in Table 4.


Table 4 Percentage of myopes among various populations in the USA

• Typical childhood progression rates were found to be between – 0.2 D and – 0.6 D in Europe and USA, and between – 0.5 D and – 0.8 D in Japan¹⁰⁵.
• In spite of similar myopia rates of Malays and Chinese, the age dependent progression profile appears to be rather different¹⁰⁶.
• Results from Singapore and Hong Kong show that myopia is 1.5 to 2.5 times more prevalent among adult Chinese than in corresponding European-derived populations, and that women have significantly higher myopia rates than men^{107, 108}. Moreover, as stated by Choo109, "...severity of myopia rises by about 1.5 D per year in Singapore children, compared with 0.5 D per year in US children."
• The higher rate of female myopes is confirmed by results about Greek students: 46% female students, and 29.7% male students are myopic¹¹⁰.
• Dayan found111: "During the 13 years from 1990 to 2002, the prevalence of myopia significantly increased among the Israeli population. Although there was an association with the level of education, gender, ethnicity, and origin, the prevalence of myopia increased on an annual basis, independent of these factors."

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