The prevalence of myopia has been reported in several Caucasian populations: 28.1% in the Baltimore Eye Survey
3 (aged 40–80+ years), 26.2% in the Beaver Dam Eye Study
4 (aged 43–84 years), 15% in the Blue Mountains Eye Study
5 (aged 49–97 years), and 17% in the Visual Impairment Project
6 (aged 40–98 years). In East Asia, the prevalence of myopia is higher: 38.7% in Singapore Chinese aged 40–79 years
7 and 41.5% in Japanese aged over 40 years.
8 In Indian population-based studies, the Andhra Pradesh Eye Disease Study
9 and the Chennai Glaucoma Study
10 reported age-adjusted prevalence rates for myopia of 34.6% and 31.0%, among adults aged 40 years or older, respectively.
9,10 The prevalence of myopia of adults aged over 30 years was 17% in Central India
11 and 19.4% in Indians with diabetes aged over 40 years.
12 An interesting finding in the Andhra Pradesh Eye Disease Study is that the prevalence of myopia was significantly higher among rural than urban residents (38.0% vs. 31.9%;
P = 0.001),
9 in contrast to the perception that myopia is less common in rural communities.
13,14 However, the higher prevalence of myopia in rural India could be explained by the more severe nuclear cataract.
9 Nuclear cataract has been found to cause myopic shift in many studies, which reflects the increased power of the lens rather than increased axial length.
6,15 –17