ISSN 2630-0583 (Print)
ISSN 2630-0656 (Online)
Journal of Current Science and Technology
Rangsit Journal of Arts and Sciences. Vol.2 No.2 , July - December 2012.
Refractive errors: the major visual impairment in Thailand.
In Thailand, three national surveys of blindness were done in 1981, 1984 and 1994; the prevalence of blindness was shown to be 1.14%, 0.56% and 0.31%. Refractive errors were not included in the cause of blindness and low vision previously. In the fourth national survey of blindness, low vision and visual impairment in Thailand, conducted in 2006, refractive errors causing visual impairment were included in the questionnaire and eye examination. The survey was done by using the sample groups that were a stratified, cluster random sampling representing the whole country. A total of 42 districts from 21 provinces and Bangkok numbering 21,711 people (male 7,899, female 13,812), age ranges from 1 to 98 years, were enrolled in the study. For analysis of the survey data, national population census figures on July 1st, 2006 were used. The results found that after age and sex adjustment, age and sex specific blindness and low vision prevalence (WHO definition) was 0.59% and 1.57%. For blindness, males : females were 1.03:0.29 but for low vision, females : males were 1.93:0.93. The estimated number of people classified as blind and low vision were 369,013 and 987,993, respectively. The most common visual impairment was refractive error without eye glasses. Estimated total population with refractive errors was 15,301,032 of which 101,602 were blind and 304,443 were classified as low vision. In conclusion, the prevalence of visual impairments increased with age. Uncorrected refractive errors were the most common cause of bilateral visual impairment across all decades of life, rising from 11% in <10 year-old age group to 27% in educated age group (20 year-old and less) and 49% in young working age group (21-40 year-old). In the 40-60 year-old age group, if presbyopia was excluded, the prevalence of refractive errors was 16% and increased to 26% in 61-70 year-old, 59% among those aged 70 years and older. Refractive error was the easiest and cheapest visual impairment to solve with the highest return on investment and increase in quality of life.