Visual impairment and refractive error in school children in Bhutan: The findings from the Bhutan School Sight Survey (BSSS 2019)

• Published in: PloS one Vol. 15; no. 9; p. e0239117
• Main Authors: Sharma, Indra Prasad, Lepcha, Nor Tshering, Lhamo, Tshering, Ellwein, Leon B., Pokharel, Gopal Prasad, Das, Taraprasad, Sapkota, Yuddha Dhoj, Dorji, Tandin, Peldon, Sonam
• Format: Journal Article
• Language: English
• Published: San Francisco Public Library of Science 14.09.2020; Public Library of Science (PLoS)
• Subjects: Acuity; Age; Astigmatism; Biology and Life Sciences; Childhood vision disorders; Children; Children & youth; Demographic aspects; Education; Errors; Eye; Eye (anatomy); Eyewear; Field study; Gender; Health planning; Human subjects; Hyperopia; Impairment; Mass media effects; Medicine and Health Sciences; Myopia; Pediatric research; People and Places; Physical disabilities; Polls & surveys; Public health; Public schools; Refraction; Refractive errors; Sample size; Schools; Social classes; Social Sciences; Statistics; Supervision; Urban education; Vision; Vision disorders; Visual acuity; Visual impairment; Bhutan; East Asia; Nepal; India
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0239117

To estimate the nationwide prevalence of visual impairment and associated refractive error in school children in Bhutan. The sample of this prospective cross-sectional national survey comprised of randomly selected classes in levels IV-IX (age 10 to 15 years) from schools throughout Bhutan. The examination included measurement of visual acuity (VA), evaluation of ocular motility, refraction under cycloplegia, examination of the external eye, media and fundus. The principal cause of impairment was determined for eyes with uncorrected VA [less than or equal to]6/12. The main outcome measures were distance VA and cycloplegic refractive error. With a sampling frame of 1967 class-based clusters from 190 schools, 160 classes in 103 schools were randomly selected; 4985 (98.5%) of 5060 enumerated children were examined. The prevalence of uncorrected, presenting, and best-corrected visual impairment (VA[less than or equal to]6/12) in the better eye was 14.5%, 12.8%, and 0.34%, respectively. Refractive error was the principal cause (94.2%) of impaired vision and 88% of children who could achieve VA [greater than or equal to]6/9 with best correction were without necessary spectacles. The prevalence of myopia ([less than or equal to] -0.5 D) was 6.64% and was associated with female gender (P = 0.004), urban schooling (P = 0.002), and greater parental education (P<0.001). The prevalence of hyperopia ([greater than or equal to] +2.0 D) was 2.17% and was significantly associated with lower class-level (P = 0.033), and female gender (P = 0.025). The overall prevalence of astigmatism ([greater than or equal to] 0.75 D) was 9.75%. Reduced vision because of uncorrected refractive error is a public health problem among school-age children in Bhutan. Effective school eye health strategies are needed to eliminate this easily treatable cause of visual impairment.