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Bhutan is the only country in the southeast Asia region to have completed a nationwide Rapid Assessment of Avoidable Blindness (RAAB) survey in 2018 and a nationwide Refractive Error in School Children (RESC) survey in 2019. It has been considered that, if the school enrollment in any country is over 90%, the school children survey is also considered as a population-based survey of that age group.
The WHO Member States endorsed in the World Health Assembly resolution 73.4 on Integrated People-Centred Eye Care that eye care is essential to achieving Universal Health Coverage. In July 2021, we had the first ever UN resolution on vision.
The Covid pandemic delayed the operationalization of these resolutions into national eye health policy and plan. But with improved vaccination coverage in many countries now we need to start working on embedding these global eye health endorsements in national eye health policy and plan.
It is essential to obtain baseline data/evidence on Effective Cataract Surgical Coverage and Effective Refractive Error Coverage. The targets are a 40 percentage point increase in effective coverage of refractive error by 2030, and a 30 percentage point increase in effective coverage of cataract surgery by 2030. Countries should aim to achieve an equal increase in all relevant population subgroups.
This requires population-based surveys. The above surveys in Bhutan provide the required baseline data for Bhutan to set the target for 2030.
The prevalence of uncorrected, presenting, and best-corrected visual impairment (VA<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 equal or better than 6/9 with best correction were without necessary spectacles.
Based on this information the calculation of baseline data for Bhutan eREC will be as follows:
Total Visual Impairment due to Refractive Error (14.5% *0.942) = 13.7%
The difference between uncorrected and presenting visual impairment (14.5-12.8) = 1.7% is met need and (13.7-1.7) =12.0 % unmet need.
Only 12.4% of vision impaired due to refractive error are wearing appropriate correction and 87.6% of people are with refractive error are visual impaired due to refractive error could have improved with appropriate correction.
So eREC target for Bhutan school children for 2030 would be 17.4%.
CSC Data of RAAB Survey 2018:
|Cataract Surgical Coverage|
|Cataract Surgical Coverage (persons) – percentage|
|VA < 3/60||91.3||82.8||86.1|
|VA < 6/60||86.4||81.1||83.2|
|VA < 6/18||51.4||59.1||55.6|
|Effective Cataract Surgical Coverage (persons) percentage|
|VA < 3/60||68.8||66.4||67.3|
|VA < 6/60||62.5||62.9||62.7|
|VA < 6/18||33.9||44.2||39.5|
As RAAB- 6 and RAAB-7 directly calculated the eCSC data no further calculation is required to generate eCSC data. Based on these evidence Bhutan need to set the eCSC target for 2030 on VA category 6/18, at least 44.1% for male, 57.5% for female cataract person.
 Sharma IP, Lepcha NT, Lhamo T, Ellwein LB, Pokharel GP, Das T, et al. (2020) Visual impairment and refractive error in school children
in Bhutan: The findings from the Bhutan School Sight Survey (BSSS 2019). PLoS ONE 15(9): e0239117. https://doi.org/10.1371/journal.
 Lepcha NT, Sharma IP, Sapkota YD, Das T, Phuntsho T, Tenzin N, et al. (2019) Changing trends of blindness, visual impairment and cataract
surgery in Bhutan: 2009–2018. PLoS ONE 14(5): e0216398. https://doi.org/10.1371/journal.pone.0216398