Rapid assessment of avoidable blindness in Bhutan

Abstract

Aim: To conduct a rapid assessment of avoidable blindness survey in Bhutan to obtain estimates of blindness, visual impairment, and cataract surgical coverage, outcomes and barriers among persons ≥50 years old.

Methods: A total of 82 clusters of 50 people ≥50 years were selected using probability proportionate to size sampling. Eligible participants were selected from households using compact segment sampling, and underwent ophthalmic examination for visual acuity, followed by penlight and direct ophthalmoscopy. Participants with cataract were interviewed regarding surgical outcomes and barriers to surgery.

Results: Overall, 4046 of 4100 persons enumerated (98.7%) underwent ophthalmic examination. Adjusting for age and sex, the prevalence of bilaterally blind persons with available correction was 1.5% (95% confidence interval 1.09-1.89). Most blindness (67.1%) and severe visual impairment (74.1%) resulted from cataract, but 22.1% resulted from posterior segment pathology. Cataract surgical coverage for bilaterally blind persons was 72.7%. Almost 90% of patients reported moderate or good satisfaction, despite poor surgical outcomes in 23.6%.

Conclusions: The prevalence of blindness in people aged ≥50 years in Bhutan was relatively low when compared with neighboring countries and World Health Organization sub-region estimates. Areas for improvement include community outreach, surgical outcomes, and posterior segment diseases.