Comparison between focometer and autorefractor in the measurement of refractive error among students in underserved community of sub-Saharan Africa

Abstract

Purpose To compare focometer and autorefractor in the measurement of refractive errors among students in an underserved community of sub-Saharan Africa. Methods The study was a descriptive comparative cross-sectional study conducted in October/November 2014 among secondary school students of Ijaiye-Orile, Oyo State, Nigeria. Students were selected using systematic random sampling method. Ocular examination and measurement of refractive error was carried out on each student using a focometer and an autorefractor. Results A total of 230 students were studied. Mean age of the students was 15.1±1.9 years with a range of 13-21 years. Refractive error was detected in 95 (41.3%) of the students using autorefractor and in 81 (35.2%) with focometer. Among those found to have refractive error using autorefractor, 75 (78.9%) students had a difference of ≤±0.75 DS between the autorefractor and focometer readings. The sensitivity and specificity of the focometer relative to the autorefractor was 73.7% and 91.9%, respectively. Conclusion The focometer is comparable to the autorefractor in the measurement of refractive error because of its high sensitivity and specificity. The high positive and negative predictive values makes the focometer an effective tool for both screening and diagnosis of refractive error in rural areas among secondary schools students. Its use would make refractive service available and affordable to individuals living in the resource poor rural communities thereby reducing the burden of refractive error in such areas. The focometer should also be a useful tool in school eye health programs.