Tribal Odisha Eye Disease Study # 4: Accuracy and utility of photorefraction for refractive error correction in tribal Odisha (India) school screening.

PURPOSE

To compare the photorefraction system (Welch Allyn Spot™) performance with subjective refraction in school sight program in one Odisha (India) tribal district.

METHODS

In a cross-sectional study school students, aged 5-15 years, referred after the preliminary screening by trained school teachers received photoscreening and subjective correction. The photoscreener was compared to subjective refraction in the range of +2D to -7.5D. Statistical analysis included Friedman nonparametric test, Wilcoxon signed-rank test, linear regression, and Bland-Altman plotting.

RESULTS

The photoscreener was used in 5990 children. This analysis included 443 children (187 males, 256 females, and the mean age was 12.43 ± 2.5 years) who received both photorefraction and subjective correction, and vision improved to 6/6 in either eye. The median spherical equivalent (SE) with spot photorefraction was 0.00 D (minimum -5.0D; maximum +1.6 D), and with subjective correction was 0.00D (minimum -6.00 D; maximum +1.5 D). The difference in the SE between the two methods was statistically significant (P < 0.001) using Friedman nonparametric test; it was not significant for J 45 and J 180 (P = 0.39 and P = 0.17, respectively). There was a good correlation in linear regression analysis (R = 0.84) and Bland-Altman showed a good agreement between photorefraction and subjective correction in the tested range.

CONCLUSION

Photorefraction may be recommended for autorefraction in school screening with reasonable accuracy if verified with a satisfactory subjective correction. The added advantages include its speed, need of less expensive eye care personnel, ability to refract both eyes together, and examination possibility in the native surrounding.