The performance of Spot photoscreener compared to cycloplegic retinoscopy refraction in 6 to 10 weeks old human infants

Background To compare the refractive errors measured by the Spot photoscreener with or without cycloplegia to cycloplegic retinoscopy in 6 to 10 weeks old human young infants. Methods A total of 101 right eyes from 101 healthy infants aged from 6 to 10 weeks were recruited in this cross-sectional observational study. Refractive errors were measured using Spot photoscreener before and after cycloplegia as well as cycloplegic retinoscopy. Comparisons between the refractive measurement were performed using one-way ANOVA with post hoc Tukey HSD test or Kruskal-Wallis test according to the data normality. An intraclass correlation coefficient among the various methods and their 95% confident intervals were calculated and the agreement was evaluated by using Bland-Altman plot with 95% limits of agreement of the differences. Results Spot photoscreener underestimated spherical equivalent of 2.33D in these infants. With induction of cycloplegia, spherical equivalent measured by Spot photoscreener were in excellent agreement with cycloplegic retinoscopy with the mean difference of 0.01D. Spot photoscreener overestimated cylindrical parameter of 0.2D with poor agreements with cycloplegic retinoscopy no matter whether cycloplegia was induced. It had much more reliable measurement in J 0 vector than J 45 vector measurement. Conclusions With induction of the cycloplegia, Spot photoscreener accurately evaluates spherical equivalent in young infants. It may provide valuable measurement of astigmatism, but the bias in cyclinder and axis by the Spot photoscreener should be taken into account.