Vector analysis of clinical refractive agreement between autorefraction, retinoscopy, and subjective refraction in non-cycloplegic patients
Keywords:
Ocular refraction, Autorefractometry, Static retinoscopy, Subjective refraction, Thibos vector notation, Refractive concordanceAbstract
Background: Refractive errors are among the leading causes of visual impairment worldwide. In clinical practice, refraction can be determined by objective methods such as autorefraction and static retinoscopy, or by subjective refraction, which is considered the reference standard. The vector notation proposed by Thibos and Horner (M, J0, and J45) provides a more robust comparison between these techniques. Objective: To analyze the clinical refractive agreement among autorefraction, retinoscopy, and subjective refraction in non-cycloplegic patients using vector notation. Material and methods: A cross-sectional study was conducted in 254 patients examined at the Centro Regional de Salud Valencia, University of El Salvador. Right-eye refraction data were obtained using the three methods mentioned. Refractive errors were transformed into vector notation (M, J0, and J45). Variables were expressed as medians and interquartile ranges (IQR). The Kruskal–Wallis test was used to compare methods, the intraclass correlation coefficient (ICC) was used to assess agreement, and Spearman’s correlation was used to determine relationships between vectors. Bland–Altman plots were used to explore systematic biases. Results: The spherical equivalent (M) showed similar medians among methods (p = 0.861) and excellent agreement (ICC = 0.958). The astigmatic vectors (J0, J45) showed good agreement (ICC ≈ 0.88) and greater dispersion. All correlations were statistically significant (p < 0.001). Conclusion: The three methods yielded comparable results, with excellent agreement for M and good agreement for J0 and J45. Autorefraction proved to be a reliable tool for refractive screening in high-demand clinical settings, although subjective refraction remains recommended in cases of significant astigmatism or discrepancies between methods.
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