The aim of this study was to estimate the agreement between an autorefractor (Nidek ARK 700A, Gamagori, Japan) and retinoscopy with subjective refraction.
Measurements of autorefraction obtained with the ARK700A and retinoscopy were performed on 192 right eyes from 192 healthy young adults and compared with subjective refraction. These measurements were performed without cycloplegia. The age range was 18 to 34 years, with a mean value of 21.6 years and an SD of 2.66 years.
A comparison of the autorefractor and subjective refraction results shows that (1) for the mean spherical equivalent (M), the autorefractor yields more negative values (−0.44 ± 0.54 D; p = 0.000); (2) for the Jackson cross-cylinder at axis 0° (J0), the autorefractor yields more positive values than the subjective ones (0.05 ± 0.13 D; p = 0.000); and (3) for the Jackson cross-cylinder at axis 45° (J45), the autorefractor results are more negative (−0.02 ± 0.09 D; p = 0.019). The differences found for each component M, J0, and J45 are statistically significant. By comparing retinoscopy with the subjective examination, there are no statistically significant differences found for the M component (−0.02 ± 0.33 D; p = 0.304). For the J0 and J45 components, the differences are statistically significant (0.07 ± 0.10 D, p = 0.000; −0.01 ± 0.08 D, p = 0.008).
The present results confirm that when performed by an experienced clinician, retinoscopy is more accurate than automatic refraction, giving a better starting point to noncycloplegic refraction.
Department of Physics (Optometry), School of Sciences, University of Minho, Braga, Portugal (JJ, AQ, JBA), and Department of Surgery (Ophthalmology), School of Optics and Optometry, University of Santiago de Compostela, Spain (MAP)
Received February 15, 2004; accepted October 5, 2004.