A clinical comparison of subjective refraction results between the Humphrey automatic refractor and a standard method of refraction

The purpose of this study was to investigate the accuracy of a subjective refraction through the Humphrey automatic refractor(AR) as compared to results obtained through a standard Reichart phoropter. Forty-four subjects participated, 88 eyes in all. The AR was performed first; then, after two to three minutes to relax, the subject moved into the exam room for the phorometric refraction. Subjects were placed into one of five groups based on the sphere component of their refractive errors. Sphere powers, cylinder powers, cylinder axis and times of procedure were compared. The results show the AR findings to be significantly more minus in the sphere component of the refraction as compared to those through the phoropter. This was the case in the overall data and also four of the five groups. Statistically, the cylinder power determined by the AR was also significantly more minus than the phoropter findings in the overall data and two of the five groups. One group showed a statistically significant difference in cylinder axis though the difference in the overall data was not significant. The time of procedure was clearly on the side of the AR, an average of two and one-half minutes faster than the standard refraction.