Refractive outcomes of table-mounted and hand-held auto-refractometers

Abstract

BACKGROUND: The purpose of this study was to compare the concordance of measurements between a table-mounted automatic auto-refractor and a portable manual auto-refractor, test the variability of inter-operator measurements, and determine the effect of the head’s position on the measurements. MATERIAL AND METHODS: A prospective study was carried out on 100 healthy eyes. Refraction was acquired with a Topcon RM-800 tabletop auto-refractometer and a Nidek HandyRef K portable auto-refractometer. The refractive errors were compared in terms of the sphere’s power, the cylinder and its axis, the spherical equivalent, and the coordinates of the astigmatism power vectors J0 and J45. Statistical analysis was performed using SPSS software version 20. RESULTS: The average age was 31, with 3 and 71 years old extremes. Fifty-six patients were female (56%), and 52% were right eyes. No difference between the 2 devices concerning the sphere (p = 0.09), the cylinder (p = 0.18), and the spherical equivalent (p = 0.15) was observed. However, there is an average difference of 4° in the astigmatism axis (p ≤ 0.001), which is insignificant if we consider the Jackson power vector J0 (p = 0.24) and J45 (p = 0.85). The position of the head tilted back does not modify the measurements with the portable refractometer. In addition, the HandyRef can be used by any unqualified person with no risk of altering the results of the measurements. CONCLUSION: Our results show a good concordance between the measurements obtained by the two devices. They can therefore be used interchangeably.