Comparison of peripheral refractions determined by different instruments

Abstract

PURPOSE: To compare peripheral refractions obtained with a Hartmann-Shack sensor instrument and two commercial autorefractors. METHODS: Measurements were taken with a laboratory Hartmann-Shack instrument, the Canon Autoref R-1, and the Shin-Nippon SRW-5000 to 40 degrees in both directions along the horizontal meridian. RESULTS: The agreement between the Hartmann-Shack instrument and the Shin-Nippon autorefractor was good, with mean power differences varying from 0.3 D at the center of the visual field to 0.7 D at the edge of the visual field. The agreement between the Hartmann-Shack and Canon Autoref R-1 was not as good, but neither was the agreement between the Shin-Nippon and Canon instruments. CONCLUSIONS: The agreement between the instruments was similar to other comparisons made between different techniques. Combined with the high magnitude of peripheral refractions, this indicates that the Hartmann-Shack sensor technique can validly be extended from measuring central refractions to measuring peripheral refractions.