Comparison of Peripheral Refractions Determined by Different Instruments


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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° 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.

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