Validation of aberrometry-based relative peripheral refraction measurements

Purpose: To validate aberrometry-based relative peripheral refraction (RPR) measurements and to examine RPR differences in the nasal and temporal horizontal visual field. Methods: Thirty subjects underwent cycloplegia in the right eye. Ten measurements each were made centrally, 30 degrees nasally on the retina and 30 degrees temporally on the retina using the Complete Ophthalmic Analysis System (COAS) aberrometer and the Grand Seiko WR-5100K autorefractor in random order. A 2-mm COAS analysis diameter was used to approximate the Grand Seiko autorefractor measurement beam diameter. Nasal and temporal RPR were calculated as the difference between the average nasal or temporal spherical equivalent and the average central spherical equivalent. Repeated measures ANOVAs were used to test for significant differences between the RPR readings of each instrument in each retinal location (nasal or temporal) and to examine refractive error in each direction of gaze for both instruments. Results: Central spherical equivalent refractive error as measured by the Grand Seiko autorefractor ranged from +0.63 D to -8.41 D (mean +/- S.D. = -2.63 D +/- 2.05 D). There were no significant differences between the instruments for RPR measurements (p = 0.34). The nasal RPR was significantly more hyperopic than the temporal RPR (mean +/- S.D. = +0.45 D +/- 1.04 D, p = 0.02). Spherical equivalent refractive error in all directions of gaze was more myopic with the COAS than with the Grand Seiko autorefractor (mean +/- S.D. = -0.41 D +/- 0.61 D, p < 0.0001). Conclusions: RPR measurements with the COAS are feasible and equivalent to those made with the Grand Seiko autorefractor. The COAS can be used to simultaneously collect RPR and peripheral aberration data. Nasal and temporal RPR measurements were significantly different in our sample.