Comparison of refractive assessment by wavefront aberrometry, autorefraction, and subjective refraction

To compare refractive assessment results obtained with an aberrometer, an autorefractor, and manual subjective refraction (SR) in a healthy population with optimal visual potential.

Sixty adults aged 18-59 years with visual acuity of 20/25 or better, no media opacity, and no known corneal or retinal abnormalities were recruited during the course of routine eye examination. Refractive error in both eyes of each patient was assessed by 3 methods: manual SR, a Nidek 530-A autorefractor (AR), and a Nidek OPD-II Scan wavefront aberrometer (OPD). The order of testing was randomized. One technician collected all OPD and AR measurements, and 1 optometrist performed manual SR. Refractive measurements were converted from spherocylindrical prescriptions to power vectors and compared between methods by 2-factor repeated measures and Bland-Altman analysis.

Analysis of the power vectors followed by a log transformation showed no significant difference in refractive results between AR, OPD, and SR (P=.63). Bland-Altman analysis identified mean differences (95% CI of limits of agreement) of -0.06 (-0.67 to 0.55) for OPD vs SR, 0.001 (-0.522 to 0.524) for AR vs SR, and 0.06 (-0.541 to 0.662) for AR vs OPD.

Agreement between all refractive assessments was comparable to previously reported agreement between repeated measures of SR. Agreement between AR and SR was slightly stronger than between OPD and SR. Although both the OPD and AR results, in general, showed a high level of agreement with SR, results beyond ±0.50D (5.8% for AR, 10% for OPD) would discourage prescribing spectacles directly from either instrument.