Abstract
Purpose
To compare the accuracy of myopic refraction using an aberrometer (WaveScan, Visx, Santa Clara, CA, USA) with manifest refraction using retinoscopy and an autorefractor.
Methods
The medical records of 200 eyes in 100 patients who visited our clinic from February 2005 to February 2007 for refractive surgery were reviewed retrospectively. We compared the refractive errors obtained using an aberrometer, retinoscopy, and an autorefractor (KR-7100, Topcon, Tokyo, Japan). All of the measured refractive errors were converted to power vectors for statistical analysis. The power vectors consisted of the M vector (M), J0 vector (J0), and J45 vector (J45).
Results
The mean sphere was −4.75 diopters (D) and the mean cylinder was −0.66D with retinoscopy. Power vectors of the aberrometer (PVw) were highly correlated with power vectors of retinoscopy (PVr) and the autrorefractor (PVa). The correlation coefficients (R2) between PVw and PVr were 0.960 (M), 0.852 (J0), and 0.679 (J45) and the correlation coefficients between PVw and PVr were 0.963 (M), 0.685 (J0), and 0.516 (J45). Mean differences were −0.247±0.412D (M), 0.034±0.120D (J0), and −0.017±1.07D (J45) between PVw and PVr, and were –0.068±0.403D (M), −0.055±0.194D (J0), and −0.052±0.165D (J45) between PVw and PVa.
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Table 1.
Best corrected visual acuity of patients
Visual acuity | Number | Percent | Cumulative percent |
---|---|---|---|
20/12.5 | 30 | 15% | 14% |
20/16 | 141 | 70.5% | 85.5% |
20/20 | 29 | 14.5% | 100% |
Table 2.!
Descriptive statistics of vector analysis
| WaveScan (D) | Manifest refraction (D) | Autorefraction (D) |
---|---|---|---|
M vector | −5.00±2.07 | −4.75±2.04 | −4.93±2.11 |
J0 vector | 0.266±0.310 | 0.232±0.297 | 0.320±0.343 |
J45 vector | −0.028±0.190 | −0.012±0.165 | 0.024±0.237 |
Table 3.
Linear regression statistics with the vectors of the WaveScan
Table 4.
Difference of the vectors between the instruments