• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.433-438
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• 2011

Purpose: To investigate the proper distance from patient to target when measuring refractive error using open view target type auto-refractor(OVTAR), it was compared refractive errors between by OVTAR using N-vision-K5001 auto-refractor and internal fixation target type auto-refractor(IFTAR) using Canon auto-refractor. Methods: 21 subjects(42 eyes) aged 22.2(${\pm}$3.4) years old who had over 1.0 of corrected visual acuity and no ocular disease were participated for this study. Noncycloplegic measurements of refractive error were performed using a IFTAR(RK-F1, Canon, Japan) and an OVTAR(N-vision-K5001, Shin-nippon, Japan). The distances from subjects to targets in using the open the view target type auto-refractor were 1 m, 3 m, 4 m and 6 m. The refractive errors were compared between by IFTAR and by 1 m, 3 m, 4 m and 6 m target distances respectively using OVTAR. Results: At 1 m fixation distance the mean of refractive errors for total subjects was not significantly different between by OVTAR(-2.75${\pm}$1.84 D) and by IFTAR(-2.95${\pm}$2.04 D)(p=0.06). However at 3, 4 and 6 m fixation distance refractive errors by OVTAR were significantly lower myopic refractive errors than by IFTAR(p<0.05). Conclusions: The distance from subject to fixation target is needed over 3 m for the measurement of refractive error using OVTAR even not to 5~6 m distance.