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KMID : 1159320150170020163
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Korean Journal of Vision Science
2015 Volume.17 No. 2 p.163 ~ p.172
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Evaluation of Optical Quality After Orthokeratology Contact Lens Wear
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Kim Hui-June
Lee Koon-Ja
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Abstract
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Purpose: To investigate the pre-operative and post-operative objective optical quality after overnight orthokeratology (ortho-k).
Methods: Forty five patients (85 eyes) satisfying the inclusion criteria (myopia < -6.00 D, astigmatism < -2.00 D, K-reading: 40.00~47.50 D) were participated for overnight ortho-k. Refraction was performed using auto-refractormeter, and visual acuity was measured using the LCD Chart ETDRS. Objective optical quality measurements were performed using the OQAS (Optical Quality Analysis System II) for MTF (modulation transfer function), Strehl ratio, and OSI (objective scattering index) and OVs (OQAS values) ; OV100%, OV20%, OV9% were measured. Before ortho-k all optical quality measurements were performed after calibration with trial spectacle lenses for the spherical cylindrical correction. Statistical analyses were performed with SPSS 18.0 and p-value less than 0.05 was considered statistically significant.
Results: The VA were significantly increased with 0.79±0.24 logMAR, and 0.03±0.05 logMAR at pre, and post 1 month operation (p<0.001). OV100% and OV20% were not difference however, OV9% was significantly decreased. difference in comparison with corrected pre-operative VA (p=0.011). The MTF values Strehl ratio were significantly decreased (p<0.05) and OSI value were significantly increased (p<0.05) after ortho-K.
Conclusion: VA was significantly improved and the MTF cutoff and strehl ratio and OSI values were in the normal criteria, after ortho-k however, visual quality is decreased and low contrast objective VA was decreased compared with spectacle lens correction.
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KEYWORD
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ortho-k, MTF cutoff, OSI, Strehl ratio, OQAS value
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