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KMID : 1159320150170020142
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Korean Journal of Vision Science
2015 Volume.17 No. 2 p.142 ~ p.150
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Evaluation of Objective Visual Acuity Measured by the Double-Pass Technique in Corneal Refractive Surgery Patients
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Kim Jeong-Mee
Lee Koon-Ja
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Abstract
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Purpose: To compare the objective visual acuity of corneal refractive surgery patients with emmetropes by using a double-pass instrument.
Methods: One hundred thirty five eyes of 68 subjects (23.49±2.5 years) who underwent myopic refractive surgery and 40 eyes of 20 emmetropes (22.50±1.7 years) were enrolled. High and low contrast visual acuity (HCVA and LCVA) using ETDRS charts were measured under photopic and mesopic conditions. Objective OVs (OQAS values) and objective VA (visual acuity), respectively, at contrasts of 100%, 20%, and 9% as an optical quality parameter were measured by the OQAS (optical quality analysis system).
Results: There was no difference in subjective HCVA and LCVA under photopic condition between the emmetropic and post-op groups, however, there was statistically difference in HCVA and LCVA under mesopic condition between two groups (p=0.027, p=0.002, respectively). There were significant differences in OVs measured by OQAS between two groups (p=0.012, p=0.003, p=0.001, respectively), and objective VAs in the post-op group decreased more with the low contrasts and were correlated with subjective VA (p<0.05), LCVA under mesopic condition and VA 9% were highly correlated (R=-0.403).
Conclusion: In the post-op group, objective visual acuity measured by OQAS was lower than that compared with emmetropes, especially, visual acuity in the post-op group decreased more compared to emmetropes at low contrast conditions.
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KEYWORD
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Corneal refractive surgery, Double-pass technique, Optical quality, Visual acuity
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