Comparison of Different Types of Objective Auto Refractors with Subjective Refraction

Abstract

Purpose : The purpose of this study was to compare results from three different types of autorefractor including open-view, closed-view and hand-held type with subjective refraction. Methods : One hundred students (the mean age of 25.2±1.63) underwent objective refraction using three types of autorefractor including open-fied, closed type and hand-held type (Nvision-k 5001P, KR-8100P and Righton Retinomax K-plus). Subjective refraction for all was performed by an experienced optometrist without reference of autorefractors’ results. The difference of results between three autorefractors and subjective refraction was compared. Results : With the result of subjective refraction, the difference was shown minimum with open-view autorefractor followed by closed-view and hand-held autorefractor, which is significant difference among the devices (p<0.001). In addition, there was significant difference between subjective and objective refractions in spherical equivalent. The difference was minimum with open-view autorefractor followed by closed-view and hand-held autorefractor (p<0.001). Conclusion : The difference between open-view and closed-view type of autorefractor was not significant. Therefore, the results from these devices would be a good reference for subjective refraction. However, attention needs to be taken for held-held type as it may stimulate accommodation or cause measurement error.