Accuracy and Efficiency of Refraction for Myopes Based on the Visual Adaptive Optics Simulator

Objective: This study aimed to evaluate the accuracy and efficiency of the Visual Adaptive Optics Simulator (VAO, Spain) which is able to measure objective and subjective refraction. Methods: The refractor VAO was an instrument based on the principle of adaptive optics. This was a series case study that included patients in Changsha Aier Eye Hospital from October to November 2017. Subjects with myopia were first measured by experienced optometrists for objective and subjective refraction using an autorefractor (Nidek ARK-1) and phoropter, respectively (designated as the "traditional approach"). Then, these subjects were again measured by a fresh technician with the VAO-based approach. The agreement of the results by these two approaches was compared with an intraclass correlation coefficient (ICC) and a paired-t test analysis. The efficiency of the VAO-based approach was also compared to the traditional approach with a paired-t test. Results: Seventy subjects (140 eyes, 38 males) with a mean age of 13.2±2.2 years participated in the study. The ICC of the objective refraction between the two approaches was 0.897, 0.907, 0.732 for spherical power, J0 and J45, respectively. The ICC of subjective refraction between the two approaches was 0.937, 0.891, 0.543, respectively. Specifically, the mean difference in objective and subjective refraction for spherical power with the two approaches was 0.46 D (95%CI: 0.36, 0.55 D) (t=9.663, P<0.001), and 0.32 D (95%CI: 0.25, 0.39 D) (t=9.087, P<0.001). However, the difference was found to diminish with an increase in the degree of myopia (r=-0.261, P<0.001) and the difference inspherical power dropped by 0.22 D [0.14 D, 0.32 D] for moderate-high myopia (spherical power <-3.00 D; t=4.987, P<0.001). For cylindrical power, there was no significant difference between the two approaches. Never the less, the average measurement time for the VAO-based approach was found to be significantly shorter than the traditional approach (5.9±1.9 min vs. 7.2±0.7 min, t=6.100, P<0.001). Conclusions: VAO produces clinically similar results compared to the traditional approach and the difference between the two approaches tends to be reduced with a greater degree of myopia. In addition, the efficiency of VAO is significantly better than the traditional approach. Key words: adaptive optics; myopia; refraction