Agreement evaluation between adaptive optics visual simulator and conventional refraction methods

Objective

To evaluate the difference and agreement of cycloplegic refraction between adaptive optics visual simulator (VAO) and conventional refraction methods.

Methods

A diagnostic test study was conducted.Thirty-one eyes of 31 healthy subjects including 15 males and 16 females were enrolled in November, 2019 in Affiliated Hospital of North Sichuan Medical College.Mean age of the subjects was (20.1±1.0) years, and the right eye was taken for data analysis.Cycloplegic refraction was measured by VAO and conventional refraction methods, respectively.Spherical power, cylindrical power, Jackson cross-cylinder power at axis 90° and 180° (J₀) and Jackson cross-cylinder power at axis 45° and 135° (J₄₅) vector powers were recorded.Paired t-test was used to compare the refractive parameters between different refraction methods, and the intraclass correlation coefficient (ICC) and Bland-Altman plots were used to evaluate the agreement between VAO and conventional refraction methods.This study adhered to the Declaration of Helsinki, and the research protocal was approved by an Ethics Committee of Affiliated Hospital of North Sichuan Medical College (No.2020ER[A]018). Written informed consent was obtained from each subject prior to any medical examination.

Results

For subjective refraction, the ICC for spherical power, cylindrical power, J₀ and J₄₅ between VAO and phoropter were 0.97, 0.75, 0.84 and 0.09, respectively.For objective refraction, the ICC for spherical power, cylindrical power, J₀ and J₄₅ between VAO and autorefractor were 0.98, 0.70, 0.74 and 0.61, respectively.The mean differences in spherical power, cylindrical power, J₀ and J₄₅ between VAO and phoropter were (0.05±0.32), (-0.23±0.28), (-0.10±0.14) and (-0.04±0.16)D, respectively, and the differences in cylindrical power and J₀ were statistically significant (both at P<0.01), whereas no significant differences in spherical power and J₄₅ were found (P=0.41, 0.18). The mean differences in spherical power, cylindrical power, J₀ and J₄₅ measured by VAO and autorefractor were (-0.70±0.26), (-0.07±0.46), (-0.03±0.27) and (0.01±0.12)D, respectively, and the spherical power measurement by VAO was significantly more negative than the autorefractor (t=15.09, P<0.01), while no significant differences in cylindrical power, J₀ and J₄₅ were found (P=0.39, 0.59, 0.63). No significant difference values in spherical power, cylindrical power, J₀ and J₄₅ were found between the two objective refraction methods and phoropter subjective refraction (all at P>0.05).

Conclusions

With cycloplegia, spherical power obtained by VAO objective refraction is more negative compared with autorefractor.There is a good agreement of spherical power and astigmatism vector values measured by VAO and phoropter subjective refraction, and the measurement differences are clinically acceptable.