Abstract
Purpose :
The aim of this study was to evaluate three methods of calculating objective refraction based on the measured wavefront aberration, with a comparison to subjective refraction. This study aimed to gain a comprehensive understanding of refraction and intended to enhance the estimation of the objective refraction accuracy by taking into account all aberrations.
Methods :
In this study, method 1’s refraction is given by second-order Zernike coefficients of the eye aberration: M1 = C20*4sqrt(3)/R2. Method 2 is calculated by the Zernike expansion of the Seidel formula for defocus: M2 = (C204sqrt(3) - C4012sqrt(5) + C6024sqrt(7))/R2. Method 3, as illustrated in Figure 1, is obtained by optimizing the visual Strehl ratio based on the optical transfer function (VSOTF). The method follows the same procedure for optometrists to measure eye prescriptions. The three methods were applied to 20 bare eyes with the higher order aberrations RMS (root mean square) from low to high. They were compared to the corresponding manifest counterparts.
Results :
In general, the refraction obtained from the three approaches demonstrated reasonably good accuracy in predicting subjective refraction, especially in low RMS scenarios. For patients with medium to high RMS aberrations, M1 and M2 do not always match, but are quite close in many cases for M2. M3 was generally better than the other two methods.
Conclusions :
Objective refraction obtained from this optimal VSOTF approach provides a method that includes all aberrations and also integrates the neural contrast sensitivity function. It demonstrated a relatively high accuracy in the prediction of manifest refraction. All three methods provide similar outcomes, as a result, the method has the potential to match a wide range of manifest refractions.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.