The optical characteristics of the peripheral field of view are closely related to the onset and progression of myopia. Accurate measurement of peripheral field aberrations is thus crucial for myopia prevention and control. When using the Shack-Hartmann (SH) wavefront sensor to measure peripheral aberrations in the human eye, two key challenges must be addressed to ensure data accuracy: elliptic pupil processing and phase unwrapping. Currently, three elliptic pupil processing algorithms are available: large circle pupil (LC), small circle pupil (SC), and stretched ellipse pupil (SE) methods. However, their ability to produce Zernike coefficients that align with the true wavefront remains unstudied—this is a significant clinical concern. Therefore, one objective of this paper is to identify the algorithm most consistent with actual wavefront aberrations. In addition, to overcome the limitations of edge point loss in the sequential phase unwrapping algorithm, we propose an edge point screening method that automates sequential unwrapping, replacing the manual removal techniques commonly used in prior studies.

To minimize errors caused by experimental measurements, a wide-field aberration measurement system for the human eye, based on the SH sensor, is constructed using Zemax’s non-sequential mode (Fig. 1). Spot images generated by the SH wavefront sensor under horizontal fields of view of 0°, 10°, 20°, and 30° are collected. A wide-field wavefront reconstruction data processing program is developed in MATLAB, using these spot images as input. Zernike coefficients are then calculated using three elliptic pupil processing methods: LC, SC, and SE. The wavefront aberration at the exit pupil of the eye model, representing the true wavefront aberration of the human eye model, is extracted in serial mode. By calculating the root mean square error (RMSE), spherical equivalence M, horizontal astigmatism J0, and point spread function (PSF) of the reconstructed wavefronts, the differences between the three elliptic pupil processing methods, and the true wavefront aberration are quantitatively compared. For unwrapping, an edge screening method is proposed to pair point fields with the sequence one by one. The program is written in MATLAB.

The differences between defocus (Z4), astigmatism (Z5), and spherical aberration (Z12) coefficients and the real wavefront aberration under a 0° field of view are 0.132, 0.003, and 0.008 μm, respectively (Table 1), demonstrating the reliability of the system modeling and wavefront reconstruction algorithm. The validity of the edge-screening method, based on ranking methods for the unwrapping algorithm, is confirmed by obtaining consistent results with previous studies. The differences between Zernike coefficients reconstructed by the three methods and the real wavefront are compared under 10° and 30° fields of view. No significant differences are observed in the small field of view, while discrepancies begin to emerge in larger fields of view (Fig. 7). Quantitative analysis of the RMSE, M, and J0 (Table 3) further support these findings. At the 10° field of view, the residual error of the SC method is as low as 1.958%, indicating the most accurate reconstruction. At a 30° field of view, the residual error of the SC method is 4.717%, making it the closest to the real wavefront. Clinically, similar trends are observed: no significant differences in M and J0 among the three methods at 10° field of view; however, at the 30° field of view, the LC and SC methods show significant differences in M, while the J0 values remain consistent, with the SE method yielding the smallest deviation from the real wavefront. To further characterize the visual influence of wavefront aberrations, PSF images are generated using Zernike coefficients from the three methods and are compared with PSF images derived from the true wavefront. Under a small field of view, the PSF images closely match the real PSF, with minor edge deformation observed in the SE method. At larger fields of view, the PSF images from the SE and LC methods exhibit no significant differences from the PSF obtained from the true wavefront aberrations, while the SC method shows noticeable data loss.

In a small field of view, all three methods—LC, SC, and SE—produce wavefront aberrations consistent with the true aberrations. However, the SE method introduces an additional, irreversible stretching effect on the PSF. Therefore, the SC method is the preferred choice for constructing wavefront aberrations in this context, given its simplicity and ease of implementation. For larger fields of view, the SE method is the optimal choice due to its superior accuracy in providing reliable wavefront estimations. The improvement brought by the edge screening method in the sequential spot location method is considerable.