The Shack–Hartmann wavefront sensor (SHWFS) is widely utilized for ocular aberration measurement. However, large ocular aberrations caused by individual differences can easily make the spot move out of the range of the corresponding sub-aperture in SHWFS, rendering the traditional centroiding method ineffective. This study applied a novel convolutional neural network (CNN) model to wavefront sensing for large dynamic ocular aberration measurement. The simulation results demonstrate that, compared to the modal method, the dynamic range of our method for main low-order aberrations in ocular system is increased by 1.86 to 43.88 times in variety. Meanwhile, the proposed method also has the best measurement accuracy, and the statistical root mean square (RMS) of the residual wavefronts is 0.0082 ± 0.0185 $\lambda$ (mean ± standard deviation). The proposed method generally has a higher accuracy while having a similar or even better dynamic range as compared to traditional large-dynamic schemes. On the other hand, compared with recently developed deep learning methods, the proposed method has a much larger dynamic range and better measurement accuracy.

To investigate the effect of intraocular scatter on stereopsis, we measured stereoacuity with scatter either remaining at the natural eye-induced level or further enhanced by a set of three different scatter filters. Stereo thresholds at different viewing durations were obtained using a psychophysical method of constant stimuli. The results indicate that stereoacuity was degraded with a binocular increase in scatter levels for all the subjects. Measurements were also performed in the presence of interocular differences in scatter levels. In this case, stereoacuity was found to be even a little worse than that obtained with both eyes at a higher scatter level. This suggests that stereoacuity in the presence of interocular differences in scatter levels is mainly dependent on the higher scatter level.

The measurement of the double-pass (DP) point spread function (PSF) provides an objective, non-invasive method for estimating intraocular scatter in the human eye. In this paper, we propose a compact double-pass objective intraocular scatter measurement system that eliminates the influence of aberrations. The system includes a far-field DP PSF detection channel and a Shack-Hartmann wavefront aberration detection channel, which are used to obtain the far-field DP PSF image and 7 orders Zernike aberration coefficients, respectively. The far-field DP PSF image is used to calculate the initial objective scatter index of the human eye. The aberration coefficients are used to reconstruct the DP PSF image caused by aberrations and calculate the influence coefficient of aberrations on intraocular scatter. By subtracting this influence coefficient from the initial objective scatter index (OSI0), the effect of aberrations on scatter measurement can be eliminated, resulting in an accurate objective scatter coefficient. Experimental verification showed that when the exit pupil aperture of this system was set to 4 mm and 6 mm, the measurement accuracy increased by at least 11.9% and 28.9%, respectively, compared to before eliminating the influence of aberrations. While improving the measurement accuracy, the system also keeps the device size and manufacturing costs at a low level, making it more suitable for clinical applications.

The purpose of this study was to investigate, through theoretical modeling and experiment, the effect of chromatic aberration (CA) on white-light contrast sensitivity (CS) when higher-order aberrations (HOAs) are corrected in the human eye in screen-based vision. Monochromatic aberrations and CA were measured in 10 subjects with normal color vision using an adaptive optics vision simulator (AOVS) under 6 mm pupil diameter. The modulation transfer function (MTF) was calculated for 6 conditions: with and without HOAs under monochromatic red, monochromatic green, and white-light, using 519 nm green light as the best-focus reference. Subsequently, white-light CS was measured under three best-focus conditions and green-light CS was measured under the green-light best-focus condition, both before and after HOAs correction. The presence of HOAs significantly improved the MTF under both green and white illumination in the presence of CA. Furthermore, the MTFs were approximately constant across red, green, and white-light conditions when HOAs were included. Under three best-focus conditions, white-light logCS demonstrated a significant decline following HOAs correction (P < 0.01). Under green-light best-focus condition, green-light logCS demonstrated a significant improvement following HOAs correction (P = 0.001). The results indicate that the presence of CA in the human eye can influence the outcomes of HOAs correction in screen-based vision. Prior to implementing only HOAs correction in clinical practice, it is necessary to evaluate the effect of CA varying with individuals using an AOVS. This research bridges the gap between optical theory and clinical practice, thereby guiding the refinement of wavefront-guided surgeries and personalized intraocular lenses.

Purpose： To investigate whether intraocular scatter introduced by refractive surgery will induce high-order aberrations (HOAs). Method： Intraocular scatter and HOAs (measured at a pupil diameter of 5mm) of 130 myopic eyes (67 patients) were analyzed and compared before surgery and at 1 week, 6 and 12 months after surgery, while 40 normal eyes were set as a control group. Autocorrelation analysis of intraocular scatter and HOAs were performed to confirm the variation trend of ocular scatter and HOAs, respectively. The causal relationship (based on eight criteria: temporal order, strength of association, correlation, exclusion of other explanations, reproducibility, evidence from experimental studies, biological plausibility, and specificity) between intraocular scatter changes and HOAs was analyzed. Result： Intraocular scatter significantly increased during the refractive surgery and then gradually decreased. HOAs decrease slightly during the refractive surgery, and then gradually increased. The results about the causal relationship analysis: (1) There was a significant correlation between the changes of intraocular scatter during refractive surgery and the HOAs at 6 months after refractive surgery (correspond to the temporal order and correlation). (2) The correlations were also found between the changes of intraocular scatter at 6 months after refractive surgery and HOAs at 12 months after refractive surgery (correspond to the reproducibility). (3) The strong correlation within the experimental group did not exist in the control group (correspond to the exclusion of other explanations). (4) The proportion of individuals in the experimental and control groups who match the conclusions drawn from the analysis was calculated and used to calculate relative ratio (RR) of 4.769 (99.0% CI: 1.790~12.706). The z-test (z=4.106, p=0.000) indicates a high strength of causal association, and the proportion of matches in the experimental group is 4.769 times that of the control group. (5) The data collected in this study were based on clinical trials, which meet the requirements for evidence from experimental studies. Conclusions： Intraocular scatter introduced by refractive surgery would induce HOAs.