J. Eur. Opt. Society-Rapid Publ. 21, 10( 2025) 101
Figure 8.( a) illustrate the correlation between the intended and estimated LPs.( b) displays the different geometries( 23 data points) versus the intended LPs annotated with the estimated LPs. Myopic corrections were intended. Minor corrections associate with the larger planned diameters, and vice versa.
Figure
9.( b) identifies the transition zones of( a), as the regions within the posterior fit curvature alters from convex to concave corresponding to a sign change of the 2nd order gradient.( c) illustrate the hinge angle detection( on flap cuts) using a similar rationale. The black dashed lines illustrate ~ A and ~ B to determine h.
an angle of 150 ° across 10 flap cuts, resulting in a total deviation of 15 °.
Moreover, full 2D segmentations would facilitate the application of 3D analysis such as determination of Keratometry reading or analysis of anterior aberrations [ 68, 69 ].
Despite the potential influence of factors such as hydration on the peri-operative eyes, the analysis demonstrated a high correlation between intended and automatically measured values. It might suggest that ambient conditions did not significantly alter the morphologies.
Figure 10 provides a summary of the linear regression analysis for the estimations of FD, FT, LD, and LT. The proposed approach estimates flap and lenticule diameters, as well as thicknesses, without additional computational overhead. The regression analysis indicates that the estimations on flap cuts show a stronger correlation with their intended values compared to lenticule cuts. Specifically, the estimated flap thicknesses( FTs) exhibit the smallest discrepancies from the intended values. The lenticule characteristics generally demonstrate greater deviations. Notably, the highest deviation is observed in the subgroup with an intended lenticule thickness( LT) of 150 lm. This deviation from regression might originate from the statistically insufficient sample size. A larger sample size may better determine if measured lenticule thicknesses will be consistently larger than intended values. It was found that the measured LT was significantly greater than the intended LT. This discrepancy was observed in the overall scheme rather than a specific thickness range [ 15 ].
The estimated LD values are approximately 0.8 mm smaller than the intended values( Fig. 10c). These discrepancies can be partially attributed to the BO that numerically compresses the posterior peaks. In the absence of an optimization routine, these values could significantly deviate towards much larger values. Thus, a scope of future work would integrate the performance of versatile optimization approaches to figure out the best combination for posterior characterization. Additionally, associated difficulties to determine transition zone within LD can potentially contribute to the observed discrepancies. Moreover, the estimations( or even manual measurements) were performed ex vivo on porcine eyes unlike human living subjects which also can trigger shorter estimations than planned [ 49 ]. Complementarily, Figure 10a illustrates that the estimated values of FD lag behind the intended values, approximately 0.5 mm. The discrepancies can root to a probable combination of edge compression by the BO and ex vivo measurements.