Three-dimensional reconstruction of the corneal surface provides a powerful tool for managing corneal diseases. This study proposes a novel method for reconstructing the corneal surface from elevation point clouds, using modal schemes capable of reproducing corneal shapes using surface polynomial functions. The multivariable polynomial fitting was performed using a non-dominated sorting multivariable genetic algorithm (NS-MVGA). Standard reconstruction methods using least-squares discrete fitting (LSQ) and sequential quadratic programming (SQP) were compared with the evolutionary algorithm-based approach. The study included 270 corneal surfaces of 135 eyes of 102 patients (ages 11–63) sorted in two groups: control (66 eyes of 33 patients) and keratoconus (KC) (69 eyes of 69 patients). Tomographic information (Sirius, Costruzione Strumenti Oftalmici, Italy) was processed using Matlab. The goodness of fit for each method was evaluated using mean squared error (MSE), measured at the same nodes where the elevation data were collected. Polynomial fitting based on NS-MVGA improves MSE values by 86% compared to LSQ-based methods in healthy patients. Moreover, this new method improves aberrated surface reconstruction by an average value of 56% if compared with LSQ-based methods in keratoconus patients. Finally, significant improvements were also found in morpho-geometric parameters, such as asphericity and corneal curvature radii.
Gait is influenced by many factors, but one of the most prominent ones is shoe heel height. Optical motion tracking technology is widely used to analyze high-heeled gait, but it normally involves several high-quality cameras and licensed software, so clinics and researchers with low budgets cannot afford them. This article presents a simple, effective technique to measure the rotation angles on the sagittal plane of the ankle (tibiotalar) and toe (metatarsophalangeal) joints when no shoes (0 cm heel) and high-heeled shoes (2, 6 and 10 cm heels) are worn. The foot’s position was determined by a set of equations based on its geometry and video analysis techniques with free software (Tracker). An evaluation of the spatio-temporal variables confirmed observations from previous studies: increasing heel heights reduces gait cycle length and speed but does not change cadence. The range of movement at the tibiotalar joint progressively narrowed from 28° when no heel height was worn to 9° when a 10 cm heel was used, and these reductions ranged from 30° to 5° for metatarsophalangeal joints, respectively. This aligns with other authors’ previous studies, and confirms that the proposed method accurately measures kinematic ankle–foot set changes when wearing high heels.