Optimizing Visual Performance: Restoring Dynamic Focus Through Biomechanics

This study employs Computer-Aided Design (CAD) modeling to investigate the biomechanical role of the Bruch’s Membrane Choroid Complex (BMCC) in modulating the Dynamic Range of Focus (DRoF) during accommodation and disaccommodation. While accommodation has been widely studied, disaccommodation remains underexplored. This research highlights how the BMCC influences lens dynamics, contributing to a deeper understanding of age-related changes in visual performance and potential strategies for presbyopia intervention. 

This study was conducted using virtual simulation through CAD-based modeling to illustrate the biomechanical forces acting on the crystalline lens and ciliary structures. Computational software embedded images from a literary review on accommodative anatomical and biomechanical movements were analyzed. 

A CAD model was developed to simulate crystalline lens movements across three phases: (1) pre-stretch of the lens, (2) accommodation, and (3) disaccommodation. The model illustrated biomechanical forces, highlighting the elastic properties of the BMCC and its role in lens shape modulation. The BMCC’s interactions with the ciliary muscle, zonules, and posterior ciliary tendons were analyzed to quantify its contribution to the energy transfer mechanisms involved in focus adjustments. Additionally, the model simulated age-related changes in BMCC elasticity, assessing their impact on lens dynamics and DRoF. 

The Computer Animated Model of Accommodation (CAMA) allowed for biomechanical observation of the process of accommodation and disaccommodation.  BMCC’s elastic fibers influence zonular tension and lens flattening during disaccommodation. As the ciliary muscle relaxes, zonular tension increases, flattening the lens for distance focus. During accommodation, the BMCC stores elastic potential energy, altering lens curvature for near vision. Age-related BMCC stiffening weakens its role in disaccommodation, causing a decline in DRoF. This disrupts kinetic and potential energy transfer, reducing the eye’s ability to refocus dynamically. Simulations suggest BMCC elasticity loss contributes to presbyopia, impairing disaccommodation efficiency. 

While research has primarily focused on accommodation, this study emphasizes the critical role of disaccommodation in visual performance. The elastic properties of the BMCC, particularly its connections to the posterior ciliary tendons, serve as key mediators of energy transfer in the DRoF system. Age-related BMCC stiffening contributes to presbyopia by impairing disaccommodation, highlighting new potential targets for presbyopia treatments. Understanding these biomechanical mechanisms provides valuable insight for interventions aimed at rejuvenating DRoF, ultimately improving visual performance in aging populations.