Refractive index redistribution with accommodation based on finite volume-constant age-dependent mechanical modeling

Area of Science:

• Ophthalmology
• Biomedical Optics
• Computational Biology

Background:

• The human lens possesses a gradient refractive index (GRIN) crucial for vision.
• Accurate modeling of age-dependent GRIN changes is essential for understanding visual function.

Purpose of the Study:

• To simulate the human lens accommodation process using an anatomically accurate finite mechanical model.
• To investigate age-related changes in axial and radial GRIN profiles.
• To evaluate the impact of GRIN redistribution on optical performance during accommodation.

Main Methods:

• Utilized the accommodating volume-constant age-dependent optical (AVOCADO) model.
• Employed finite element method (FEM) to simulate lens accommodation and GRIN redistribution.
• Applied ray tracing to assess the optical performance of the modeled lenses.
• Analyzed lenses from 25-, 35-, and 45-year-old individuals.

Main Results:

• Axial GRIN steepness parameter (p) increases with age.
• During accommodation, the axial p value increases, while the radial p value decreases.
• Age-dependent GRIN changes significantly influence the lens's optical properties.

Conclusions:

• The study provides a robust finite mechanical lens model with distinct axial and radial GRIN profiles.
• Findings enhance the understanding of age-related accommodation mechanisms and optical performance.
• The AVOCADO model accurately captures GRIN dynamics, offering insights into presbyopia.