Effect of gradient-index lenses on the optical performance of SyntEyes

This study analyzes the effect of two different gradient index (GRIN) crystalline lens models on ocular optical performance compared to that of a homogeneous lens. Using the biometric data of 200 SyntEyes (synthetically generated eyes), we implemented three lens models: homogeneous, GRIN, and GRINCU (gradient index and gradient curvature of the isoindicial surfaces). Using the three lens models, we conducted finite ray tracing on the SyntEyes samples, incorporating five different curvature gradients into the GRINCU setup. We calculated the average cardinal points and Zernike aberration coefficients for each SyntEyes sample, along with the cardinal points for each lens model. GRINCU lens configurations with increased IIS curvature toward the center result in an average forward shift of the lens principal planes, leading to increased ocular power relative to the homogeneous lens model. Steeper curvature gradients of the IIS towards the lens center result in reduced astigmatism, defocus, lateral coma, and primary spherical aberration. The interplay between the lens's gradient index and IIS curvature gradient alters the optical properties of the eye as a whole, highlighting the crucial role of the lens's internal properties in optical performance.