Abstract
Purpose :
To study the optical performance of a 3-dimensional model of the human lens with conicoid surfaces and an adaptive GRINCU internal structure characterized by two gradients (GR): refractive index (IN) and curvature (CU).
Methods :
The GRINCU adaptive model considers the lens a cemented doublet made of anterior and posterior regions, each with a constant negative curvature radius gradient (Q+1)G, where Q is the external surface conic constant and G is the gradient parameter. This 3D model includes the general non-rotationally symmetric case (i.e., lens astigmatism). We also upgraded the previously proposed model with an improved geometrical formulation. Finally, we implement finite ray tracing in commercial optical design software for the lens as two sequential singlets and a singlet lens for cross-checking.
Results :
The optical performance was computed on a 30-year-old lens model [Navarro, 2014]. All the parameters were fixed except the two variables involved in the curvature radius gradient: Q and G. These two variables strongly impact paraxial lens power and higher-order aberrations. Different combinations of (Q+1) and G can either substantially enhance or decrease the lens power. The well-known negative spherical aberration of the lens is associated with hyperbolic curvatures (Q < -1) of the lens surfaces, but it also requires that G < 0. The calculated Zernike astigmatism is proportional to the curvature radii difference between the principal meridians.
Conclusions :
Surface conic constant and inner curvature gradient strongly impact the optical performance of this double gradient general lens model. Results confirm previous findings and provide an improved understanding of lens optics.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.