Abstract
Abstract: The human crystalline lens has long been known for its gradient index of refraction (GRIN) due to the varying protein content of crystalline. The classic Gullstrand schematic eye has treated the crystalline lens as a homogenous optical element, which accurately model the first order optics but not the higher order aberrations. Researchers had proposed several eye models that include a crystalline lens with gradient index of refraction incorporated. They used a polynomial representation of the GRIN profile up to the second order coefficients. Three existing models have been simulated using the lens design program CODE V in our comparative study that first order optics and higher order aberrations are both analyzed. It's shown that by modifying the GRIN polynomial coefficients up to the second order the focal length of the crystalline lens and thus the optical power of the eye could be changed similar to the result of natural accommodation but without changing the lens shape, which is a possible way of introducing accommodation in intraocular lenses (IOL). In addition higher order coefficients are added to the GRIN profile representation to evaluate the optical aberrations of the crystalline lens such as spherical aberration and chromatic aberration, which may provide an explanation to the phenomena of lens spherical aberration compensation to the cornea and its little contribution to the total eye chromatic aberration.