Abstract

Blaker¹ designed an adaptive human eye model with a gradient-index (GRIN) lens for zero and maximally accommodated states. His GRIN profiles were based on spherical corneal and lens surfaces. We present a computer modeled adaptive schematic eye with aspheric corneal and lens surfaces based on anatomical measurements and a GRIN lens. Our algorithm models up to 10 D of accommodation by continuously varying the axial and radial gradient indices; the anterior chamber and lens thicknesses; and the surface radii and conic constants of the lens. Spherical aberration and longitudinal chromatic aberration computed throughout the range of accommodation agree with empirical data. The astigmatic error of the model eye is compared with several empirical studies. Polychromatic MTFs at each level of accommodation and with pupil diameters of 2-8 mm are presented. We found that the NR1 radial gradient coefficient significantly impacts on paraxial power and can correct spherical aberration, the NR2, and NR3 and NR4 terms increase spherical aberration; and axial gradient terms higher than NZ2 have negligible effect on spherical aberration.

© 1991 Optical Society of America