Abstract
Purpose: :
To develop a realistic optical model of the aging eye able to reproduce high order aberrations present in the human eye and their changes with age and accommodation.
Methods: :
We consider the corneal surface as a general non-revolution ellipsoid (this includes conicity, toricity, deviations and displacements of its optical axis) plus some deformation modes represented by the coefficients of a Zernike polynomial expansion (only three coefficients are different from zero). The parameters are average values obtained in a previous study. An adaptive model of the GRIN lens, together with this cornea model permits us to include the changes with age and accommodation. No further fitting of the parameters of the model is applied to compute low and high order aberrations, except for the conic constants of the lens surfaces.
Results: :
The model reproduces the average refractive power, astigmatism and the overall high order aberrations (HOA) present in human eyes. The wavefront pattern of this generic eye displays spherical aberration, coma, trefoil, etc. and resembles the appearance of typical wavefronts measured in human eyes. The model also predicts the changes observed in power and HOA with accommodation. To reproduce the effect of aging we needed to assume a change of the conic constants of the lens surfaces towards more negative values, plus some additional decline in optical quality.
Conclusions: :
A realistic non-rotationally symmetric generic eye model, which includes changes with age and accommodation has been proposed, which reproduces the average power, astigmatism and a realistic wavefront. It can be useful to better understand the optics of accommodation and presbyopia.
Keywords: aberrations • aging: visual performance • accomodation