Mechanics of accommodation of the human eye

The classical Helmholtz theory of accommodation has, over the years, not go ne unchallenged and most recently has been opposed by Schachar at al. (1993 ) (Annals of Ophthalmology, 25 (1) 5-9) who suggest that increasing the zon ular tension increases rather than decreases the power of the lens. This vi ew is supported by a numerical analysis of the lens based on a linearised f orm of the governing equations. We propose in this paper an alternative num erical model in which the geometric non-linear behaviour of the lens is exp licitly included. Our results differ from those of Schachar et al. (1993) a nd are consistent with the classical Helmholtz mechanism. (C) 1999 Elsevier Science Ltd. All rights reserved.