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Proceedings Paper

Computer simulation of corneal curvature change caused by intrastromal ablations using a pico-second lasersystem
Author(s): H. Hennighausen; Josef F. Bille
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Paper Abstract

In order to predict corneal curvature change after intrastromal surgery three finite element models are developed and compared. The models differ essentially in the underlying assumptions about the mechanical behavior of the cornea. The first model assumes an isotropic corneal structure with a nonlinear stress/strain behavior, thus providing a lower limit for the corneal curvature change. Contrary model two assumes transverse isotropy combined with a linear stress/strain behavior, in order to provide an upper limit for corneal curvature change. Although differing in their structural assumptions, model one and two consider the cornea as being a solid structure. A third model, based on a multilayered thin shell theory, shows that this might not be sufficient. In addition the calculations are run for two different ablation patterns. The performed analyses are extremely useful in choosing ablation patterns and dimensions for intrastromal refractive surgery. But as the model predictions of corneal curvature change differ in about 4 dpt for a given pattern, more subtle modifications and a better knowledge of the mechanical parameters of the cornea are necessary in order to obtain applicability of model calculations to predict the actual outcome of a performed surgery.

Paper Details

Date Published: 12 January 1995
PDF: 9 pages
Proc. SPIE 2330, Lasers in Ophthalmology II, (12 January 1995); doi: 10.1117/12.199253
Show Author Affiliations
H. Hennighausen, Univ. of Heidelberg (Germany)
Josef F. Bille, Univ. of Heidelberg (Germany)

Published in SPIE Proceedings Vol. 2330:
Lasers in Ophthalmology II
Rosario Brancato; Adolf Friedrich Fercher; Pascal O. Rol; A. S. Melamed, Editor(s)

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