Abstract

DO.25.09

Optical ray tracing

Michael Mrochen1,2, Hans Peter Iseli2,3, Theo Seiler2,4, Tobias Koller2
1Eidgenössische Technische Hochschule, Zürich, Schweiz; 2IROC – Insitut für Refraktive und Ophthalmochirurgie, Zürich, Schweiz, 3Augenklinik, Universitätsklinikum Leipzig, Leipzig, Deutschland; 4Universitätsklinik Zürich, Zürich, Schweiz

Objective
Optical calculations have shown that wave front based ablation profiles as well as intraocular lens implantations can cause residual aberrations or even induce significant additional aberrations due to the negligence of the eye’s multi-lens structure specifically in eyes that require higher corrections. Only individualized eye models can provide accurate ablation profiles for these cases. The aim of this report is to analyse the relevance of individualized eye models for refractive treatment planning.
Methods
A method for the customization of eye models based on measurement data of a specific patient is presented. Furthermore, the calculation of optimal ablation profiles and IOL shapes by means of ray tracing through customized model eyes are discussed.
Results
Optical ray tracing algorithms enable surgeons to incorporate corneal topography, corneal back surface, biometric data such as corneal thickness (CT), anterior chamber depth (ACD), lens thickness (LT) and ocular length (OL) into their treatment planning. An ideal ablation profile or a customized intra-ocular lens can be calculated based on the obtained individualized eye models.
Conclusions
Optical ray tracing algorithms allow the highest degree of customization. This new method has the potential to overcome the systematic induction of higher order aberrations by means of wave front guided treatments or standard intra-ocular lenses. However, these theoretical observations must be supported by future clinical trials.

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