Modelling studies for the assessment of potential treatments for presbyopia

(Funded by Leverhulme Trust and Wellcome Trust)

Dr Stuart Judge, Dr Harvey Burd, Mr Paul Rosen, Mr Geoffrey Wilde

A program of research is underway in the Civil Engineering Research Group at Oxford University on the development of computational modelling procedures to investigate the mechanics of accommodation in the human eye. This work is partly concerned with developing an improved understanding of the natural accommodation process. It is also intended to lead to computational procedures that can be used to investigate the likely effectiveness of proposed treatments for presbyopia (e.g. lens refilling, accommodating IOLs, femtosecond laser treatment of the lens).

Computational studies have been carried out on the mechanics of the lens-refilling process. These studies indicate that it would be possible to restore the ability of presbyopic lenses to accommodate provided that appropriate re-filling material is used and that the volume of material injected into the lens capsule is carefully controlled. There are, of course, other challenges to be faced (such as the tendency of the capsule to stiffen and to become opaque once the lens is removed).

We have also conducted detailed numerical studies of the laser lentotomy process (in which the compliance of the lens is increased by using a femtosecond laser to make internal cuts within the lens) using both 2D and 3D finite element analysis. Some preliminary results are given in Geoffrey Wilde’s thesis. Our modelling work suggests that the accommodation performance of the lens can be improved by making internal cuts within the lens. However, the search for effective cutting patterns remains a challenge.