Biomedical Engineering Seminar: Restoring Dynamic Vision - Curable Polysiloxane Gels
Room 202 (Masters Seminar Room 2)
Old Metallurgy Building
T: (03) 8344 6606
Presbyopia is a condition in which the aging eye loses its ability to focus on close objects (accommodation), due to hardening of the natural lens. While wearing reading glasses remains the most common solution to this condition they cannot provide dynamic accommodation due to their fixed focal length. An attractive potential solution to presbyopia involves replacing the hardened natural lens with a gel soft enough to allow accommodation.
In this study, functional polysiloxanes macromonomers have been investigated as possible candidate materials to replace the hardened natural lens for correction of presbyopia. This requires a biostable and biocompatible polysiloxane to be injected into the capsular bag in a liquid form and cured in situ to form a soft gel. These polymers are designed to mimic the optical and mechanical properties of a young person’s natural lens by having a low storage modulus (G´) (<5 kPa), a suitable viscosity (<25 Pa.s), and a refractive index (1.43) that is comparable to the natural human lens. Soft gels with desired properties can be achieved by altering the refractive index, viscosity (injectability), and post-cure modulus, via adjusting aromatic ratio along the backbone, the molecular weight, and crosslink density, respectively, with the aid of a factorial design optimisation. In addition, their suitability for this application is further illustrated by their promising results in ex-vivo lens stretching and animal studies.
The resulting polymers are able to closely mimic both the optical and mechanical properties of a young natural lens and hence should enable the restoration of the eye’s ability to focus dynamically.