High modulus hydrogels for ophthalmic and related biomedical applications.

This paper presents three families of semi-interpenetrating polymer network (SIPN) hydrogels based on an ester-based polyurethane (EBPU) and hydrophilic monomers: N,N-dimethylacrylamide (NNDMA), N-vinyl pyrrolidone (NVP) and acryloylmorpholine (AMO) as potential materials for keratoprosthesis, orthokeratology and mini-scleral lens application. Hydrogels sheets were synthesized via free-radical polymerization with methods developed in-house. SIPN hydrogels were characterized for their equilibrium water content, mechanical and surface properties.

Mechanical properties of contact lenses: The contribution of measurement techniques and clinical feedback to 50 years of materials development.

Purpose: This review summarises the way in which mechanical property measurements combined with clinical perception have influenced the last half century of materials evolution in contact lens development.

Methods: Literature concerning the use of in-vitro testing in assessment of the mechanical behaviour of contact lenses, and the mutual deformation of the lens material and ocular tissue was examined. Tensile measurements of historic and available hydrogel lenses have been collected, in addition to manufacturer-generated figures for the moduli of commercial silicone hydrogel lenses.