SHAPED ARTICLES WHICH ARE CONTACT LENSES OR BONNETS FOR CONTACT LENS FORMED FROM POLYMERS OF STYRENE TYPE MONOMERS

摘要

The invention provides shaped articles that are contact lenses or are bonnets from which such lenses may be made. The lenses have high gas permeability. They are formed of a polymer that is obtained by polymerising at least one styrenetype monomer, optionally with at least one cross-linking monomer and optionally with other mono-olefinically unsaturated monomer. Preferably the polymerisable monomers comprise, or consist of, a styrene substituted in the ring by at least one alkyl group.