Lens with stain resistant surface layer

A lens comprising a lens substrate, a surface layer, and a backing member provided beneath the surface layer, wherein the backing member is either identical to the lens substrate, or a separate layer from the lens substrate, wherein the surface layer comprises a hydrolysis-condensation product of a perfluoropolyether modified silane represented by the formula (1) shown below:

• wherein, Rf is a bivalent group comprising a straight chain perfluoropolyether structure containing no branching and comprising a unit represented by a formula —(CkF2kO)— wherein, k represents an integer of 1-6, each R represents, independently, a monovalent hydrocarbon group of 1-8 carbon atoms, each X represents, independently, a hydrolysable group or a halogen atom, each n represents, independently, an integer of 0-2, each m represents, independently, an integer of 1-5, and each of a and b represents, independently, 2 or 3, and the surface layer is formed by vacuum-depositing the perfluoropolyether modified silane directly onto the backing member.

A process for producing a lens comprising vacuum-depositing a surface layer onto a lens substrate or a backing member on a lens substrate, wherein the surface layer comprises:

• a hydrolysis-condensation product of a perfluoropolyether modified silane represented by the formula (1) shown below:
• wherein, Rf is a bivalent group comprising a straight chain perfluoropolyether structure containing no branching and comprising a unit represented by a formula —(CkF2kO)— wherein, k represents an integer of 1-6, each R represents, independently, a monovalent hydrocarbon group of 1-8 carbon atoms, each X represents, independently, a hydrolysable group or a halogen atom, each n represents, independently, an integer of 0-2, each m represents, independently, an integer of 1-5 and each of a and b represents, independently, 2 or 3.