Abstract: The invention relates to novel multifunctional organosiloxane monomers which can be represented by the general formulas: ##STR1## wherein, at least one of "X.sup.1 "-"X.sup.7 " is a group of the following structure: ##STR2## and its copolymerization with monofunctional organosiloxane monomers which can be represented by the general formulas: ##STR3## and alkyl and/or cyclic alkyl esters of acrylic, methacrylic acids and/or itaconate esters, and in some cases fluoroalkyl esters of acrylic, methacrylic acids and/or fluoroalkyl itaconate esters to produce excellent oxygen permeable hard contact lens material.Preferably, the copolymer includes cross-linking agents and wetting agents.Contact lenses manufactured from the materials can be easily machined and polished into hard contact lenses having solvent-resistance and sufficient permeabilities.

Abstract: A contact lens material made of an organosiloxane ester copolymer. The organosiloxane is represented by the general formula: ##STR1## and the ester is composed of C.sub.1 -C.sub.10 mono- or multi-valent alcohol and methacrylic acid, acrylic acid or itaconic acid. The contact lens is oxygen permeable and substantially free of water-absorption, so that it is easy to handle. It may be worn comfortably for extended period.