The invention provide a class of linear chain-extended polysiloxane crosslinkers which comprises two terminal ethylenically unsaturated groups, at least two polysiloxane segments, and dangling hydrophilic polymer chains each covalently attached to a divalent organic radical separating each pair of adjacent polysiloxane segments. The present invention is also related to a polymer comprising crosslinking units derived from chain-extended polysiloxane crosslinker of the invention and to ophthalmic lenses comprising such a polymer.
