The objective of this research was to develop new strategies for the synthesis of novel optically clear highly oxygen permeable membranes exhibiting appropriate water uptake and mechanical properties for possible ophthalmic applications. Thus a series of bicontinuous amphiphilic conetworks containing well-defined poly(ethylene glycol) and polydimethylsiloxane segments crosslinked by three novel crosslinking/modifying agents were synthesized, characterized, and evaluated. This paper concerns the design and synthesis of the crosslinking/modifying agents (see Fig. 2), and their use for the synthesis of clear, highly oxygen permeable amphiphilic membranes. Select membranes exhibit outstanding oxygen permeabilities (> 200 barrers) far superior to contemporary commercial soft contact lenses, together with mechanical properties and water uptake appropriate for extended wear soft contact lens application. (c) 2006 Wiley Periodicals, Inc.