An alternative to polycarbonates ophthalmic lenses: study of photo initiated polymerization of mono and multifunctional monomers for fast curing non proprietary ophthalmic lenses production.

Industrially organic ophthalmic lenses are manufactured mostly using thermal polymerization. The polymerization processes are initiated by heat and demand from 60 to 70 hours average for an isothermal process and from 18 to 20 hours for a no isothermal mainly to prevent defective lenses. Process improvements have been achieved reducing to 7 to 3 hours depending on initiator concentration 11 , as well as a process using modified monomers to reduce defective lenses ratio 15 . In this work, alternative materials have been studied for production of ophthalmic lenses using photo initiated polymerization. The average time of reaction necessary to polymerize the studied materials was 4 minutes, in according the thickness of the mold. The obtained lenses were characterized by hardness measurement, transmittance from 200 to 800 nm, refractive index and thermal analyses for determination of the glass transition temperature and heat resistance.