This Small Business Innovation Research (SBIR) Phase II project addresses the development of a UV curable bulk nanocomposite having enhanced optical and mechanical properties for ophthalmic lenses. The work focuses the incorporation of metal oxide nanoparticles into a transparent polymer to engineer the refractive index and mechanical properties. This requires the synthesis of stable nanoparticles approximately 20 nm or less in diameter. The nanoparticles require a surface treatment that will aid in the monomer stability and impart improved mechanical properties to the polymerized lens. The functionalized dispersion can then be incorporated into a second monomer and then polymerized into a finished ophthalmic eyeglass lens using the lens casting system currently used by several hundred Vision Dynamics LLC customers. This extends the capabilities of an independent retail dispenser to deliver quality eyeglass lenses to consumers in less than an hour. The project will further the understanding of nanocomposites which are a very unique and important material.
This SBIR Phase II project is directed toward the ophthalmic eyeglass lens market which is a $7B industry in the United States. Much of the eyeglass lenses in this industry are imported from overseas and through recent consolidations the three largest producers of lenses are foreign companies. If successful this technology removes the distribution rungs between the consumer and the optician, allowing independent retailers to more efficiently deliver quality eyewear to their customers. This allows retailers to continue to compete in this difficult landscape that has been dominated by acquisitions and mergers squeezing the independents. Furthermore, UV curing has been identified as a green coating technology for its low VOC emissions and low energy consumption. Currently UV cured polymers are limited in refractive index so this technology will play out in several industries.
This SBIR Phase II project focused on developing next generation technologies for its commercial ophthalmic lens products. These efforts aimed at increasing the refractive index beyond that of commercially obtainable radiation curable materials, as well as improving the impact and tear resistance of the current product. Specifically, the work focused on the inclusion of nanometer-sized metal oxides (zinc oxide and titanium dioxide) into the casting resins forming an optically transparent lens-forming nanocomposite. For the end user, this would translate to better optics with thinner, lighter and stronger lenses. Objectives included the synthesis and functionalization of metal oxide nanoparticles, and their formulation into high refractive index monomer. These formulations then followed in-mold casting and polymerization as ophthalmic lens nanocomposites. A solvothermal synthesis method was developed for preparing functionalized zinc oxide and titanium particles with good monodispersity and average particle sizes of 11-15 nm in diameter. Despite advances in understanding reaction conditions that lead to isolable functionalized metal oxides, haze remains a central challenge limiting the commercialization of nanoparticle included ophthalmic lens-forming nanocomposites. Additional efforts included surveying currently available raw materials to formulate a new lens product with improved tear resistance, and a refractive index that is matched to current VDL lens products. These efforts resulted in a lens formulation with approximately 25% increase in shear strength and tear. The team is currently commercialization this formulation as a new ophthalmic lens product. In addition, while haze limits the application of these particles in a bulk lens, they are suitable for optical coating applications. The team is currently commercialization improved anti-reflective coatings for current ophthalmic lens products.
