DESCRIPTION: Gas permeable bifocal contact lenses are potentially useful for large number of presbyopic subjects. Though many bifocal and multifocal lens designs are available, none have been implemented with sufficient oxygen permeability and excellent near and distant vision to meet the population range of refractive corrections requirements. The fused, rigid gas-permeable bifocal contact lenses currently available suffers from aberrant flaws in the center of the lens where most vision occurs. The applicants will develop new bifocal and multifocal contact lenses by fusing optical wedges made of novel polymer-glass composites to available rigid gas-permeable contact lenses. The polymer-glass composite materials, have adjustable rigidity, refractive index and specific gravity and can be cast or machined. Composite materials with high index of refraction and high specific gravity will be used for producing thin correction lenses that will then be bonded to the silicone acrylate gas-permeable contact lens materials. The resulting bifocal or multifocal lenses will not need the prism ballast used in the currently available fuses bifocal lenses, instead the high density composite portion of the new lenses will be the ballast to orient the lens.National Eye Institute (NEI)
