The University of Florida is seeking companies interested in commercializing inexpensive UV-blocking contact lenses that are easier to make than existing lenses and a device for manufacturing them. Long known to induce premature aging and promote skin cancer, sun exposure also damages delicate structures of the eye. For example, it can cause photokeratitis or “snowblindness” - a temporary (but painful) “sunburn” to the cornea. Because damage is cumulative, even low-level exposure can lead to serious health problems, such as permanent retinal damage and cataracts (clouding of the eye’s natural lens that occludes vision). The World Health Organization estimates that 900,000 people across the globe are legally blind as a direct result of UV-induced cataracts. Wrap-around sunglasses combined with a wide-brimmed hat or UV-blocking contact lenses offer the best protection for eyes. Unfortunately, only a few types of expensive commercial contact lenses are approved as Class 1 UV blockers. Recognizing that the market demands a lower-cost alternative, researchers at the University of Florida have developed unique nanoparticle-tinted contact lenses that are easier to manufacture. UV-blocking materials are encapsulated in nanoparticles, which are then incorporated into pre-fabricated contact lenses by soaking the lenses in a solution of nanoparticles in ethanol. The resulting product is inexpensive and achieves a high level of protection against sun damage superior to current Class 1 UV blocking contact lenses. The lenses retain Class 1 UV blocking after packaging and autoclaving. The global market for contact lenses is expected to reach $11.7 billion by 2015. Nanoparticle-tinted lenses could capture a significant portion of this business.
Low-cost contact lenses that protect the eye against sun damage and a device for easily dispersing the UV-blocking compounds into the lenses
- Reduces the amount of radiation that reaches the cornea and retina, decreasing the incidence of UV-induced eye problems
- Incorporates particles through the polymerization mixture, reducing the required light intensity and curing time in manufacturing
- Compatible with any UV blocking agent, enhancing versatility and lowering production costs
- Can convert prefabricated contact lenses into Class 1 UV blockers, and can be adapted to any commercial contact lens
The UV blocking feature is typically incorporated into contact lenses by adding a UV-absorbing molecule to the lens composition. Major challenges in preparing a contact lens loaded with UV blocker include lengthy curing time, the need for intense lights and/or compromises in product quality. University of Florida researchers have developed unique UV-blocking contact lenses that mitigate these problems. The researchers encapsulated UV blocking materials in nanoparticles and then adsorb the nanoparticles into prefabricated silicone hydrogel contact lenses by soaking the lenses in a solution of particles in ethanol. The ethanol-swelled lenses allow nanoparticles to be absorbed into the lenses, and then deswelling the lenses by soaking in PBS traps the particles in the lenses. Nanoparticle crosslinking prevents the UV blocking materials from leaching out of the lenses, eliminating the need for copolymerization and permitting the use of any UV blocking agent. This approach has been proven to be compatible with most commercial contact lenses and can easily be adapted to any contact lens or other device that needs to be designed to be UV blocking.