This SBIR Phase I project aims to improve the surgical treatment used for patients suffering from open angle glaucoma (OAG), through the development and testing of the world's thinnest ocular implant. OAG is the most common form of glaucoma, the leading cause of irreversible blindness in the world. By 2020, glaucoma will affect 3.4 million people in the U.S. and 80 million people globally. In the U.S., glaucoma incurs over $4 billion in medical and societal costs per year. For patients with glaucoma, elevated eye pressure must be lowered to protect the optic nerve from damage. However, conventional surgical implant treatments are bulky, highly invasive, and cause chronic discomfort. While newer, smaller devices are less invasive, they present issues with long-term efficacy as they inadequately sustain lower eye pressure when scarring occurs. This project will develop an implant many times thinner than a human hair to safely reduce eye pressure while minimizing the risk of patient discomfort and failure from scarring. The nanotechnology-enabled device will be designed to facilitate biocompatibility, patient comfort, and physician insertion through a combination of mechanical and materials engineering. Beyond the application in glaucoma, the technology developed will play a key role in future permanent and efficacious ocular implants - a rapidly growing component of vision care. This innovation involves careful engineering of the materials composition and microarchitecture of an ultrathin implant to treat glaucoma. Specifically, the project will optimize a novel corrugated microstructure for a unique combination of mechanical and fluid flow properties. Specific corrugations will provide the stiffness required for handling by physicians, as well as the flexibility to conform to soft eye tissues. Microchannels from the corrugations will also be patterned to provide adequate flow for reducing intraocular pressure, while providing enough resistance to prevent overly low pressure. Microscale architecture and materials will first be engineered through experimental testing of tensile stiffness, bending stiffness, shear strength, aqueous stability, and pressure flow characteristics. The implant with the optimal materials microarchitecture will subsequently be studied in an in vivo leporine eye model. This study will monitor intraocular pressure, scar tissue formation, levels of inflammation, adverse events, and implant stability. Together, the bench and pre-clinical tests will provide critical data for further refinement of this implant and facilitate progress towards realizing an optimal defense against blindness. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
