Femtosecond laser pulses can be delivered through transparent and translucent tissue to perform high precision surgical procedures without damage to superficial or adjacent tissues. These unique properties of femtosecond laser-tissue interactions may provide a marked advantage over traditional laser techniques for high precision subsurface procedures. We hypothesize that the application of femtosecond lasers to the treatment of glaucoma has several potential advantages over traditional surgical and laser treatments. Among these advantages, localized tissue effects, intra-scleral capabilities, highly precise beam delivery through the conjunctiva and sclera, minimally invasive treatments, short procedure times and a potentially decreased healing response are significant. To test our hypothesis we propose the evaluation of femtosecond laser created intra-scleral fistulas of various geometries for the facilitation of aqueous outflow. Initially, a comprehensive in vitro tissue study will be performed to understand the effects femtosecond laser cut fistulas on aqueous outflow and refine geometric requirements. Theoretical modeling of the aqueous outflow dynamics will also be performed in order to deeper understand the flow dynamics and to aid channel optimization. To ensure precise drainage channel creation, ultrasound imaging will be used to monitor the surgical procedures. Ultrasound imaging is a powerful tool that can provide high-resolution visualization of the femtosecond laser treatments in both optically transparent and non-transparent tissue. After the completion of the in vitro investigations animal experiments are planned to study the effect of femtosecond laser created intra-scleral fistulas on the aqueous humor outflow in vivo. Optimization of the experimental apparatus and surgical procedures will be first accomplished, allowing the execution of long-term wound-healing studies. The longevity and effectiveness of the femtosecond laser procedures will be compared to those of traditional surgical and laser therapies tested under similar conditions. The successful completion of this project will provide a proof of concept for a minimally invasive, high precision femtosecond laser treatment of glaucoma. Additionally, by providing information on the in vivo physiological properties of the aqueous humor outflow, the results will add to our understanding of the etiology and mechanisms of glaucoma.
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