Date on Master's Thesis/Doctoral Dissertation

5-2007

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Mechanical Engineering

Committee Chair

Keynton, Robert S.

Subject

Retina--Surgery; Retina--Diseases--Treatment

Abstract

Age-related macular degeneration (ARMD) and retinitis pigmentosa (RP) are the two leading causes of blindness in the world today. Despite enormous efforts and advances in clinical treatment of eye diseases, there is no established method or cure of degenerative processes in the eye, such as ARMD and RP. In these disorders, the primary cause of blindness is due to the loss of photoreceptors, however, the remaining conductive neural pathways in the inner retina are still intact and functional. As a result, the University of Louisville in collaboration with the Center of Innovative Visual Rehabilitation at the Eye and Ear Infirmary of Harvard University is currently developing a microelectrode array for direct stimulation of the epiretinal surface of the eye. A major problem associated with implantation of the microfabricated device is the inability to secure the implant to the epiretinal surface. To address this issue, our group designed retinal microtacks to attach the microelectrode arrays to the inner surface of the eye. Microtacks were successfully fabricated out of titanium and silicon using ultra-high-precision micromachining and microfabrication methods, respectively. Metrology was performed to verify the accuracy of both fabrication methods. Insertion and retention force experiments were performed on each tack design in fiber reinforced synthetic rubber and porcine eye tissue. Results show that the titanium microtack design required less insertion force and greater removal force than that of the other designs in the fiber reinforced synthetic rubber. The synthetic rubber experiments displayed repeatable results with minimal deviation. The porcine ocular tissue showed poor repeatability with high deviation across all microtack designs.

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