In JoVE (1)
Articles by Joel Villalobos in JoVE
Techniques for Processing Eyes Implanted With a Retinal Prosthesis for Localized Histopathological Analysis David A. X. Nayagam1,2,3, Ceara McGowan1, Joel Villalobos1, Richard A. Williams2,3, Cesar Salinas-LaRosa2,3, Penny McKelvie2,3, Irene Lo2,3, Meri Basa2,3, Justin Tan1, Chris E. Williams1,3,4 1Bionics Institute, 2Department of Anatomical Pathology, St Vincent's Hospital Melbourne, 3Department of Pathology, University of Melbourne, 4Medical Bionics Department, University of Melbourne Techniques for visualizing retinal cytoarchitecture directly adjacent to individual electrodes within a retinal stimulator.
Other articles by Joel Villalobos on PubMed
Development of a Surgical Approach for a Wide-view Suprachoroidal Retinal Prosthesis: Evaluation of Implantation Trauma Graefe's Archive for Clinical and Experimental Ophthalmology = Albrecht Von Graefes Archiv FÃ¼r Klinische Und Experimentelle Ophthalmologie. Mar, 2012 | Pubmed ID: 21874343 Our research goal is to develop a safe, reproducible surgical approach for implantation of a wide-field retinal stimulating array. The aim of this study was to evaluate the pathological response to acute implantation of a functional prototype electrode array in the suprachoroidal space.
A Wide-field Suprachoroidal Retinal Prosthesis is Stable and Well Tolerated Following Chronic Implantation Investigative Ophthalmology & Visual Science. Apr, 2013 | Pubmed ID: 23611996 PURPOSE: The safety of chronic implantation of a retinal prosthesis in the suprachoroidal space has not been established. This study aimed to determine the safety of a wide-field suprachoroidal electrode array following chronic implantation using histopathological techniques and electroretinography. METHODS: A platinum electrode array in a wide silicone substrate was implanted unilaterally in the suprachoroidal space in cats (n = 7). The lead and connector were tunneled out of the orbit and positioned subcutaneously. Post-surgical recovery was assessed using fundus photography and electroretinography (ERG). Following 3 months of passive implantation, the animals were terminated and the eyes assessed for the pathological response to implantation. RESULTS: The implant was mechanically stable in the suprachoroidal space during the course of the study. The implanted eye showed a transient increase in ERG response amplitude at 2 weeks which returned to normal by 3 months. Pigmentary changes were observed at the distal end of the implant, near the optic disc. Histopathological assessment revealed a largely intact retina and a thin fibrous capsule around the suprachoroidal implant cavity. The foreign body response was minimal with sporadic presence of macrophages and no active inflammation. All implanted eyes were negative for bacterial or fungal infections. A mid-grade granuloma and thick fibrous build-up surrounded the extraocular cable. Scleral closure was maintained in 6 of 7 eyes. There were no staphylomas or choroidal incarceration. CONCLUSIONS: A wide-field retinal prosthesis was stable and well tolerated during long-term suprachoroidal implantation in a cat model. The surgical approach was reproducible and overall safe.