Journal of Clinical and Experimental Ophthalmology
Open Access

Department of Biomedical Engineering, University of Southern California, Los Angeles, USA

Biography

Mark S. Humayun, MD, PhD, received his Bachelors of Science degree from Georgetown University in 1984, his Masters Doctorate from Duke University in 1989, and his PhD from the University of North Carolina, Chapel Hill in 1994. He completed his ophthalmology residency at Duke Eye Center and fellowships in both vitreoretinal and retinovascular surgery at Johns Hopkins Hospital. He stayed on as faculty at Johns Hopkins where he rose to the rank of associate professor before moving to USC in 2001.

Publications

• Research Article   
  Effects of Electrical Stimulation on Retinal Morphology as Seen with Optical Coherence Tomography
  Author(s): Alejandra Gonzalez-Calle*, V. Swetha E. Jeganathan, Mark S Humayun and James D Weiland
  
  Retinal prostheses provide blind patients with the ability to detect motion and locate large objects. Future implants will require smaller electrodes to improve resolution, but increased charge density may result, creating a safety concern. We developed a novel in vivo method to study the effects of electrical stimulation in the retina using real time Optical Coherence Tomography (OCT) imaging combined with micropositioning a stimulating electrode. We observed that electrical stimulation settings with both pulse rates at and greater than 100 Hz as well as charge density 1.22 mC/cm2 and above resulted in retinal thickening within minutes of stimulation, that affected several retinal layers. We showed with statistical significance that the median difference between the retinal thickness before and after stimulation was different from zero. In summar.. View More»
  DOI: 10.35248/2155-9570.20.11.858

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