Mark Humayun is a retinal surgeon and biomedical engineer at the Doheny Eye Institute at the University of Southern California, He has combined his multiple areas of expertise into the development of the artificial retina for the treatment of photoreceptor loss.
The premise of the artificial retina project is to take images from a glass-worn camera and convert it into patterns of electrical stimulations that would excite the remaining retinal neurons and when transmitted to the brain via the optic nerve result in restoring useful visual cues. In so doing, the artificial retina would by pass the loss of the photoreceptor function. The critical questions in the development of the artificial retina lie in how best to electrically and mechanically interface the implanted electronics with the remaining retinal neurons (e.g., retinal ganglion cells). A specific critical challenge is to deliver enough power to the implanted device so it can stimulate the remaining retinal neurons in multiple areas and also in a manner that is the most efficient means of delivering the power without wires across the eye and minimizing heat dissipation that could irreversibly damage the retinal neurons.
At Doheny Eye Institute at the University of Southern California, Humayun and his collaborators have implanted the first of its kind microelectronic retinal implant into the eyes of 6 blind patients with end-stage retinitis pigmentosa. These results have allowed us to study various electrical and mechanical parameters over long-term (1-2.5 years) in these blind patients. These parameters will provide the target specifications to which our first biobattery will be designed. Humayun will interact with the Center continually as we develop the technical capability to design and fabricate the first biobattery.
Dagnelie G. Barnett D. Humayun MS. Thompson RW Jr. Paragraph text reading using a pixelized prosthetic vision simulator: parameter dependence and task learning in free-viewing conditions. Investigative Ophthalmology & Visual Science. 47(3):1241-50.
Weiland JD. Humayun MS. A biomimetic retinal stimulating array. IEEE Engineering in Medicine & Biology Magazine. 24(5):14-21, 2005.
Weiland JD. Humayun MS. Old idea, new technology. IEEE Engineering in Medicine & Biology Magazine. 24(5):12-3, 2005.
Khurana RN. Fujii GY. Walsh AC. Humayun MS. de Juan E Jr. Sadda SR. Rapid recurrence of geographic atrophy after full macular translocation for nonexudative age-related macular degeneration. Ophthalmology. 112(9):1586-91, 2005.
Weiland JD. Liu W. Humayun MS. Retinal prosthesis. Annual Review of Biomedical Engineering. 7:361-401, 2005.
Mahadevappa M. Weiland JD. Yanai D. Fine I. Greenberg RJ. Humayun MS. Perceptual thresholds and electrode impedance in three retinal prosthesis subjects. IEEE Transactions on Neural Systems & Rehabilitation Engineering. 13(2):201-6, 2005.