Development of an Epiretinal Electronic Visual Prosthesis

The Harvard Medical School—Massachusetts Institute of Technology Research Program
  • Joseph F. Rizzo
  • John Loewenstein
  • John Wyatt


Diseases of the retina and optic nerve are common causes of irreversible blind- ness. Given the lack of effective treatments, several laboratories are utilizing micro- electronic technology to develop either a cortical or retinal prosthesis. Each strategy offers certain advantages, but both face numerous and formidable challenges. Conse- quently, a clinically useful device of either type is still conceptual. The technological means to build prostheses are available but the ultimate obstacle is the integration of the technology with the brain. This review primarily focuses on our efforts to develop a retinal prosthesis. In particular we address the two problems that we believe to be most challenging: 1) need to demonstrate that retinal stimulation can produce “useful” vision in a blind patient, and 2) need to demonstrate long-term biocomopatibility of an implanted device in an animal.

Brindley produced crude visual sensations by stimulating the visual cortex in a blind patient 32 years ago.1 This early success coupled with the broad therapeutic poten- tial of a cortical prosthesis to treat blindness caused by damage of either the retina or optic nerve has made this pursuit attractive to many scientists. Developing a cortical prosthesis that remains functional and biocompatible for prolonged periods of time is a difficult task and progress has not surprisingly been slow.2 The convoluted surface of the mobile brain and the need for penetration of the subsurface layer of the visual cortex increase the difficulty of maintaining a stable interface. The potential risks of neurosurgery are also a formidable if not simply a psychological barrier for patients.


Ganglion Cell Retinitis Pigmentosa Cortical Response Retinal Surface Retinal Prosthesis 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Brindley G and Lewin W. The sensations produced by electrical stimulation of the visual cortex. J. Physiol (Lond). 1968;196:479–493.Google Scholar
  2. 2.
    Rizzo JF Wyatt J. Prospects for a visual prosthesis. Neuroscientist. 1997;3:251–262.CrossRefGoogle Scholar
  3. 3.
    Balkany T, Hodges A, and Luntz M. Update on cochlear implantation. Otolaryngol Clin North Am. 1996;29:277–289.PubMedGoogle Scholar
  4. 4.
    Stone J Barlow W. Morphometric analysis of macular photoreceptors and ganglion cells in retinas with retinitis pigmentosa. Arch Ophthalmol. 1992;110:1634–1639.PubMedGoogle Scholar
  5. 5.
    Humayun M, de Juan E, Dagnelie G, Greenberg RJ, Propst RH, and Phillips DH. Visual perception elicited by electrical stimulation of retina in blind humans. Arch Ophthalmol. 1996;114:40–46.PubMedGoogle Scholar
  6. 6.
    Chow A Chow V. Subretinal electrical stimulation of the rabbit retina. Neuroscience Letters. 1997;225:13–16.PubMedCrossRefGoogle Scholar
  7. 7.
    Zrenner E, Miliczek K, Gabal V, et al. The development of subretinal microphotodiodes for replacement of degenerated photoreceptors. Ophthalmic Res. 1997;29:269–280.PubMedCrossRefGoogle Scholar
  8. 8.
    Doty RW Grimm FR. Cortical responses to local electrical stimulation of retina. Experimental Neurology. 1962;5:319–334.PubMedCrossRefGoogle Scholar
  9. 9.
    Humayun M, Propst R, de Juan E, McCormick K, and Hickingbotham D. Bipolar surface electrical stimulation of the vertebrate retina. Arch Ophthalmol. 1994;112:110–116. $PubMedGoogle Scholar

Copyright information

© Kluwer Academic / Plenum Publishers 1999

Authors and Affiliations

  • Joseph F. Rizzo
    • 1
  • John Loewenstein
    • 1
  • John Wyatt
    • 1
  1. 1.Massachusetts Eye and Ear InfirmaryBoston

Personalised recommendations