Resolution of the Epiretinal Prosthesis is not Limited by Electrode Size

Epiretinal prostheses for the blind bypass diseased photosensitive cells in the retina, directly stimulating retinal neurons electrically and evoking signals that are relayed to the brain. Current clinical implants have few electrodes and provide limited visual acuity. Acuity may be improved by identifying electrode array design features and operational details that enhance or interfere with visual percept formation. We labeled all retinal ganglion cells in whole mount retina with a calcium reporter and then measured the number and pattern of cells responding, over a range of electrode diameters and stimulus durations. Span of the response scaled with electrode diameter for electrodes 60 μm and larger. Short stimulation pulse widths selectively activated cells nearest the electrode. Our measurements in the salamander retina suggest that the spatial resolution is 150 μm, which on a human retina is equivalent to 0.55° of human visual field and corresponding Snellen acuity of 20/660. Reading large print could be possible with such a prosthesis.

[1]  Yuzuru Takamura,et al.  Investigating neuronal activity with planar microelectrode arrays: achievements and new perspectives. , 2005, Journal of bioscience and bioengineering.

[2]  D.B. McCreery,et al.  Charge density and charge per phase as cofactors in neural injury induced by electrical stimulation , 1990, IEEE Transactions on Biomedical Engineering.

[3]  Avi Caspi,et al.  Feasibility study of a retinal prosthesis: spatial vision with a 16-electrode implant. , 2009, Archives of ophthalmology.

[4]  J. Rubinstein,et al.  In vitro measurement and characterization of current density profiles produced by nonrecessed, simple recessed, and radially varying recessed stimulating electrodes , 1991, IEEE Transactions on Biomedical Engineering.

[5]  Joseph F Rizzo,et al.  Selective activation of neuronal targets with sinusoidal electric stimulation. , 2010, Journal of neurophysiology.

[6]  G. Gross,et al.  Transparent indium-tin oxide electrode patterns for extracellular, multisite recording in neuronal cultures , 1985, Journal of Neuroscience Methods.

[7]  J. Holladay,et al.  Visual acuity measurements. , 2004, Journal of cataract and refractive surgery.

[8]  R. Sharma,et al.  Management of hereditary retinal degenerations: present status and future directions. , 1999, Survey of ophthalmology.

[9]  Daniel R. Merrill,et al.  Electrical stimulation of excitable tissue: design of efficacious and safe protocols , 2005, Journal of Neuroscience Methods.

[10]  J. Weiland,et al.  Selective labeling of retinal ganglion cells with calcium indicators by retrograde loading in vitro , 2009, Journal of Neuroscience Methods.

[11]  P. L. Carras,et al.  Site of action potential initiation in amphibian retinal ganglion cells. , 1992, Journal of neurophysiology.

[12]  Tim Gollisch,et al.  Rapid Neural Coding in the Retina with Relative Spike Latencies , 2008, Science.

[13]  A.M. Litke,et al.  What does the eye tell the brain?: Development of a system for the large scale recording of retinal output activity , 2003, 2003 IEEE Nuclear Science Symposium. Conference Record (IEEE Cat. No.03CH37515).

[14]  Joseph F Rizzo,et al.  Thresholds for activation of rabbit retinal ganglion cells with an ultrafine, extracellular microelectrode. , 2003, Investigative ophthalmology & visual science.

[15]  C. Karwoski,et al.  Laminar profile of resistivity in frog retina. , 1985, Journal of neurophysiology.

[16]  R. Masland.  Neuronal diversity in the retina , 2001, Current Opinion in Neurobiology.

[17]  S. Fried,et al.  Axonal sodium-channel bands shape the response to electric stimulation in retinal ganglion cells. , 2009, Journal of neurophysiology.

[18]  E. Chichilnisky,et al.  Electrical stimulation of mammalian retinal ganglion cells with multielectrode arrays. , 2006, Journal of neurophysiology.

[19]  G D Field,et al.  Information processing in the primate retina: circuitry and coding. , 2007, Annual review of neuroscience.

[20]  R. Jensen,et al.  Thresholds for activation of rabbit retinal ganglion cells with relatively large, extracellular microelectrodes. , 2005, Investigative ophthalmology & visual science.

[21]  S. Kelly,et al.  Perceptual efficacy of electrical stimulation of human retina with a microelectrode array during short-term surgical trials. , 2003, Investigative ophthalmology & visual science.

[22]  Eyal Margalit,et al.  Inner retinal mechanisms engaged by retinal electrical stimulation. , 2006, Investigative ophthalmology & visual science.

[23]  D. Dacey.  Primate retina: cell types, circuits and color opponency , 1999, Progress in Retinal and Eye Research.

[24]  A. Milam,et al.  Preservation of the inner retina in retinitis pigmentosa. A morphometric analysis. , 1997, Archives of ophthalmology.

[25]  E. Chichilnisky,et al.  High-Resolution Electrical Stimulation of Primate Retina for Epiretinal Implant Design , 2008, The Journal of Neuroscience.

[26]  N Drasdo,et al.  Non-linear projection of the retinal image in a wide-angle schematic eye. , 1974, The British journal of ophthalmology.

[27]  Arup Roy,et al.  Factors affecting perceptual thresholds in epiretinal prostheses. , 2008, Investigative ophthalmology & visual science.

[28]  James D. Weiland,et al.  Dynamic Current Density of the Disk Electrode Double-Layer , 2008, IEEE Transactions on Biomedical Engineering.

[29]  J. Weiland,et al.  Retinal prosthesis for the blind. , 2002, Survey of ophthalmology.

[30]  S. Massey,et al.  Glutamate receptors of ganglion cells in the rabbit retina: evidence for glutamate as a bipolar cell transmitter. , 1988, The Journal of physiology.

[31]  Gislin Dagnelie,et al.  Visually guided performance of simple tasks using simulated prosthetic vision. , 2003, Artificial organs.

[32]  Michael J. Berry,et al.  Recording spikes from a large fraction of the ganglion cells in a retinal patch , 2004, Nature Neuroscience.

[33]  F. Werblin,et al.  A method for generating precise temporal patterns of retinal spiking using prosthetic stimulation. , 2006, Journal of neurophysiology.

[34]  Thomas Schanze,et al.  Visual resolution with retinal implants estimated from recordings in cat visual cortex , 2006, Vision Research.

[35]  J. Kaas,et al.  Reorganization of retinotopic cortical maps in adult mammals after lesions of the retina. , 1990, Science.

[36]  M. Mcmahon,et al.  Retinal prosthesis phosphene shape analysis , 2008, 2008 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[37]  J. Newman.  Resistance for Flow of Current to a Disk , 1966 .

[38]  A. M. Potts,et al.  The electrically evoked response (EER) of the visual system. II. Effect of adaptation and retinitis pigmentosa. , 1969, Investigative ophthalmology.

[39]  T.L. Rose,et al.  Electrical stimulation with Pt electrodes. VIII. Electrochemically safe charge injection limits with 0.2 ms pulses (neuronal application) , 1990, IEEE Transactions on Biomedical Engineering.

[40]  J. Rizzo,et al.  Multi-electrode stimulation and recording in the isolated retina , 2000, Journal of Neuroscience Methods.