Microelectronic Visual Prostheses

Part of the Biological and Medical Physics, Biomedical Engineering book series (BIOMEDICAL)


Research efforts worldwide are developing microelectronic visual prostheses aimed at restoring vision for the blind. Various visual prostheses using neural stimulation techniques targeting different locations along the visual pathway are being pursued. Retinal prostheses have proved to be capable of offering blind subjects in advanced stages of outer retinal diseases the opportunity to regain some visual function. With relatively low-density retinal implants, simple visual tasks that are impossible with the blind subject’s natural light perception vision can be accomplished. Blind subjects can spatially resolve individual electrodes within the array of the implanted retinal prosthesis and can use the system to discriminate and identify oriented patterns. This chapter reviews progress in the development of visual prostheses including visual cortex and optic nerve stimulation devices and retina stimulation devices such as epiretinal, subretinal, and extraocular implants. Second Sight Argus 16 and Argus II 60-electrode Retinal Implants are described. Some engineering challenges for the development of visual prostheses, especially retinal prostheses, are discussed.


Retinitis Pigmentosa Electrode Array Lateral Geniculate Nucleus Microelectrode Array Blind Subject 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This work was supported by the National Institute of Health – National Eye Institute (NEI), under NIH Grant EY012893 and by the Artificial Retina Project of Department of Energy (DOE Lab 01-14 Project). Authors are grateful to Chase Byers for his help in preparing the manuscript.


  1. 1.
    Census (1997) Americans with Disabilities: US Census BureauGoogle Scholar
  2. 2.
    Heckenlively JR, Boughman J, Friedman L (1988) Diagnosis and classification of retinitis pigmentosa. In: Heckenlively JR (Ed) Retinitis pigmentosa, JB Lippincott Philadelphia, PhiladelphiaGoogle Scholar
  3. 3.
    Klein R, Klein BE, Jensen SC, et al. (1997) The five-year incidence and progression of age-related maculopathy: the beaver dam eye study. Ophthalmology 104:7–21Google Scholar
  4. 4.
    Klein R, Klein BE, Tomany SC, et al. (2002) Ten-year incidence and progression of age-related maculopathy: The Beaver Dam eye study. Ophthalmology 109:1767–1779Google Scholar
  5. 5.
    Greenberg R (2000) Visual prostheses: A review. Neuromodulation 3:161–165Google Scholar
  6. 6.
    Humayun MS, Freda R, Fine I, et al. (2005) Implanted intraocular retinal prosthesis in six blind subjects. IOVS 46:1144Google Scholar
  7. 7.
    Zrenner Z (2002) Will retinal implants restore vision? Science 295:1022–1025Google Scholar
  8. 8.
    Chow A, Chow V, Packo K, et al. (2004) The artificial silicon retina microchip for the treatment of vision loss from retinitis pigmentosa. Arch Ophthalmol 122:460–469Google Scholar
  9. 9.
    Rizzo J, Wyatt J, Humayun M, et al. (2001) Retinal prosthesis: an encouraging first decade with major challenges ahead. Ophthalmology 108:13–14Google Scholar
  10. 10.
    Normann RA, Maynard EM, Rousche PJ, et al. (1999) A neural interface for a cortical vision prosthesis. Vision Res 39:2577–2587Google Scholar
  11. 11.
    Hahn FJ, Chu WK (1984) Ocular volume measured by CT scans. Neuroradiology 26:419–420Google Scholar
  12. 12.
    Foulds WS (1976) Clinical significance of trans-scleral fluid transfer. Trans Ophthalmol Soc UK 96:290–308Google Scholar
  13. 13.
    Berman E (1991) Retina. In: Berman ER (ed) Biochemistry of the eye. Plenum Press, NY, pp 309–315Google Scholar
  14. 14.
    Manzanas LL, Pastor JC, Munoz R, et al. (1992) Intraocular irrigating solutions and vitrectomy-related changes (in protein, lactic and ascorbic acid) in rabbit vitreous. Ophthalmic Res 24:61–67Google Scholar
  15. 15.
    Kolb H, Fernandez E, Nelson R (2008) Webvision, the Organization of the Retina and Visual system, http://webvision.med.utah.edu, Accessed 10 December, 2008
  16. 16.
    Geddes LA, Baker LE (1967) The specific resistance of biological material-A compendium of data for the biomedical engineer and physiologist. Med Biol Eng 5:271–291Google Scholar
  17. 17.
    Greenberg R (1998) Analysis of electrical stimulation of the vertebrate retina: Work towards a retinal prosthesis. Johns Hopkins University, Baltimore, MDGoogle Scholar
  18. 18.
    Allen M (1990) Adjusting to visual impairment. J Ophthalmic Nurs Technol 9:47–51Google Scholar
  19. 19.
    Leinhaas MA, Hedstrom NJ (1994). Low vision: how to assess and treat its emotional impact. Geriatrics 49:53–56Google Scholar
  20. 20.
    Humayun MS, Weiland JD, Fujii GY, et al. (2003) Visual perception in a blind subject with a chronic microelectronic retinal prosthesis. Vision Res 43:2573–2581Google Scholar
  21. 21.
    Clausen J (1955) Visual sensations (Phosphenes) produced by AC sine wave stimulation. Acta Physiol Neurol Scand Supp 94:1–101Google Scholar
  22. 22.
    Brindley G, Lewin W (1968) The sensations produced by electrical stimulation of the visual cortex. J Physiol (London) 196:479–493Google Scholar
  23. 23.
    Weiland JD, Humayun MS (2008) Visual prosthesis. Proc IEEE 96:1076–1084Google Scholar
  24. 24.
    Niu J, Liu Y, Ren Q, et al. (2008) Vision implants: An electrical device will bring light to the blind. Sci China Ser F-Inf Sci 51:101–110Google Scholar
  25. 25.
    Pezaris JS, Reid RC (2007) Demonstration of artificial visual percepts generated through thalamic microstimulation. PNAS 104:7670–7675Google Scholar
  26. 26.
    Humayun M, de Juan E, Dagnelie G, et al. (1996) Visual perception elicited by electrical stimulation of the retina in blind humans. Arch Ophthalmol 114:40–46Google Scholar
  27. 27.
    Humayun M, de Juan E, Weiland J, et al. (1999) Pattern electrical stimulation of the human retina. Vision Res 39:2569–2576Google Scholar
  28. 28.
    Eckmiller R (1997) Learning retina implants with epiretinal contacts. Ophthalmic Res 29:281–289Google Scholar
  29. 29.
    Rizzo J, Wyatt J (1997) Prospects for a visual prosthesis. Neuroscientist 3:251–262.Google Scholar
  30. 30.
    Chow AY, Chow VY (1997) Subretinal electrical stimulation of the rabbit retina. Neurosci Lett 225:13–16Google Scholar
  31. 31.
    Zrenner, E, Miliczek KD, Gabel VP, et al. (1997) The development of subretinal microphotodiodes for replacement of degenerated photoreceptors. Ophthalmic Res 29:269–280Google Scholar
  32. 32.
    Wyatt J, Rizzo J (1996) Ocular implants for the blind. IEEE Spectrum 33:47–53Google Scholar
  33. 33.
    Rizzo JF, John Wyatt J, Loewenstein J, et al. (2003) Perceptual efficacy of electrical stimulation of human retina with a microelectrode array during short-term surgical trials. IOVS 44:5362–5369Google Scholar
  34. 34.
    Robblee LS, Rose TL (1990) Electrochemical guidelines for selection of protocols and electrode materials for neural stimulation, In: Agnew WF, McCreery DB (eds) Neural Prostheses fundamental studies, Prentice Hall, Englewood Cliffs, NJ, pp 26–66Google Scholar
  35. 35.
    Richard G, Hornig R, Keseru M, et al. (2007) Chronic epiretinal chip implant in blind patients with retinitis pigmentosa: Long-term clinical results. Presented at the ARVO Annu. Meeting, Ft. Lauderdale, FLGoogle Scholar
  36. 36.
    Hornig R, Zehnder T, Velokay-Parel M, et al. (2007) The IMI Retinal Implant System. In: Humayun MS, et al. (eds) Artificial Sight, Basic Research, Biomedical Engineering, and Clinical Advances, Chapter 6, Springer, New York, pp 111–128Google Scholar
  37. 37.
    Wickelgren I (2006) A Vision for the blind. Science 312:1124–1126Google Scholar
  38. 38.
    Meyer JW (2001) Retina Implant – A BioMEMS Challenge. The 11th International Conference on Solid-State Sensors and Actuators, June 10–14, 2001, Munich, GermanyGoogle Scholar
  39. 39.
    Sailer H, Shinoda K, Blatsios G, et al. (2007) Investigation of thermal effects of infrared lasers on the rabbit retina: a study in the course of development of an active subretinal prosthesis. Graefe’s Arch Clin Exp Ophthalmol 245:1169–1178Google Scholar
  40. 40.
    Zrenner E, Besch D, Bartz-Schmidt KU, et al. (2006) Subretinal chronic multi-electrode arrays in blind patients: Function testing and pattern recognition. Proceeding of 5th International meeting on substrate-integrated micro electrode arrays, July 4–7, 2006, Germany, p 90Google Scholar
  41. 41.
    Winter JO, Cogan SF, Rizzo JF (2007) Retinal prostheses: current challenges and future outlook. J Biomater Sci Polymer Ed 18:1031–1055Google Scholar
  42. 42.
    Graf H, Dollberg A, Spuntrup JS (2007) HDR Sub-retinal Implant for the Vision Impaired. In: High-Dynamic-Range (HDR) Vision. Springer Berlin Heidelberg, pp 141–146Google Scholar
  43. 43.
    Besch D, Sachs H, Szurman P, et al. (2008) Extraocular surgery for implantation of an active subretinal visual prosthesis with external connections: feasibility and outcome in seven patients. Br J Ophthalmol 92:1361–1368Google Scholar
  44. 44.
    Zrenner E (2007) Restoring neuroretinal function: New potentials. Doc Ophthalmol 115:56–59Google Scholar
  45. 45.
    Palanker D, Vankov A, Huie P, et al. (2005) Design of a high-resolution optoelectronic retinal prosthesis. J Neural Eng 2:105–120Google Scholar
  46. 46.
    Butterwick A, Huie P, Jones BW, et al. (2008) Effect of shape and coating of a subretinal prosthesis on its integration with the retina. Experimental Eye Research, doi:10.1016/j.exer.2008.09.018. Available online 10 October 2008Google Scholar
  47. 47.
    Loudin JD, Simanovskii DM, Vijayraghavan K (2007) Optoelectronic retinal prosthesis: System design and performance. J Neural Eng 4:S72–S84Google Scholar
  48. 48.
    Marc RE, Jones BW, Watt CB, et al. (2003) Neural remodeling in retinal degeneration. Prog Retin Eye Res 22:607–655Google Scholar
  49. 49.
    Chowdhury V, Morley JW, Coroneo MT (2005) Feasibility of extraocular stimulation for a retinal prosthesis. Can J Ophthalmol 40:563–572Google Scholar
  50. 50.
    Sakaguchi H, Fujikado T, Fang X, et al. (2004) Transretinal electrical stimulation with a suprachoroidal multichannel electrode in rabbit eyes. Jpn J Ophthalmol 48:256–261Google Scholar
  51. 51.
    Seo J, Zhou J, Kim E, et al. (2007) A Retinal Implant System Based on Flexible Polymer Microelectrode Array for Electrical Stimulation. In: Tombran-Tink J, Barnstable CJ and Rizzo JF (eds) Visual prosthesis and ophthalmic devices new hope in sight. Humana Press, New JerseyGoogle Scholar
  52. 52.
    Zhou JA, Woo SJ, Park SI, et al. (2008) A Suprachoroidal Electrical Retinal Stimulator Design for Long-Term Animal Experiments and In Vivo Assessment of Its Feasibility and Biocompatibility in Rabbits. J Biomedicine and Biotech doi:10.1155/2008/547428,10 pages.Google Scholar
  53. 53.
    An SK, Park SI, Jun SB, et al. (2007) Design for a simplified cochlear implant system. IEEE Trans Biomed Eng 54:973–982Google Scholar
  54. 54.
    Yamauchi Y, Franco LM, Jackson DJ, et al. (2005) Comparison of electrically evoked cortical potential thresholds generated with subretinal or suprachoroidal placement of a microelectrode array in the rabbit. J Neural Eng 2:S48–S56Google Scholar
  55. 55.
    Gerding H (2007) A new approach towards a minimal invasive retina implant. J Neural Eng 4:S30–S37Google Scholar
  56. 56.
    Brindley G, Donaldson P, Falconer M, et al. (1972) The extent of the region of occipital cortex that when stimulated gives phosphenes fixed in the visual field. J Physiol (London) 225:57–58Google Scholar
  57. 57.
    Dobelle WH, Mladejovsky MG, Girvin JP (1974). Artificial vision for the blind: electrical stimulation of visual cortex offers hope for a functional prosthesis. Science 183:440–444Google Scholar
  58. 58.
    Dobelle WH, Mladejovsky MG, Evans JR, et al. (1976) Braille’ reading by a blind volunteer by visual cortex stimulation. Nature 259:111–112Google Scholar
  59. 59.
    Pollen DA (1975) Some perceptual effects of electrical stimulation of the visual cortex in man. In: Tower DB (ed) The nervous system, Vol 2: the clinical neurosciences. Raven Press, New YorkGoogle Scholar
  60. 60.
    Brindley G (1972) The variability of the human striate cortex. J Physiol (London) 225:1–3Google Scholar
  61. 61.
    Rousche P, Normann R (1998) Chronic recording capability of the Utah Intracortical Electrode array in cat sensory cortex. J Neurosci Methods 82:1–15Google Scholar
  62. 62.
    Hoverer A, Wise K (1994) A three-dimensional micro-electrode array for chronic neural recording. IEEE Trans Biomed Eng 41:1136–1146Google Scholar
  63. 63.
    Bak M, Girvin J, Hambrecht F, et al. (1990) Visual sensations produced by intracortical microstimulation of human occipital cortex. Med Biol Eng Comp 28:257–259Google Scholar
  64. 64.
    Schmidt EM, Bak MJ, Hambrecht FT, et al. (1996) Feasibility of a visual prosthesis for the blind based on intracortical micro stimulation of the visual cortex. Brain 119:507–522Google Scholar
  65. 65.
    Troyk P, Bak M, Berg J, et al. (2003) A model for intracortical visual prosthesis research. Artif Organs 27:1005–1015Google Scholar
  66. 66.
    Veraart C, Raftopoulos C, Mortimer J (1998) Visual sensations produced by optic nerve stimulation using an implanted self-sizing spiral cuff electrode. Brain Res 813:181–186Google Scholar
  67. 67.
    Veraart C, Delbeke J, Wanet-Defalque MC, et al. (1999) Chronic electrical stimulation of the optic nerve in a retinitis pigmentosa blind volunteer. Invest Ophthalmol Vis Sci 40:S783Google Scholar
  68. 68.
    Veraart C, Wanet-Defalque MC, Gerard B, et al. (2003) Pattern recognition with the optic nerve visual prosthesis. Artif Organs11:996–1004Google Scholar
  69. 69.
    Brelen ME, De Potter P, Gersdorff M, et al. (2006) Intraorbital implantation of a stimulating electrode for an optic nerve visual prosthesis, case report. J Neurosurg 104:593–597Google Scholar
  70. 70.
    Fang X, Sakaguchi H, Fujikado T (2005) Direct stimulation of optic nerve by electrodes implanted in optic disc of rabbit eyes. Graefe’s Arch Clin Exp Ophthalmol 243:49–56Google Scholar
  71. 71.
    Nichols MF (1994) The challenges for hermetic encapsulation of implanted devices – A review. Biomed Eng 22:39–67Google Scholar
  72. 72.
    Babak Z, Von Arx JA, Dokmeci MR, et al. (1996) A hermetic glass-silicon micropackage with high- density on-chip feedthroughs for sensors and actuators. J Microelectromech Syst 5:166–177Google Scholar
  73. 73.
    Kanda Y, Aoshinma R, Takada A (1981) Blood compatibility of components and materials in silicon integrated circuits. Electron Lett 17:558–559Google Scholar
  74. 74.
    Yuen T, Agnew W, Bullara L, et al. (1990) Biocompatibility of electrodes and materials in the central nervous system. In: Agnew W, McCreery D (eds) Neural prostheses: Fundamental studies. Prentice Hall, Englewood Cliffs, NJ, pp 171–321Google Scholar
  75. 75.
    Terasawa Y, Uehara A, Yonezawa E, et al. (2008) A visual prosthesis with 100 electrodes featuring wireless signals and wireless power transmission. IEICE Electron Express 5:574–580Google Scholar
  76. 76.
    Wong CP (1995) Recent advances in hermetic equivalent flip-chip hybrid IC packaging of Microelectronics. Mater Chem Phys 42:25–30Google Scholar
  77. 77.
    Stieglitz T, Haberer W, Lau C, et al. (2004) Development of an inductively coupled epiretinal visual prosthesis. Proceedings of the 26th Annul International Conference of the IEEE EMBS, San Francisco, pp 4178–4181Google Scholar
  78. 78.
    Rodger DC, Fong AJ, Li W, et al. (2008) Flexible parylene-based multielectrode array technology for high-density neural stimulation and recording. Sens Actuators B 132:449–460Google Scholar
  79. 79.
    Auciello O (2005) Science and Technology of Ultrananocrystalline Diamond Films as Hermetic Bioinert Coatings for Artificial Retina Microchip Encapsulation. Proceedings of the Second DOE International Symposium on Artificial Sight, April 29, 2005, Ft. Lauderdale, FloridaGoogle Scholar
  80. 80.
    Xiao X, Wang J, Liu C, et al. (2006) In vitro and in vivo evaluation of ultrananocrystalline diamond for coating of implantable retinal microchips. J Biomed Mater Res B: Appl Biomater 77:273–281Google Scholar
  81. 81.
    Zhou D, Mech B, Greenberg R (2000) Accelerated corrosion tests on Silicon wafers for implantable medical devices. Proceedings of the 198th Electrochemical Society Meeting, October, 2000, p 363Google Scholar
  82. 82.
    Meyer JU (2002) Retina implant – A bioMEMS challenge. Sens Actualors A-Phys 97–98:1–9Google Scholar
  83. 83.
    Montezuma S, Loewenstein J, Scholz C, et al. (2006) Biocompatibility of materials implanted into the subretinal space of Yucatan pigs. Invest Ophthal Vis Sci 47:3514–3522Google Scholar
  84. 84.
    Scholz C (2007) Perspectives on: Materials Aspects for Retinal Prostheses. J Bioact Compat Polym 22:539–568Google Scholar
  85. 85.
    Sweitzer R, Montezuma S, Rizzo J, et al. (2006) Evaluation of subretinal implants coated with amorphous aluminum oxide and diamond-like carbon. J Biodegradable Compat Polym 21:5–22Google Scholar
  86. 86.
    Cogan SF, Edell D, Guzelian A, et al. (2003) Plasma-enhanced chemical vapor deposited silicon carbide as an implantable dielectric coating. J Biomedical Mater Res A67:856–867Google Scholar
  87. 87.
    Xiao X, Wang J, Carlisle JA, et al. (2005) Ultrananocrystalline diamond as a hermetic, bio-inert coating for implantable medical devices. Proceeding of Materials Research Society Meeting, March 28–April 1, 2005, San FranciscoGoogle Scholar
  88. 88.
    Liu W, Sivaprakasam M, Wang G, et al. (2007) Challenges in realizing a chronic high-resolution retinal prosthesis. In: Humayun MS, et al. (Eds.) Artificial Sight, Basic Research, Biomedical Engineering, and Clinical Advances, Chapter 7, Springer, New York, pp 129–150Google Scholar
  89. 89.
    Shah S, Hines A, Zhou D, et al. (2007) Electrical properties of retinal-electrode interface. J Neural Eng 4:S24–S29Google Scholar
  90. 90.
    Piyathaisere DV, Eyal M, Chen S, et al. (2003) Heat effects on the retina. Ophthalmic Surg Lasers Imaging 34:114–120Google Scholar
  91. 91.
    Gosalia K, Weiland J, Humayun M, et al. (2004) Thermal elevation in the human eye and head due to the operation of a retinal prosthesis. IEEE Trans Biomed Eng 51:1469–1477Google Scholar
  92. 92.
    Klomp GF, Womack MV, Dobelle WH (1977) Fabrication of large arrays of cortical electrodes for use in man. J Biomed Mater Res 11:347–364Google Scholar
  93. 93.
    McCreery D, Lossinsky A, Pikov V, et al. (2006) Microelectrode array for chronic deep-brain microstimulation and recording. IEEE Trans Biomed Eng 53(4):726–737Google Scholar
  94. 94.
    Kim ET, Seo JM, Se Woo SJ, et al. (2008) Fabrication of pillar shaped electrode arrays for artificial retinal implants. Sensors 8:5845–5856Google Scholar
  95. 95.
    Gerding H, Ezelius H, Niggemann B (2006) The minimal invasive Retinal Implant (miRI) project: a novel approach towards the restoration of vision in patients with degenerative retinal diseases (ARVO abstract 3214)Google Scholar
  96. 96.
    Majji A, Humayun M, Weiland J, et al. (1999) Long-term histological and electrophysiological results of an inactive epiretinal electrode array implantation in dogs. Invest Ophthalmol Vis Sci 40:2073–2081Google Scholar
  97. 97.
    Yanai D, Weiland JD, Mahadevappa M, et al. (2007) Visual performance using a retinal prosthesis in three subjects with retinitis pigmentosa. Amer J Ophthalmol 143:820–827Google Scholar
  98. 98.
    Hesse L, Schanze T, Wilms M, et al. (2000) Implantation of retina stimulation electrodes and recording of electrical stimulation responses in the visual cortex of the cat. Graefe’s Arch Clin Exp Ophthalmol 238:840–845Google Scholar
  99. 99.
    Stieglitz T, Beutel H, Schuettler M, et al. (2000) Micromachined, polyimide-based devices for flexible neural interfaces. Biomed Microdevices 2:283–294Google Scholar
  100. 100.
    Sachs HG, Gabel V (2004) Retinal replacement-the development of microelectronic retinal prostheses experience with subretinal implants and new aspects. Graefe’s Arch Clin Exp Ophthalmol 242:717–723Google Scholar
  101. 101.
    Rodger DC, Weiland JD, Humayun MS, et al. (2006) Scalable high lead-count parylene package for retinal prostheses. Sens actuators B Chem 117:107–114Google Scholar
  102. 102.
    Rodger DC, Li W, Ameri H (2007) Dual-metal-layer parylene-based flexible electrode arrays for intraocular retinal prostheses. Invest Ophthalmol Vis Sci 48:E-Abstract 657Google Scholar
  103. 103.
    Terasawa Y, Tashiro H, Uehara A (2006) The development of a multichannel electrode array for retinal prostheses. J Artif Organs 9:263–266Google Scholar
  104. 104.
    Cui X, Zhou D (2007) Poly(3,4-ethylenedioxythiophene) for chronic neural stimulation. IEEE Trans Neural Syst Rehabil Eng 15:502–508Google Scholar
  105. 105.
    Weiland JD, Liu WT, Humayan MS (2005) Retinal Prosthesis. Annu Rev Biomed Eng 7:361–401Google Scholar
  106. 106.
    Rose TL, Kelliher EM, Robblee LS (1985) Assessment of capacitor electrodes for intracortical neural stimulation. J Neurosci Methods 12:181–193Google Scholar
  107. 107.
    Guyton DL, Hambrecht FT (1974) Theory and design of capacitor electrodes for chronic stimulation. Med Biol Eng 9:613–620Google Scholar
  108. 108.
    Zhou D, Greenberg, R (2001) Tantalum capacitive microelectrode array for neural prosthesis. In: Butler M, Vanysek P, Yamazoe N (eds) Chemical and biological sensors and analytical methods II. Electrochemical Society, Pennington, New Jersey, pp 622–629Google Scholar
  109. 109.
    Janders M, Egert U, Stelzle M, et al. (1996) Novel thin film titanium nitride micro-electrodes with excellent charge transfer capability for cell stimulation and sensing applications. 18th Annual international Conference of the IEEE Engineering in medicine and biology society, Amsterdam, pp 245–247Google Scholar
  110. 110.
    Schaldach M, Hubmann M, Weikl A, et al. (1990) Sputter-deposited TiN electrode coatings for superior sensing and pacing performance. Pace 3:1891–1895Google Scholar
  111. 111.
    Meyer JU, Stieglitz T, Scholz O, et al. (2001) High density interconnects and flexible hybrid assemblies for active biomedical implants. IEEE Trans Adv Packging 24:366–374Google Scholar
  112. 112.
    Guenther E, Troger B, Schlosshauer B, et el. (1999) Long-term survival of retinal cell cultures on retinal implant materials. Vision Res 39:3988–3994Google Scholar
  113. 113.
    Zhou D, Greenberg R (2003) Electrochemical Characterization of Titanium Nitride Microelectrode Arrays for Charge-Injection Applications. Proceedings of 25th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Cancun, paper1.2.4-1 (CD ROM)Google Scholar
  114. 114.
    Cogan SF (2008) Neural Stimulation and Recording Electrodes. Annu Rev Biomed Eng 10:14.1–14.35Google Scholar
  115. 115.
    Cogan SF, Guzelian AA, Agnew WF, et al. (2004) Over-pulsing degrades activated iridium oxide films used for intracortical neural stimulation. J Neurosci Methods 137:141–150Google Scholar
  116. 116.
    Cogan SF, Troyk RP, Ehrlich J, et al. (2005) In vitro comparison of the charge-injection limits of activated iridium Oxide (AIROF) and Platinum-Iridium Microelectrodes. IEEE Trans Biomed Eng 52:1612–1614Google Scholar
  117. 117.
    Zhou D (2005) Platinum electrode and method for manufacturing the same. US Patent 6,974,533Google Scholar
  118. 118.
    Hung A, Zhou D, Greenberg R, et al. (2002) Micromachined Electrodes for High Density Neural Stimulation Systems, 2nd Annual International, IEEE-EMBS Special Topic Conference on Microtechnologies in Medicine & Biology, Madison, Wisconsin, pp 76–79Google Scholar
  119. 119.
    Zhou D, Greenberg R (2005) Microsensors and microbiosensors for retinal implants. Front Biosci 10:166–179Google Scholar
  120. 120.
    Walter P, Szurman P, Vobig M, et al. (1999) Successful long-term implantation of electrically inactive epiretinal microelectrode arrays in rabbits. Retina 19:546–552Google Scholar
  121. 121.
    Margalit E, Fujii GY, Lai JC, et al. (2000) Bioadhesives for intraocular use. Retina 20:469–477Google Scholar
  122. 122.
    Taneri S, Bollmann FP, Uhlig C, et al. (1999) The retina implant—project: in vitro and in vivo testing of different tack types for intraocular fixation of retina implants Invest. Ophthalmol Vis Sci 40:733Google Scholar
  123. 123.
    Berk H, Vobig M, Walter P, et al. (1999) Long-term visual function after tach fixation of epiretinal stimulators in rabbits. IOVS 40:S732Google Scholar
  124. 124.
    Sachs HG, Schanze T, Wilms M, et al. (2004) Subretinal implantation and testing of polyimide film electrodes in cats. Graefe’s Arch Clin Exp Ophthalmol 243:464–468Google Scholar
  125. 125.
    McMahon MJ, Caspi A, Dorn JD, et al. (2007) Spatial vision in blind subjects implanted with the Second Sight retinal prosthesis. Invest Ophthalmol Vis Sci 48:E-Abstract 4443.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Second Sight Medical Products, Inc., Sylmar Biomedical Park, SylmarUSA
  2. 2.Second Sight Medical Products, Inc., Sylmar Biomedical ParkSylmarUSA

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