March 2012
Volume 53, Issue 14
Free
ARVO Annual Meeting Abstract  |   March 2012
Seeing With Subretinal Electronic Implants: Study in Ten Patients With Wireless Implant Alpha-IMS
Author Affiliations & Notes
  • Eberhart Zrenner
    Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
  • Karl-Ulrich Bartz-Schmidt
    Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
  • Florian Gekeler
    Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
  • Udo Greppmaier
    Retina Implant AG, Reutlingen, Germany
  • Stephanie Hipp
    Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
  • Gernot Hoertdoerfer
    Mobility Training, Tuebingen, Germany
  • Christoph Kernstock
    Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
  • Akos Kusnyerik
    Semmelweis University, Budapest, Hungary
  • Helmut Sachs
    Städtisches Klinikum Dresden-Friedrichstadt, Dresden, Germany
  • Katarina Stingl
    Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
  • Footnotes
    Commercial Relationships  Eberhart Zrenner, Retina Implant AG (F, I, P, R, S); Karl-Ulrich Bartz-Schmidt, Retina Implant AG (F); Florian Gekeler, Retina Implant AG (F, C, P); Udo Greppmaier, Retina Implant AG (E); Stephanie Hipp, Retina Implant AG (F); Gernot Hoertdoerfer, Retina Implant AG (F); Christoph Kernstock, Retina Implant AG (F); Akos Kusnyerik, Retina Implant AG (F); Helmut Sachs, Retina Implant AG (F); Katarina Stingl, Retina Implant AG (F)
  • Footnotes
    Support  Kerstan Foundation; Retina Implant AG;
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 6948. doi:
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      Eberhart Zrenner, Karl-Ulrich Bartz-Schmidt, Florian Gekeler, Udo Greppmaier, Stephanie Hipp, Gernot Hoertdoerfer, Christoph Kernstock, Akos Kusnyerik, Helmut Sachs, Katarina Stingl; Seeing With Subretinal Electronic Implants: Study in Ten Patients With Wireless Implant Alpha-IMS. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6948.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: : Subretinal microphotodiode arrays with 1.500 pixels are able to restore vision up to reading capability (Zrenner et al . Proc. R. Soc. B 2011, 278: 1489ff). Here we report about the first phase of a multicenter trial with the wireless implant Alpha-IMS (Retina Implant AG, Tübingen, Germany).

Methods: : Each of the 1500 subfoveal photodiodes within a 11 by 11 deg field controls an amplifier that, depending on the strength of the light, ejects currents onto bipolar cells via an electrode (Stett et al 1999). Power and control signals are supplied by inductivity via a subdermal retroauricular coil from which a subdermal cable leads to the eyeball. Ten patients have received the new implant since 2010 (average age 45.95±7.9; 5 males, 5 females). Function was tested by four procedures: 1. Monitor-based standardized tests with controlled conditions for testing light perception threshold, light localization and movement (Wilke et al. 2007), as well as grating acuity and Landolt C-rings (2 or 4 AFC); 2. Recognition tasks at a table setting with tableware and geometric objects; 3. Reading of letters; 4. Outdoor activity, observed either by staff members or reported by the patients. All tests were also conducted with the device swiched off as control.

Results: : In all ten patients the chip was at the desired subfoveal position except in two patients where it was slightly parafoveal. Proper chip function was proven by measuring chip output via electroretinography. All patients were able to perform the function tests except one where a loss of inner retina function was observed after surgery. Results in all other patients were: light perception: 9/9, light localization: 8/9; motion recognition 5/9; grating resolution 8/9 (up to 3,3 cycles/degree); Landolt C rings 2/9 (up to VA= 0,036); recognition of geometric objects 8/9; recognition of objects in table setup 8/9; Letter reading 4/9; clock hands reading 3/9; grey scale differentiation 6/9; improved outdoor mobility and activity 5/9. Patients reported numerous beneficial visual experiences in daily life with regained recognition of unknown objects, recognition of facial or clothes’ characteristics, moving objects in nature and traffic, improved self-sustaining actions (recognition of doors, door handles), recognition of small objects (glasses, telephone, stapler, washing basin, even dice and numbers of dots on dice), improved mobility.

Conclusions: : Careful psychophysical testing and patient daily-life reports show that the wireless Alpha-IMS implant restores useful visual abilities in blind RP-patients. Subretinal surgery for positioning chips subfoveally is safe and the multicenter part of the study has been started.

Clinical Trial: : http://www.clinicaltrials.gov NCT01024803

Keywords: retina • retinal degenerations: hereditary • perception 
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