May 2006
Volume 47, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2006
Retinal Migration Into 3–Dimensional Subretinal Prosthetic Implants
Author Affiliations & Notes
  • P. Huie
    Stanford, Stanford, CA
    Ophthalmology and Hansen Exptl. Physics Lab,
  • I. Chan
    Stanford, Stanford, CA
    Ophthalmology,
  • A. Vankov
    Stanford, Stanford, CA
    Ophthalmology and Hansen Exptl. Physics Lab,
  • A. Butterwick
    Stanford, Stanford, CA
    Hansen Exptl. Physics Lab,
  • M. Marmor
    Stanford, Stanford, CA
    Ophthalmology,
  • M.S. Blumenkranz
    Stanford, Stanford, CA
    Ophthalmology,
  • B.W. Jones
    Moran Eye Center, University of Utah, UT
  • D. Palanker
    Stanford, Stanford, CA
    Ophthalmology and Hansen Exptl. Physics Lab,
  • Footnotes
    Commercial Relationships  P. Huie, VISX Inc., P; I. Chan, None; A. Vankov, VISX Inc., P; A. Butterwick, None; M. Marmor, None; M.S. Blumenkranz, VISX Inc., P; B.W. Jones, None; D. Palanker, VISX Inc., P.
  • Footnotes
    Support  AFOSR grant F9550–04–1–0075
Investigative Ophthalmology & Visual Science May 2006, Vol.47, 3215. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      P. Huie, I. Chan, A. Vankov, A. Butterwick, M. Marmor, M.S. Blumenkranz, B.W. Jones, D. Palanker; Retinal Migration Into 3–Dimensional Subretinal Prosthetic Implants . Invest. Ophthalmol. Vis. Sci. 2006;47(13):3215.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose: : High spatial resolution of retinal stimulation requires close proximity of electrodes to the target cells. Placement of flat prosthetic implants epiretinally or subretinally typically results in a separation from target cells by several tens of µm. Much closer proximity would be achieved if one could promote retinal migration into the interstices of subretinal implants that have cavities or closely spaced pillars facing the retinal tissue.

Methods: : 3–dimensional arrays having either chambers with apertures of 10–15 µm in width or pillars of 10 µm in diameter were fabricated lithographically using UV–sensitive polymers. The depth of the chambers and the height of the pillars could be adjusted and was kept within a range of 40 – 70 µm. A special surgical tool has been developed for safe insertion of the implant into the subretinal space through a scleral incision. Implantations into the RCS rats were performed after the complete degeneration of the photoreceptors (45–65 days of age). Histological analysis has been performed in 18 rats 2 and 6 weeks post–operatively.

Results: : Intimate proximity between stimulation sites and cells in the inner nuclear layer has been achieved using both the chamber and pillar arrays. Complete and non–traumatic penetration of the pillars into the inner nuclear layer has been observed with a pixel density up to 2500 pix/mm2 (center–to–center pillar spacing of 20 µm). A wet implantation technique that involves injection of liquid into the subretinal space prior to insertion of the implant was found to be less traumatic than a dry technique. With wet implantation the retina tolerated the implant very well, including rapid (72 hours) migration of retinal cells into the implant and no fibrosis. Computational molecular phenotyping has shown that bipolar and amacrine cells in proximity to the implant maintain their normal molecular signatures, indicating normal metabolic status. Traumatic implantations (mostly dry) led to retinal edema and a fibrotic seal within 6 weeks, especially around the flat parts of the implant.

Conclusions: : Three–dimensional subretinal implants with pillars or cavities can take advantage of the intrinsic plasticity of the retina since neurite extension and migration bring retinal cellular components into close proximity of electrodes. This will allow a higher efficacy of stimulation. Atraumatic insertion of the implant is very important for assuring integration of the device with the retina and for avoiding a fibrotic seal.

Keywords: retinal connections, networks, circuitry 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×