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Implantation of silicon chip microphotodiode arrays into the cat subretinal space.

Abstract

There are currently no therapies to restore vision to patients blinded by photoreceptor degeneration. This project concerns an experimental approach toward a semiconductor-based subretinal prosthetic designed to electrically stimulate the retina. The present study describes surgical techniques for implanting a silicon microphotodiode array in the cat subretinal space and subsequent studies of implant biocompatibility and durability. Using a single-port vitreoretinal approach, implants were placed into the subretinal space of the right eye of normal cats. Implanted retinas were evaluated post-operatively over a 10 to 27 month period using indirect ophthalmoscopy, fundus photography, electroretinography, and histology. Infrared stimulation was used to isolate the electrical response of the implant from that of the normal retina. Although implants continued to generate electrical current in response to light, the amplitude of the implant response decreased gradually due to dissolution of the implant's gold electrode. Electroretinograms recorded from implanted eyes had normal waveforms but were typically 10-15% smaller in amplitude than those in unimplanted left eyes. The nonpermeable silicon disks blocked choroidal nourishment to the retina, producing degeneration of the photoreceptors. The laminar structure of the inner retinal layers was preserved. Retinal areas located away from the implantation site appeared normal in all respects. These results demonstrate that silicon-chip microphotodiode-based implants can be successfully placed into the subretinal space. Gold electrode-based subretinal implants, however, appear to be unsuitable for long-term use due to electrode dissolution and subsequent decreased electrical activity.

Authors+Show Affiliations

Optobionics Corporation, Wheaton, IL 60187, USA. alanykc@aol.comNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

11482368

Citation

Chow, A Y., et al. "Implantation of Silicon Chip Microphotodiode Arrays Into the Cat Subretinal Space." IEEE Transactions On Neural Systems and Rehabilitation Engineering : a Publication of the IEEE Engineering in Medicine and Biology Society, vol. 9, no. 1, 2001, pp. 86-95.
Chow AY, Pardue MT, Chow VY, et al. Implantation of silicon chip microphotodiode arrays into the cat subretinal space. IEEE Trans Neural Syst Rehabil Eng. 2001;9(1):86-95.
Chow, A. Y., Pardue, M. T., Chow, V. Y., Peyman, G. A., Liang, C., Perlman, J. I., & Peachey, N. S. (2001). Implantation of silicon chip microphotodiode arrays into the cat subretinal space. IEEE Transactions On Neural Systems and Rehabilitation Engineering : a Publication of the IEEE Engineering in Medicine and Biology Society, 9(1), pp. 86-95.
Chow AY, et al. Implantation of Silicon Chip Microphotodiode Arrays Into the Cat Subretinal Space. IEEE Trans Neural Syst Rehabil Eng. 2001;9(1):86-95. PubMed PMID: 11482368.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Implantation of silicon chip microphotodiode arrays into the cat subretinal space. AU - Chow,A Y, AU - Pardue,M T, AU - Chow,V Y, AU - Peyman,G A, AU - Liang,C, AU - Perlman,J I, AU - Peachey,N S, PY - 2001/8/3/pubmed PY - 2002/1/5/medline PY - 2001/8/3/entrez SP - 86 EP - 95 JF - IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society JO - IEEE Trans Neural Syst Rehabil Eng VL - 9 IS - 1 N2 - There are currently no therapies to restore vision to patients blinded by photoreceptor degeneration. This project concerns an experimental approach toward a semiconductor-based subretinal prosthetic designed to electrically stimulate the retina. The present study describes surgical techniques for implanting a silicon microphotodiode array in the cat subretinal space and subsequent studies of implant biocompatibility and durability. Using a single-port vitreoretinal approach, implants were placed into the subretinal space of the right eye of normal cats. Implanted retinas were evaluated post-operatively over a 10 to 27 month period using indirect ophthalmoscopy, fundus photography, electroretinography, and histology. Infrared stimulation was used to isolate the electrical response of the implant from that of the normal retina. Although implants continued to generate electrical current in response to light, the amplitude of the implant response decreased gradually due to dissolution of the implant's gold electrode. Electroretinograms recorded from implanted eyes had normal waveforms but were typically 10-15% smaller in amplitude than those in unimplanted left eyes. The nonpermeable silicon disks blocked choroidal nourishment to the retina, producing degeneration of the photoreceptors. The laminar structure of the inner retinal layers was preserved. Retinal areas located away from the implantation site appeared normal in all respects. These results demonstrate that silicon-chip microphotodiode-based implants can be successfully placed into the subretinal space. Gold electrode-based subretinal implants, however, appear to be unsuitable for long-term use due to electrode dissolution and subsequent decreased electrical activity. SN - 1534-4320 UR - https://www.unboundmedicine.com/medline/citation/11482368/Implantation_of_silicon_chip_microphotodiode_arrays_into_the_cat_subretinal_space_ L2 - https://dx.doi.org/10.1109/7333.918281 DB - PRIME DP - Unbound Medicine ER -