BACKGROUND: Subretinal implants intend to replace photoreceptor function in patients suffering from degenerative retinal disease by topically applying electrical stimuli from the subretinal space. This study intended to prove the feasibility of a newly developed transchoroidal surgery and, furthermore, of a subretinal electrode array, which closely resembles envisioned human implants to electrically stimulate the visual system in rabbits. METHODS: Five rabbits (ten eyes) were implanted with a 4x2-electrode array via a transchoroidal access to the subretinal space. The electrodes were connected to an arbitrary stimulus generator to apply voltage pulses. Retinae were accessed by light microscopy after stimulation with various intensities. RESULTS: The stimulating foil could be introduced into the subretinal space in all eyes. In seven of ten eyes electrically evoked cortical potentials following subretinal electrical stimulation could be elicited. Threshold voltages ranged from less than 0.1 to 2.38 V with a corresponding threshold charge of approximately 1.0 nC per electrode or 10 micro C/cm(2). Histology revealed localized retinal damage over some of the electrodes succeeding stimulation strengths of 2 V and consistent damage over all electrodes succeeding voltages of 3 V. CONCLUSIONS: The study demonstrates the feasibility of the transchoroidal surgical access to place subretinal implants in rabbit eyes and provides proof of successful cortical activation following subretinal electrical stimulation by an electrode array envisioned for human implantations.
BACKGROUND: Subretinal implants intend to replace photoreceptor function in patients suffering from degenerative retinal disease by topically applying electrical stimuli from the subretinal space. This study intended to prove the feasibility of a newly developed transchoroidal surgery and, furthermore, of a subretinal electrode array, which closely resembles envisioned human implants to electrically stimulate the visual system in rabbits. METHODS: Five rabbits (ten eyes) were implanted with a 4x2-electrode array via a transchoroidal access to the subretinal space. The electrodes were connected to an arbitrary stimulus generator to apply voltage pulses. Retinae were accessed by light microscopy after stimulation with various intensities. RESULTS: The stimulating foil could be introduced into the subretinal space in all eyes. In seven of ten eyes electrically evoked cortical potentials following subretinal electrical stimulation could be elicited. Threshold voltages ranged from less than 0.1 to 2.38 V with a corresponding threshold charge of approximately 1.0 nC per electrode or 10 micro C/cm(2). Histology revealed localized retinal damage over some of the electrodes succeeding stimulation strengths of 2 V and consistent damage over all electrodes succeeding voltages of 3 V. CONCLUSIONS: The study demonstrates the feasibility of the transchoroidal surgical access to place subretinal implants in rabbit eyes and provides proof of successful cortical activation following subretinal electrical stimulation by an electrode array envisioned for human implantations.
Authors: E Zrenner; K D Miliczek; V P Gabel; H G Graf; E Guenther; H Haemmerle; B Hoefflinger; K Kohler; W Nisch; M Schubert; A Stett; S Weiss Journal: Ophthalmic Res Date: 1997 Impact factor: 2.892
Authors: John M Nickerson; Penny Goodman; Micah A Chrenek; Christiana J Bernal; Lennart Berglin; T Michael Redmond; Jeffrey H Boatright Journal: Methods Mol Biol Date: 2012
Authors: Dimiter R Bertschinger; Evgueny Beknazar; Manuel Simonutti; Avinoam B Safran; José A Sahel; Serge G Rosolen; Serge Picaud; Joel Salzmann Journal: Graefes Arch Clin Exp Ophthalmol Date: 2008-08-16 Impact factor: 3.117
Authors: Aditi Ray; Leonardo Colodetti; James D Weiland; David R Hinton; Mark S Humayun; Eun-Jin Lee Journal: Brain Res Date: 2008-12-09 Impact factor: 3.252
Authors: John M Nickerson; Shannon E Getz; Jana T Sellers; Micah A Chrenek; Penny Goodman; Christiana J Bernal; Jeffrey H Boatright Journal: Methods Mol Biol Date: 2014