TY - JOUR
T1 - Electrophysiological and histological studies of chronically implanted intrapapillary microelectrodes in rabbit eyes
AU - Fang, Xiaoyun
AU - Sakaguchi, Hirokazu
AU - Fujikado, Takashi
AU - Osanai, Makoto
AU - Ikuno, Yasushi
AU - Kamei, Motohiro
AU - Ohji, Masahito
AU - Yagi, Tetsuya
AU - Tano, Yasuo
N1 - Funding Information:
Acknowledgements This study was supported by a grant (no. 14571670) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
PY - 2006/3
Y1 - 2006/3
N2 - Purpose: To determine the safety and efficacy of transsclerally placed intrapapillary wire microelectrodes implanted chronically into the optic nerve head of rabbit eyes. Methods: Four platinum wire microelectrodes were passed through the sclera and implanted into the optic nerve head of five rabbit eyes for 4-6 months. Color fundus photography, fluorescein angiography, electroretinograms (ERGs), and visually evoked potentials (VEPs) were used to monitor the retina. Electrically evoked potentials (EEPs) were elicited by bipolar electrical stimulation of the optic nerve axons by different combinations of the four electrodes immediately after the implantation and at 1-month intervals thereafter. The effects of the chronic implantation of the electrodes on the morphology of the optic nerve were evaluated by histological and immunohistochemical examinations at 4 and 6 months after the implantation. Results: All of the electrodes remained stable in the implanted sites throughout the post-implantation period, except for one electrode that had pulled out of the optic nerve head at 1 month after implantation. No intraocular infection, inflammation, or vitreoretinal proliferation was observed in any eye. EEPs could be elicited from each pair of electrodes at all testing times. The mean threshold currents (charge densities) to evoke EEPs increased from 19.3±9.2 μA (6.0±2.9 μC/ cm2) on the implantation day to 78.8±31.9 μA (24.6±10.0 μC/cm2) at 1 month after implantation, but did not change significantly thereafter. The implicit time and amplitude of the a- and b-waves of the ERGs and of P1 of the VEPs did not change significantly throughout the post-implantation period. Histological evaluation of the optic nerve head revealed slight tissue encapsulations surrounding the electrode and increased expression of glial fibrillary acidic protein near the surface of the optic nerve. Conclusions: Implantation of transscleral intrapapillary microelectrodes appears to be safe and effective. These findings indicate that the implantation of microelectrodes in the optic nerve head should be considered for an optic nerve-based prosthesis.
AB - Purpose: To determine the safety and efficacy of transsclerally placed intrapapillary wire microelectrodes implanted chronically into the optic nerve head of rabbit eyes. Methods: Four platinum wire microelectrodes were passed through the sclera and implanted into the optic nerve head of five rabbit eyes for 4-6 months. Color fundus photography, fluorescein angiography, electroretinograms (ERGs), and visually evoked potentials (VEPs) were used to monitor the retina. Electrically evoked potentials (EEPs) were elicited by bipolar electrical stimulation of the optic nerve axons by different combinations of the four electrodes immediately after the implantation and at 1-month intervals thereafter. The effects of the chronic implantation of the electrodes on the morphology of the optic nerve were evaluated by histological and immunohistochemical examinations at 4 and 6 months after the implantation. Results: All of the electrodes remained stable in the implanted sites throughout the post-implantation period, except for one electrode that had pulled out of the optic nerve head at 1 month after implantation. No intraocular infection, inflammation, or vitreoretinal proliferation was observed in any eye. EEPs could be elicited from each pair of electrodes at all testing times. The mean threshold currents (charge densities) to evoke EEPs increased from 19.3±9.2 μA (6.0±2.9 μC/ cm2) on the implantation day to 78.8±31.9 μA (24.6±10.0 μC/cm2) at 1 month after implantation, but did not change significantly thereafter. The implicit time and amplitude of the a- and b-waves of the ERGs and of P1 of the VEPs did not change significantly throughout the post-implantation period. Histological evaluation of the optic nerve head revealed slight tissue encapsulations surrounding the electrode and increased expression of glial fibrillary acidic protein near the surface of the optic nerve. Conclusions: Implantation of transscleral intrapapillary microelectrodes appears to be safe and effective. These findings indicate that the implantation of microelectrodes in the optic nerve head should be considered for an optic nerve-based prosthesis.
KW - Electrical stimulation
KW - Electrically evoked potential
KW - Electrode
KW - Histology
KW - Optic nerve head
KW - Visual prosthesis
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U2 - 10.1007/s00417-005-0073-9
DO - 10.1007/s00417-005-0073-9
M3 - Article
C2 - 16079995
AN - SCOPUS:33646261657
VL - 244
SP - 364
EP - 375
JO - Albrecht von Graefes Archiv für Klinische und Experimentelle Ophthalmologie
JF - Albrecht von Graefes Archiv für Klinische und Experimentelle Ophthalmologie
SN - 0065-6100
IS - 3
ER -