Analysis of Electrically Evoked Potential in Rabbits with Polyimide Retinal Stimulator

PURPOSE: Electrically evoked potential (EEP) was recorded in rabbits with polyimide-based, multichannel, microelectrode array (MEA) in their eyes, and was compared with the visual evoked potential (VEP) by flash light. METHODS: VEP was recorded under full-field flash light stimulation by 0. 6 J at 2 Hz, while EEP was recorded under electrical current stimulation of the retina by MEA. Latencies and shapes of N1, P100 and N2 in each evoked potential were compared. RESULTS: EEP was recorded in four of six rabbits. N1, P100 and N2 were observed in EEP on the electrical retina stimulation over 2.5 mA, and they resembled those of VEP. However, N1, P100 and N2 of EEP showed shorter latencies than those of VEP, by 15.1 msec (32.9%), 76.8 msec (38.3%) and 99.7 msec (60.1%) respectively. CONCLUSIONS: EEP by electrical retina stimulation with MEA was similar to VEP, indicating that MEA is suitable for the development of the artificial retina prototype. The shorter latencies of EEP should be considered in the parameters of the electrical stimulation of the retina.

Artificial Retina Mimbrane Assembly Utilzing Intelligent Materials: Biocompatibility and Electorphysiologic Features

In recent studies there have been various attempts at replacing a damaged retina with an artificial one. This paper outlines the assembly of an artificial retina membrane by incorporating a photorective protein bacteriorhodopsin into an electrochemically syntheszed conducting polymer polypyrrole. An electrophysiologic test was conducted to evaluate the photoresponsiveness of the bacteriorhodopsin and rabbit eyes were used to examine the biocompatibility of the artificial retina. The electrophysiologic test analyzed both wave forms and amplitudes obtained by photostimulating the artificial retina membrane with various light intensites(0.2, 2, 20J). In the biocompatibility test, the artificial membrane was inserted into the anterior chambers(4 eyes) and vitreous cavities(8 eyes) of rabbits. The condition of the eyes was then observed for one month. At the end of the first moonth, the eyes were enucleated and a histological examination was carried out. The electrophysiologic study displayed negative reflection waves, which are characteristic in rhodpsin, and their amplitudes showed a correspondign increase with stronger light intensities. The results of the biocompatibility test demonstrated that inflammatory reactions were not prominent in either the anterior chambers or the vitreous cavities during the first month and the histological examinations revealed no specific findings. In conclusion, a membrane assembled utilizing an electroactive polymer and a phocial retina.

The latest development of artificial vision technology / 医疗卫生装备

The latest domestic and foreign development of artificial vision technology is introduced in this paper. Its prospect and feasibility in China are mentioned too.