Subretinal stimulation of the retina with neurotransmitters, the normal means of conveying visual information, is a potentially better alternative to electrical stimulation widely used in current retinal prostheses for treating blindness from photoreceptor degenerative diseases. Yet, no subretinal electrical or chemical stimulation study has stimulated the OFF and ON pathways differentially thr...

PURPOSE To determine whether the sustained intravitreous delivery of CNTF modulates cortical response thresholds to electrical retinal stimulation in the RCS rat model of retinal degeneration. METHODS Animals were assigned to four groups: untreated, nonsurgical control and infusion groups of 10 ng/d CNTF, 1 ng/d CNTF, and PBS vehicle control. Thresholds for electrically evoked cortical potent...

Abstract Implantable retinal prostheses are stimulation devices used to compensate for the light sensitivity loss of cells. In this study, we propose and demonstrate a novel method significantly reduce setting time conditions prosthesis chip capable multi-electrode stimulation. The efficiency control is increased while using only two wires, as in our previous work. comprises an 8 bit ID 7 elect...

BACKGROUND Microelectrode array (MEA) devices are frequently used in neural circuit studies, especially in retinal prosthesis. For a high throughput stimulation and recording paradigm, it is desirable to obtain the responses of multiple surface RGCs initiated from the electrical signals delivered to multiple photoreceptor cells. This can be achieved by an high density MEA-tissue-MEA (MTM) sandw...

OBJECTIVE One strategy to improve the effectiveness of prosthetic vision devices is to process incoming images to ensure that key information can be perceived by the user. This paper presents the first comprehensive results of vision function testing for a suprachoroidal retinal prosthetic device utilizing of 20 stimulating electrodes. Further, we investigate whether using image filtering can i...

Promising new research measuring the properties of series photodiode circuits has shown that they may be suitable for retinal prosthesis [1]. Photodiode arrays, in order to be effective in this capacity, must be pulsed with infrared light (∼900nm) at a much higher intensity than ambient light. The light must be infrared for this particular application because light in the visible spectrum may d...

This work was undertaken to contribute to the development of an epi-retinal prosthesis which may someday restore vision to patients blinded by outer retinal degenerations like retinitis pigmentosa. By stimulating surviving cells in tens or hundreds of distinct regions across the retinal surface, the prosthesis might convey the visual scene in the same way that images are represented on a comput...

A blind volunteer with retinitis pigmentosa was chronically implanted with a self-sizing spiral cuff electrode around an optic nerve. Electrical stimuli applied to the nerve produced localized visual sensations that were broadly distributed throughout the visual field and could be varied by changing the stimulating conditions. These results demonstrate the potential for constructing a visual pr...

Retinal prostheses aim to restore functional vision to those blinded by outer retinal diseases using electric stimulation of surviving retinal neurons. The ability to replicate the spatiotemporal pattern of ganglion cell spike trains present under normal viewing conditions is presumably an important factor for restoring high-quality vision. In order to replicate such activity with a retinal pro...

PURPOSE To demonstrate local cortical activations in the primary visual cortex of the cat as a result of retinal electrical stimulation by means of a completely wireless-controlled, implantable retinal prosthesis in a series of acute experiments. METHODS The transfer of energy to drive the device and signals to activate any combination of 25 retinal electrodes was achieved completely wireless...