Retinitis Pigmentosa (RP) is a genetic disease resulting in irreversible photoreceptor cell death. Initially, only rods are affected, but their degeneration leads to a secondary loss of cones, even if they are genetically unaffected, leading to complete blindness.
Subretinal prostheses are electronic devices that, once implanted in the eye, may allow blind people to see through the electrical stimulation of the retina at the level of the degenerated photoreceptors (d-Phrs).
The Haq group in the Zrenner Lab is working on experimental retinal prosthetics, developing a new electrical stimulation paradigm in ex-vivo retina of mouse models for retinal degeneration.
In this paper, a novel concept of interfacing the retina using electrical implants was investigated to examine the potential of the degenerated photoreceptors (d-Phrs) for restoring visual responses once they are electrically stimulated in subretinal configuration and to estimate the optimal chip implantation phase during RP.
For that purpose, the surviving d-Phrs of the rd1 mouse (RP model) were electrically activated subretinally and both their activity (Ca2+-imaging) and the underlying ganglion cells (GC) (MEA-recording) were simultaneously recorded, showing that the d-Phrs respond to e-stimulation and modulate the retinal network-activity.
This study suggests that d-Phrs are the ideal interface partners for implants and the retina’s intact circuity at the onset of complete blindness recommends early implantation of a subretinal chip to provide a seamless vision aid.
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Fig. 1. Subretinal e-stimulation of the rd1 mouse retina and recordings.