There are opthalmological conditions such as Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP) in which the photoreceptors in the retina are destroyed . However, work done by Stone, et.al.,  showed that between 30% and 80% of the retinal ganglion cells, and other cells of the inner nuclear layer, are still viable and functional. If this is the case than it may be possible to bypass the natural photoreceptor process and directly stimulate all or some of these ganglion cells in order to restore vision, to some degree.
There are several projects going on around the world aiming at creating a retinal prosthesis of sorts [3 -9]. Some projects seek to implant electronic devices either on the vitreous side of the retina (epiretinal), inside the retina at the level of Bruch's membrane (sub-retinal), and some seek to implant a device on the brain (cortical). The AeRP is an epiRetinal device that rests "on" the retina in order to stimulate any healthy RGC.
The first Figure is the AeRP Internal View, with an exaggerated radius cataract replacement lens. Lens, Fiber Optic Plate, Fiber Optic Strand Bundles, Holders and Small Photodiode Cylinder.
The second Figure is the AeRP External View, with an exaggerated radius cataract replacement lens. AeRP with Lead Umbrella Assembly.
The AeRP in the eye