Artificial vision
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Updated: Oct 28, 2026

Functional Magnetic Resonance Imaging (fMRI) of the Visual Cortex with Wide-View Retinotopic Stimulation
Published on: December 8, 2023
1Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD 21287, USA. mhumayan@gwgate1.jhmi.jhu.edu
Abstract:
Outer retinal degenerations such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD) lead to blindness because of photoreceptor degeneration. To test whether controlled electrical stimulation of the remaining retinal neurons could provide form vision, we electrically stimulated the inner retinal surface with micro-electrodes inserted through the sclera/eye wall of 14 of these patients (12 RP and 2 AMD). This procedure was performed in the operating room under local anaesthesia and all responses were recorded via a video camera mounted on the surgical microscope. Electrical stimulation of the inner retinal surface elicited visual perception of a spot of light (phosphene) in all subjects. This perception was retinotopically correct in 13 of 14 patients. In a resolution test in a subject with no light perception, the patient could resolve phosphenes at 1.75 degrees centre-to-centre distance (i.e. visual acuity compatible with mobility; Snellen visual acuity of 4/200).
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