PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 9775223

Artificial vision.

M S Humayun·E de Juan
View original source ↗Export metadata ↓

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).

Explore related subjects

BlindnessColor PerceptionElectric Stimulation TherapyForm PerceptionHumansMicroelectrodesPhosphenesRetinal DegenerationRetinitis PigmentosaJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M S Humayun, E de Juan. 1998. Artificial vision.. https://doi.org/10.1038/eye.1998.151

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2001

Unseen stimuli modulate conscious visual experience: evidence from inter-hemispheric summation.

Emotional facial expression can be discriminated despite extensive lesions of striate cortex. Here we report differential performance with recognition of facial stimuli in the intact visual field depending on simultaneous presentation of congruent or incongruent stimuli in the blind field. Three experiments were based on inter-hemispheric summation. Redundant stimulation in the blind field led to shorter latencies for stimulus detection in the intact field. Recognition of the expression of a half-face expression in the intact field was faster when the other half of the face presented to the blind field had a congruent expression. Finally, responses to the expression of whole faces to the intact field were delayed for incongruent facial expressions presented in the blind field. These results indicate that the neuro-anatomical pathways (extra-striate cortical and sub-cortical) sustaining inter-hemispheric summation can operate in the absence of striate cortex.

Blindness↗
PubMed2001

Gaze-evoked amaurosis produced by intraorbital buckshot pellet.

OBJECTIVE: To report the first case of gaze-evoked amaurosis secondary to an intraocular foreign body and to highlight the characteristic clinical findings of patients with this symptom. DESIGN: Case report and review of the literature. METHODS: Case review, clinical history, electrophysiologic testing, and follow-up. MAIN OUTCOME MEASURES: Visual acuity, automated perimetry, and visual fields. RESULTS: A case of gaze-evoked amaurosis as a result of an intraorbital foreign body is described, and 19 additional cases of gaze-evoked amaurosis are reviewed from the English language literature. These cases share certain characteristics including good vision in primary position with deterioration of vision in eccentric gaze; concurrent objective pupillary abnormalities in eccentric gaze; stereotypic onset and recovery of vision; and funduscopic abnormalities consisting of disc edema and chorioretinal folds. CONCLUSIONS: Gaze-evoked amaurosis is a reliable sign of intraconal mass lesion. We report the first case of gaze-evoked amaurosis secondary to an intraorbital foreign body.

Blindness↗