Artikel
Contrast sensitivity with a subretinal prosthesis and implications for efficient delivery of visual information
Suche in Medline nach
Autoren
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Georges Goetz
- HEPL, Stanford, USA; Electrical Engineering, Stanford, USA
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R. Smith
- SCIPP, University of California Santa Cruz, USA
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X. Lei
- Electrical Engineering, Stanford, USA
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L. Galambos
- Electrical Engineering, Stanford, USA
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T. Kamins
- Electrical Engineering, Stanford, USA
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K. Mathieson
- Institute of Photonics, University of Strathclyde, Glasgow, UK
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A. Sher
- SCIPP, University of California Santa Cruz, USA
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D. Palanker
- HEPL, Stanford, USA; Ophthalmology Stanford, USA
| Veröffentlicht: | 7. März 2016 |
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Gliederung
Text
Objective: To assess the contrast sensitivity of a degenerate retina stimulated by a subretinal prosthesis, and the impact of low contrast sensitivity on transmission of visual information.
Methods: We measure ex-vivo the full-field contrast sensitivity of healthy rat retina stimulated with white light, and the contrast sensitivity of degenerate rat retina stimulated with a subretinal prosthesis at 20Hz. We model and simulate the effects of eye movements on retinal ganglion cell (RGC).
Results: RGCs respond transiently to transient ON-sets, OFF-sets, and both ON- and OFF-sets of light over the implant. The fraction of cells with an OFF response decreases with age of the animal. Prosthetic vision exhibits reduced contrast sensitivity, with 65% contrast changes required to elicit responses, as compared to 3-7% changes required with visible light. The maximum number of action potentials elicited is at most half of its natural counterpart for the ON pathway. Our model predicts that contrast sensitivity of prosthetic vision is insufficient for triggering RGC activity by fixational eye movements.
Discussion: Contrast sensitivity of prosthetic vision is 10 times lower than normal, and dynamic range is two times below natural. Low contrast sensitivity and lack of OFF responses hamper delivery of visual information via a subretinal prosthesis.
Acknowledgements: DP: NIH (R01-EY-018608), DOD (W81XWH-15-1-0009), Stanford Spectrum fund. AS: BWF CASI, Pew Charitable Trusts Scholarship in the Biomedical Sciences. KM: SU2P.
