Retinal degenerative diseases lead to blindness due to loss of the "image capturing" photoreceptor layer, while neurons in the "image processing" inner retinal layers are preserved to a large extent. Electronic retinal prostheses seek to restor sight by electrical pattern stimulation of surviving neurons. Very encouraging clinical results with the first retinal prostheses have been recently demonstrated. However, current implants are powered through inductive coils, requiring complex surgical methods to implant the coil-decoder-cable-array systems, which deliver energy to stimulating electrodes via intraocular cables. We developed a photovoltaic subretinal prosthesis, in which silicon photodiodes in each pixel directly convert pulsed near-infrared (NIR) images projected from video goggles into local electric currents to stimulate neurons. This system offers multiple advantages over other designs: due to wireless activation of the pixels in the implant the system is scalable to thousands of electrodes;it maintains the natural link between eye movements and image perception;the implantation is greatly simplified and modular design of the implant allows expanding the visual field by tiling;pillar electrodes allow cellular-scale proximity to the targe neurons. Such a versatile system could be used to address the divergent needs of patients with various forms of retinal degeneration. We have manufactured and tested the first generation of the implants. Photovoltaic arrays show long-term biocompatibility, and provide safe retinal stimulation upon illumination with NIR pulses in-vitro and in-vivo. We now seek to produce the implants designed for highest resolution and lowest stimulation thresholds, and protected by inert and biocompatible coatings for long-term implantations. To achieve these goals we will assess visual acuity and contrast sensitivity obtained with subretinal photovoltaic implants of different designs in-vitro and in-vivo in animals with normal and degenerate retinas. This project brings together a unique combination of engineers, neuroscientists and ophthalmologists to complete the development and evaluation of a high-resolution retinal prosthetic system designed specifically for achieving the functional levels of vision.

Public Health Relevance

Retinal degenerative diseases lead to blindness due to loss of the image capturing photoreceptor layer, while neurons in the image processing inner retinal layers are preserved to a large extent. We developed a photovoltaic subretinal prosthesis, in which photodiodes in each pixel directly convert pulsed near- infrared images projected from video goggles into local electric currents and stimulate neurons. This system is scalable to thousands of pixels, is easily implantable, and maintains the natural link between eye movements and image perception. This innovative design has the potential to addresses the divergent needs of patients with various forms of retinal degeneration.

Agency
National Institute of Health (NIH)
Type
Research Project (R01)
Project #
5R01EY018608-06
Application #
8691820
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Shen, Grace L
Project Start
Project End
Budget Start
Budget End
Support Year
6
Fiscal Year
2014
Total Cost
Indirect Cost
Name
Stanford University
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
City
Stanford
State
CA
Country
United States
Zip Code
94304
Lei, Xin; Kane, Sheryl; Cogan, Stuart et al. (2016) SiC protective coating for photovoltaic retinal prosthesis. J Neural Eng 13:046016
Lee, Dae Yeong; Lorach, Henri; Huie, Phil et al. (2016) Implantation of Modular Photovoltaic Subretinal Prosthesis. Ophthalmic Surg Lasers Imaging Retina 47:171-4
Goetz, G A; Palanker, D V (2016) Electronic approaches to restoration of sight. Rep Prog Phys 79:096701
Boinagrov, David; Lei, Xin; Goetz, Georges et al. (2016) Photovoltaic Pixels for Neural Stimulation: Circuit Models and Performance. IEEE Trans Biomed Circuits Syst 10:85-97
Lorach, Henri; Kung, Jennifer; Beier, Corinne et al. (2015) Development of Animal Models of Local Retinal Degeneration. Invest Ophthalmol Vis Sci 56:4644-52
Fransen, James W; Pangeni, Gobinda; Pyle, Ian S et al. (2015) Functional changes in Tg P23H-1 rat retinal responses: differences between ON and OFF pathway transmission to the superior colliculus. J Neurophysiol 114:2368-75
Lorach, Henri; Goetz, Georges; Mandel, Yossi et al. (2015) Performance of photovoltaic arrays in-vivo and characteristics of prosthetic vision in animals with retinal degeneration. Vision Res 111:142-8
Lorach, Henri; Goetz, Georges; Smith, Richard et al. (2015) Photovoltaic restoration of sight with high visual acuity. Nat Med 21:476-82
Goetz, Georges; Smith, Richard; Lei, Xin et al. (2015) Contrast Sensitivity With a Subretinal Prosthesis and Implications for Efficient Delivery of Visual Information. Invest Ophthalmol Vis Sci 56:7186-94
Adekunle, Adewumi N; Adkins, Alice; Wang, Wei et al. (2015) Integration of Perforated Subretinal Prostheses With Retinal Tissue. Transl Vis Sci Technol 4:5

Showing the most recent 10 out of 26 publications