Eye Movement Compensation and Spatial Updating in Visual Prosthetics: Mechanisms, Limitations and Future Directions

Paraskevoudi, Nadia; Pezaris, John S.

doi:10.3389/fnsys.2018.00073

Cited by 28 publications

(26 citation statements)

References 172 publications

(392 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because the mutated capsid AAV2.7m8 has shown a stronger transduction of the peri-fovea 25 , we decided to compare its efficacy in expressing ChrimsonR (ChR) with that of the wild type AAV2 version. Then, as ChR is often used fused to the fluorescent protein tdTomato to visualize its cellular expression, we also assessed whether the native protein ChR and the fused 6 protein Chrimson-tdTomato were equally expressed in primate RGCs. The four selected constructs (AAV2 and AAV2.7m8 vectors encoding either ChR or ChR-tdT) were each injected in 4 different eyes at the same concentration (5x10 11 vg/eye) in 8 animals (Table S1).…”

Section: Subhead 1: Aav27m8-chr-dtt Provides the Greatest Efficacy Omentioning

confidence: 99%

See 1 more Smart Citation

Optogenetic therapy: High spatiotemporal resolution and pattern recognition compatible with vision restoration in non-human primates

Gauvain

Akolkar

Chaffiol

et al. 2020

Preprint

View full text Add to dashboard Cite

We select here the vector and genetic construct best suited to provide vision restoration in patients suffering from retinopathies, we demonstrate temporal resolution compatible with high dynamic visual scenes and a visual acuity above legal blindness. Abstract:.Restoring vision using optogenetics is an ideal medical application because the eye offers a direct window to access and stimulate the pathological area: the retina. Optogenetic therapy could be applied to diseases with photoreceptor degeneration such as retinitis pigmentosa. Here, we select the specific optogenetic construct that is now used in the clinical trial and assess the opsin functional efficacy on non-human primate's retinal ganglion cells (RGCs).We chose the microbial opsin ChrimsonR and showed that the vector AAV2.7m8 produced greater transfection in RGCs compared to AAV2, and that ChrimsonR attached to tdTomato (ChR-tdT) is more efficiently expressed than ChrimsonR. The 600 nm light activates the RGCs transfected with the vector AAV2.7m8-ChR-tdT from an irradiance of 10 15 photons.cm -2 .s -1 .Vector doses of 5.10 10 and 5.10 11 vg/eye transfect up to 7000 RGCs/mm 2 in the perifovea, with no significant immune reaction. Furthermore, using a multielectrode array we recorded RGCs responses starting from 1ms stimulus duration. Using the recorded activity we were able to decode stimulus information and estimate a theoretical visual acuity of 20/249, above legal blindness. Altogether, our results pave the way for the ongoing clinical trial with the AAV2.7m8-ChrimsonR-tdT vector for vision restoration in patients affected by retinitis pigmentosa.

show abstract

Section: Subhead 1: Aav27m8-chr-dtt Provides the Greatest Efficacy Omentioning

confidence: 99%

“…Since these diseases mainly affect photoreceptors, the remaining retinal layers are still available to communicate with the brain through the optic nerve. Retinal prostheses have already proven the feasibility of reactivating these retinal layers 4,5 despite their major limitations in surgery, spatial resolution and cell specificity 6 .…”

Section: Introductionmentioning

confidence: 99%

Optogenetic therapy: High spatiotemporal resolution and pattern recognition compatible with vision restoration in non-human primates

Gauvain

Akolkar

Chaffiol

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…Its proximity to the retina allows for a low stimulation threshold which in turn allows for a smaller size, while contact with the vitreous cavity fluids helps dissipate heat from the device [35, 44]. While having a processing unit between the camera and the simulating array can allow for substantial image analysis and manipulation, such systems typically require head movement from the user to steer the camera, not the more natural eye-and-head combination [31, 34, 45]. The conventional use of a tack to anchor the electrode array may also be considered a disadvantage, as it possibly causes retinal damage and long-term mechanical stability issues [34].…”

Section: Visual Prosthesesmentioning

confidence: 99%

Contemporary approaches to visual prostheses

Mirochnik

Pezaris

2019

Military Med Res

Self Cite

View full text Add to dashboard Cite

Visual prostheses serve to restore visual function following acquired blindness. Acquired blindness (as opposed to congenital blindness) has many causes, including diseases such as retinitis pigmentosa, glaucoma, and macular degeneration, or trauma such as caused by automobile accident or blast damage from explosions. Many of the blindness-causing diseases target the retina or other ocular structure. Often, despite the loss of sensitivity to light, the remainder of the visual pathway is still functional, enabling electrical devices to deliver effective and meaningful visual information to the brain via arrays of electrodes. These arrays can be placed in any part of the early visual pathway, such as the retina, optic nerve, lateral geniculate nucleus, or visual cortex. A camera or other imaging source is used to drive electrical stimulation of remaining healthy cells or structures to create artificial vision and provide restoration of function. In this review, each approach to visual prostheses is described, including advantages and disadvantages as well as assessments of the current state of the art. Most of the work to-date has been targeting stimulation of (a) the retina, with three devices approved for general use and two more in clinical testing; (b) the lateral geniculate nucleus, with efforts still in the pre-clinical stage; and (c) the cortex, with three devices in clinical testing and none currently approved for general use despite the longest history of investigation of the three major approaches. Each class of device has different medical indications, and different levels of invasiveness required for implantation. All contemporary devices deliver relatively poor vision. There has been remarkable progress since the first proof-of-concept demonstration that used stimulation of the primary visual cortex, with the field exploring all viable options for restoration of function. Much of the progress has been recent, driven by advances in microelectronics and biocompatibility. With three devices currently approved for general use in various parts of the world, and a handful of additional devices well along in the pipeline toward approval, prospects for wide deployment of a device-based therapy to treat acquired blindness are good.

show abstract

“…Eye movements, including microsaccades, are critical to designing visual prosthetics that faithfully reproduce natural vision (Macknik et al, 2019;Paraskevoudi & Pezaris, 2019;. The intended recipients of visual prostheses are typically expected to have similar numbers of (micro)saccades as normally-sighted persons (Hafed, Stingl, Bartz-Schmidt, Gekeler, & Zrenner, 2016;Shepherd, Shivdasani, Nayagam, Williams, & Blamey, 2013).…”

Section: Visual Prostheticsmentioning

confidence: 99%

Microsaccades in applied environments: Real-world applications of fixational eye movement measurements

Alexander

Macknik

Martínez-Conde

2020

JEMR

View full text Add to dashboard Cite

Across a wide variety of research environments, the recording of microsaccades and other fixational eye movements has provided insight and solutions into practical problems. Here we review the literature on fixational eye movements—especially microsaccades—in applied and ecologically-valid scenarios. Recent technical advances allow noninvasive fixational eye movement recordings in real-world contexts, while observers perform a variety of tasks. Thus, fixational eye movement measures have been obtained in a host of real-world scenarios, such as in connection with driver fatigue, vestibular sensory deprivation in astronauts, and elite athletic training, among others. Here we present the state of the art in the practical applications of fixational eye movement research, examine its potential future uses, and discuss the benefits of including microsaccade measures in existing eye movement detection technologies. Current evidence supports the inclusion of fixational eye movement measures in real-world contexts, as part of the development of new or improved oculomotor assessment tools. The real-world applications of fixational eye movement measurements will only grow larger and wider as affordable high-speed and high-spatial resolution eye trackers become increasingly prevalent.

show abstract

Eye Movement Compensation and Spatial Updating in Visual Prosthetics: Mechanisms, Limitations and Future Directions

Cited by 28 publications

References 172 publications

Optogenetic therapy: High spatiotemporal resolution and pattern recognition compatible with vision restoration in non-human primates

Optogenetic therapy: High spatiotemporal resolution and pattern recognition compatible with vision restoration in non-human primates

Contemporary approaches to visual prostheses

Microsaccades in applied environments: Real-world applications of fixational eye movement measurements

Contact Info

Product

Resources

About