Virtual reality simulation of epi-retinal prosthetic vision highlights the relevance of the visual angle

AbstractObjectiveRetinal prostheses hold the potential to restore artificial vision in blind patients suffering from outer retinal dystrophies. The optimal number, density, and coverage of the electrodes that a retinal prosthesis should have to provide adequate artificial vision in daily activities is still an open question and an important design parameter needed to develop better implants.ApproachTo address this question, we investigated the interaction between the visual angle, the pixel number and the pixel density without being limited by a small electrode count, as in previous research reports. We implemented prosthetic vision in a virtual reality environment in order to simulate the real-life experience of using a retinal prosthesis. We designed four different tasks simulating: object recognition, word reading, perception of a descending step and crossing a street.Main resultsThe results of our study showed that in all the tasks the visual angle played the most significant role in improving the performance of the participant.SignificanceThe design of new retinal prostheses should take into account the relevance of the restored visual angle to provide a helpful and valuable visual aid to profoundly or totally blind patients.

Download Full-text

Retinal Prosthetic Approaches to Enhance Visual Perception for Blind Patients

Micromachines ◽

10.3390/mi11050535 ◽

2020 ◽

Vol 11 (5) ◽

pp. 535 ◽

Cited By ~ 2

Author(s):

Shinyong Shim ◽

Kyungsik Eom ◽

Joonsoo Jeong ◽

Sung Kim

Keyword(s):

Visual Acuity ◽

Implantable Devices ◽

Artificial Vision ◽

Retinal Neurons ◽

Electrode Arrays ◽

Retinal Prostheses ◽

Future Directions ◽

Retinal Stimulation ◽

Made In ◽

Blind Patients

Retinal prostheses are implantable devices that aim to restore the vision of blind patients suffering from retinal degeneration, mainly by artificially stimulating the remaining retinal neurons. Some retinal prostheses have successfully reached the stage of clinical trials; however, these devices can only restore vision partially and remain insufficient to enable patients to conduct everyday life independently. The visual acuity of the artificial vision is limited by various factors from both engineering and physiological perspectives. To overcome those issues and further enhance the visual resolution of retinal prostheses, a variety of retinal prosthetic approaches have been proposed, based on optimization of the geometries of electrode arrays and stimulation pulse parameters. Other retinal stimulation modalities such as optics, ultrasound, and magnetics have also been utilized to address the limitations in conventional electrical stimulation. Although none of these approaches have been clinically proven to fully restore the function of a degenerated retina, the extensive efforts made in this field have demonstrated a series of encouraging findings for the next generation of retinal prostheses, and these could potentially enhance the visual acuity of retinal prostheses. In this article, a comprehensive and up-to-date overview of retinal prosthetic strategies is provided, with a specific focus on a quantitative assessment of visual acuity results from various retinal stimulation technologies. The aim is to highlight future directions toward high-resolution retinal prostheses.

Download Full-text

Optical Coherence Tomography Imaging in the Management of the Argus II Retinal Prosthesis System

European Journal of Ophthalmology ◽

10.5301/ejo.5000852 ◽

2017 ◽

Vol 27 (1) ◽

pp. 16-21 ◽

Cited By ~ 14

Author(s):

Francesco Parmeggiani ◽

Katia De Nadai ◽

Angela Piovan ◽

Andrea Binotto ◽

Sara Zamengo ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Retinitis Pigmentosa ◽

Real Life ◽

Case Series ◽

Retinal Prosthesis ◽

Implant Design ◽

Pathologic Myopia ◽

Optical Coherence ◽

Argus Ii ◽

Blind Patients

Purpose To report a real-life experience with the Argus II retinal prosthesis system in blind patients with end-stage retinitis pigmentosa (RP) or choroideremia (CHM), focusing on the pivotal role of optical coherence tomography (OCT) in both preoperative and postoperative management. Methods This hospital-based case series included 3 blind patients who were uneventfully implanted with Argus II epiretinal device. These patients (2 with RP and 1 with CHM) were selected during the Argus™ II Retinal Prosthesis System PostMarket Surveillance Study Protocol. Complete screening procedures had involved 66 eyes of 33 patients afferent to the Center for Retinitis Pigmentosa of the Veneto Region. Results Preoperative OCT examination resulted in the exclusion of 8 eyes in 4 patients with bilateral posterior staphyloma diagnosing unexpected staphylomatous macular patterns in 2 patients with RP and no sign of pathologic myopia. Postoperative OCT study of Argus II proximity to retinal surface indicated a plausible correlation between electrode–retina distance and perceptual threshold in 2 of our 3 patients. In particular, during the first 6 months of follow-up, the patient with the closest contact between device and macula showed a continuous vision-related improvement in the performance of several real-life tasks. Conclusions The present findings illustrate the modalities by which each different OCT examination is an essential tool to optimize safety and efficacy profiles during Argus II protocol. Optical coherence tomography will be crucial for future investigative approaches on patient selection criteria and next-generation implant design.

Download Full-text

Comparing Virtual Reality Tourism to Real-Life Experience: Effects of Presence and Engagement on Attitude and Enjoyment

Communication Research Reports ◽

10.1080/08824096.2018.1525350 ◽

2018 ◽

Vol 35 (5) ◽

pp. 456-464 ◽

Cited By ~ 11

Author(s):

Adam Wagler ◽

Michael D. Hanus

Keyword(s):

Virtual Reality ◽

Life Experience ◽

Real Life ◽

Experience Effects

Download Full-text

An Analysis of Learners’ Intentions Toward Virtual Reality Learning Based on Constructivist and Technology Acceptance Approaches

The International Review of Research in Open and Distributed Learning ◽

10.19173/irrodl.v19i1.2503 ◽

2018 ◽

Vol 19 (1) ◽

Cited By ~ 13

Author(s):

Hsiu-Mei Huang ◽

Shu-Sheng Liaw

Keyword(s):

Virtual Reality ◽

Technology Acceptance ◽

Life Experience ◽

Real Life ◽

Ease Of Use ◽

Perceived Usefulness ◽

Learning Motivation ◽

Perceived Ease Of Use ◽

Factors Affecting ◽

Wide Range

Within a constructivist paradigm, the virtual reality technology focuses on the learner's actively interactive learning processes and attempts to reduce the gap between the learner’s knowledge and a real-life experience. Recently, virtual reality technologies have been developed for a wide range of applications in education, but further research is needed to establish appropriate and effective learning techniques and practices to motivate meaningful learning. Results showed that perceived self-efficacy and perceived interaction are two crucial factors affecting perceived ease of use, perceived usefulness and learning motivation. Furthermore, learning motivation is also a predictor to affect perceived usefulness. After that, perceived ease of use, perceived usefulness, and learning motivation are three important factors affecting learner intention to use the virtual reality learning environment.

Download Full-text

Auditory-Visual Interactions in the Blind with Artificial Vision: Are Multisensory Perceptions Restored After Decades of Blindness?

10.1101/519850 ◽

2019 ◽

Author(s):

Noelle R. B. Stiles ◽

Vivek R. Patel ◽

James D. Weiland

Keyword(s):

Visual Perception ◽

Visual Processing ◽

Visual Motion ◽

Interaction Strength ◽

Retinal Prosthesis ◽

Artificial Vision ◽

Retinal Prostheses ◽

Natural Vision ◽

Visual Interactions ◽

The Senses

AbstractIn the sighted, auditory and visual perception typically interact strongly and influence each other significantly. Blindness acquired in adulthood alters these multisensory pathways. During blindness, it has been shown that the senses functionally reorganize, enabling visual cortex to be recruited for auditory processing. It is yet unknown whether this reorganization is permanent, or whether auditory-visual interactions can be re-established in cases of partial visual recovery.Retinal prostheses restore visual perception to the late blind and provide an opportunity to determine if these auditory-visual connections and interactions are still viable after years of plasticity and neglect. We tested Argus II retinal prosthesis patients (N = 7) for an auditory-visual illusion, the ventriloquist effect, in which the perceived location of an auditory stimulus is modified by the presence of a visual stimulus. Prosthetically-restored visual perception significantly modified patients’ auditory perceptions, comparable to results with sighted control participants (N = 10). Furthermore, the auditory-visual interaction strength in retinal prosthesis patients exhibited a significant partial anti-correlation with patient age, as well as a significant partial correlation with duration of prosthesis use.These results indicate that auditory-visual interactions can be restored after decades of blindness, and that auditory-visual processing pathways and regions can be re-engaged. Furthermore, they indicate the resilience of multimodal interactions to plasticity during blindness, and that this plasticity can either be partially reversed or at least does not prevent auditory-visual interactions. Finally, this study provides hope for the restoration of sensory perception, complete with multisensory integration, even after years of visual deprivation.SignificanceRetinal prostheses restore visual perception to the blind by means of an implanted retinal stimulator wirelessly connected to a camera mounted on glasses. Individuals with prosthetic vision can locate and identify simple objects, and identify the direction of visual motion. A key question is whether this prosthetic vision will interact with the other senses, such as audition, in the same way that natural vision does. We found that artificial vision, like natural vision, can alter auditory localization. This suggests that the brain processes prosthetic vision similarly to natural vision despite altered visual processing in the retina. In addition, it implies that reorganization of the senses during blindness may be reversible, allowing for the rehabilitation of crossmodal interactions after visual restoration.

Download Full-text

Visualising and experiencing geological flows in Virtual Reality

10.5194/egusphere-egu21-8801 ◽

2021 ◽

Author(s):

Emmanuel Delage ◽

Benjamin Van Wyk de Vries ◽

Meven Philippe ◽

Susan Conway ◽

Costanza Morino ◽

...

Keyword(s):

Virtual Reality ◽

Life Experience ◽

Real Life ◽

Digital Terrain Model ◽

Flow Simulation ◽

Point Of View ◽

Pyroclastic Flows ◽

Permafrost Degradation ◽

Communication Tool ◽

Debris Slide

Resilience to natural hazards depends on a person's ability to envision an event and its consequences. While real life experience is precious, a real event experience is rare, and sometimes fatal. So, virtual reality provides a way to getting that experience more frequently and without the inconvenience of demise. Virtual reality can also enhance an event to make it more visible, as often things happen in bad weather, at night or in other inconvenient moments.The 3DTeLC software (an output from an ERASMUS+ project, http://3dtelc.lmv.uca.fr/) can handle high-resolution 3D topographic models and the user can study natural hazard phenomena with geological tools in virtual reality. Topography acquired from drone or plane acquisitions, can be made more accessible to researchers, public and stakeholders. In the virtual environment a person can interact with the scene from the first person, drone or plane point of view and can do geological interpretation at different visualization scales. Immersive and interactive visualization is an efficient communication tool (e.g. Tibaldi et al 2019 &#8211; Bulletin of Volcanology DOI: https://dx.doi.org/10.1007/s00445-020-01376-6).We have taken the 3DTeLC workflow and integrated a 2.5D flow simulation programme (VOLCFLOW-C). The dynamic outputs from VOLCFLOW-C are superimposed into a single visualization using a new tool developed from scratch, which we call VRVOLC. This coupled visualization adds dynamic and realistic understanding of events like lahars, lava flows, landslides and pyroclastic flows. We present two examples of this, one developed on the Digital Terrain Model of Chachani Volcano, Arequipa Peru, to assist with flood and lahar visualisation (in conjunction with INGEMMET, UNESCO IGCP project 692 Geoheritage for Resilience and Cap 20-25 Clermont Risk). And another with an Icelandic debris slide that occurred in late 2014 possibly related to permafrost degradation (in conjunction with the ANR PERMOLARDS project).We thank out 3DTeCL colleagues, without which this would not be possible, and acknowledge financial support for the PERMOLARDS project from French National Research Agency (ANR-19-CE01-0010), and this is part of UNESCO IGCP 692 Geoheritage for Resilience.

Download Full-text