What do blind people “see” with retinal prostheses? Observations and qualitative reports of epiretinal implant users

Abstract

Introduction Retinal implants have now been approved and commercially available for certain clinical populations for over 5 years, with hundreds of individuals implanted, scores of them closely followed in research trials. Despite these numbers, however, few data are available that would help us answer basic questions regarding the nature and outcomes of artificial vision: what do recipients see when the device is turned on for the first time, and how does that change over time? Methods Semi-structured interviews and observations were undertaken at two sites in France and the UK with 16 recipients who had received either the Argus II or IRIS II devices. Data were collected at various time points in the process that implant recipients went through in receiving and learning to use the device, including initial evaluation, implantation, initial activation and systems fitting, re-education and finally post-education. These data were supplemented with data from interviews conducted with vision rehabilitation specialists at the clinical sites and clinical researchers at the device manufacturers (Second Sight and Pixium Vision). Observational and interview data were transcribed, coded and analyzed using an approach guided by Interpretative Phenomenological Analysis (IPA). Results Implant recipients described the perceptual experience produced by their epiretinal implants as fundamentally, qualitatively different than natural vision. All used terms that invoked electrical stimuli to describe the appearance of their percepts, yet the characteristics used to describe the percepts varied significantly between recipients. Artificial vision for these recipients was a highly specific, learned skill-set that combined particular bodily techniques, associative learning and deductive reasoning in order to build a “lexicon of flashes”—a distinct perceptual vocabulary that they then used to decompose, recompose and interpret their surroundings. The percept did not transform over time; rather, the recipient became better at interpreting the signals they received, using cognitive techniques. The process of using the device never ceased to be cognitively fatiguing, and did not come without risk or cost to the recipient. In exchange, recipients received hope and purpose through participation, as well as a new kind of sensory signal that may not have afforded practical or functional use in daily life but, for some, provided a kind of “contemplative perception” that recipients tailored to individualized activities. Conclusion Attending to the qualitative reports of implant recipients regarding the experience of artificial vision provides valuable information not captured by extant clinical outcome measures.

Naturalistic spatiotemporal modulation of epiretinal stimulation increases the response persistence of retinal ganglion cell

“…This fate matches the abandon rate in cochlear implant or upper-limb prosthesis users that, if not abandoned, they often become an intermittent aid due to both their physiological and cognitive burden [38][39][40][41]. Similarly, artificial vision is a highly specific cognitive task, that implies long associative learning but also a permanent multisensory adjustment of the perception [37,35].…”

“…The artificial vision provided by retinal implants allows profoundly blind patients to perform visual guided tasks, such as orientation, navigation, object recognition, object manipulation and reading [33,34]. However, the unnaturalistic vision provided by the current retinal prostheses is a significant issue to implanted patients in daily life [18,35,36]. A very small fraction of users decides to keep using their prosthesis at the end of the clinical trial due to the cognitive load of its use [35,37].…”

“…However, the unnaturalistic vision provided by the current retinal prostheses is a significant issue to implanted patients in daily life [18,35,36]. A very small fraction of users decides to keep using their prosthesis at the end of the clinical trial due to the cognitive load of its use [35,37]. This fate matches the abandon rate in cochlear implant or upper-limb prosthesis users that, if not abandoned, they often become an intermittent aid due to both their physiological and cognitive burden [38][39][40][41].…”

Furthering Visual Accessibility with Extended Reality (XR): A Systematic Review

“…Most of the studies above relied on the so-called "scoreboard" method to render phosphenes, which assumes that each phosphene acts as a small independent light source, analogous to the images projected on the light bulb arrays of some sports stadium scoreboards [24]. However, a growing body of evidence suggests that the vision generated by current visual prostheses is "fundamentally different" from natural vision [26], with interactions between implant technology and the neural tissue degrading the quality of the generated artificial vision [8,29]. It is therefore unclear how the findings of most SPV studies would translate to real bionic eye users.…”

A Computational Model of Phosphene Appearance for Epiretinal Prostheses

“…However, a growing body of evidence suggests that the vision provided by these devices differs substantially from natural eyesight [7], [8], [10], [12]. Retinal implant users often report seeing distorted percepts and require extensive rehabilitative training to make use of their new vision [10]. Although single-electrode phosphenes are consistent from trial to trial, they vary across electrodes and users [7], [21].…”