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

Abstract

2829 Introduction: Retinal implants have now been approved and commercially available for certain 30 clinical populations for over 5 years, with hundreds of individuals implanted, scores of them closely 31 followed in research trials. Despite these numbers, however, few data are available that would help 32 us answer basic questions regarding the nature and outcomes of artificial vision: what do 33 participants see when the device is turned on for the first time, and how does that change over time? 34 35 Methods: Semi-structured interviews and observations were undertaken at two sites in France and 36 the UK with 16 participants who had received either the Argus II or IRIS II devices. Data were 37 collected at various time points in the process that implant recipients went through in receiving and 38 learning to use the device, including initial evaluation, implantation, initial activation and systems 39 fitting, re-education and finally post-education. These data were supplemented with data from 40 interviews conducted with vision rehabilitation specialists at the clinical sites and clinical 41 researchers at the device manufacturers (Second Sight and Pixium Vision). Observational and 42 interview data were transcribed, coded and analyzed using an approach guided by Interpretative 43 Phenomenological Analysis (IPA). 4445 Results: Implant recipients described the perceptual experience produced by their epiretinal 46 implants as fundamentally, qualitatively different than natural vision. All used terms that invoked 47 electrical stimuli to describe the appearance of their percepts, yet the characteristics used to 48 describe the percepts varied significantly between participants. Artificial vision for these 49 participants was a highly specific, learned skill-set that combined particular bodily techniques, 50 associative learning and deductive reasoning in order to build a "lexicon of flashes" -a distinct 3 51 perceptual vocabulary that they then used to decompose, recompose and interpret their 52 surroundings. The percept did not transform over time; rather, the participant became better at 53 interpreting the signals they received. The process of using the device never ceased to be 54 cognitively fatiguing, and did not come without risk or cost to the participant. In exchange, 55 participants received hope and purpose through participation, as well as a new kind of sensory 56 signal that may not have afforded practical or functional use in daily life but, for some, provided a 57 kind of "contemplative perception" that participants tailored to individualized activities. 58 59 Conclusion: Attending to the qualitative reports of participants regarding the experience of artificial 60 vision provides valuable information not captured by extant clinical outcome measures. These data 61 can both inform device design and rehabilitative techniques, as well as grant a more holistic 62 understanding of the phenomenon of artificial vision. 63 64 Introduction 65 66 Retinal prostheses are implantable microelectronic devices de...

Naturalistic spatiotemporal stimulus modulation during epiretinal stimulation increases the persistence of retinal ganglion cell responsivity

“…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].…”

Single-pixel epiretinal stimulation with a wide-field and high-density retinal prosthesis for artificial vision

“…Patients implanted with retinal prostheses were able to localise and identify letters or objects, and perform orientation tasks [20][21][22] . Despite the effort of the research community and the enthusiasm of the patients, the majority of the latter ceased using their implant in the first to the third year following their surgery 23 . Furthermore, one-third of the users of the Argus® II epiretinal prosthesis (the most implanted so far) declared that the device had a neutral impact on their quality of life after three years 24 .…”

“…Furthermore, one-third of the users of the Argus® II epiretinal prosthesis (the most implanted so far) declared that the device had a neutral impact on their quality of life after three years 24 . This discouragement can be attributed to quantitative limitations of retinal prostheses in daily use 23 .…”

“…for the Argus® II 4 , 6 x 10 electrodes with a 525-µm pitch), in combination with the small visual angle, provides little help in daily tasks involving object identification and recognition. Last, patients reported that the use of retinal prostheses is cognitively exhausting due to the constant need of space decomposition 23 : because of the limited visual angle, the users are instructed to move their head and body to scan the environment. Scanning implies a constant visual decomposition and mental reconstruction of the visual scene, often guided by a complex pairing of the coarse visual information with audio-tactile cues 23 .…”

“…Last, patients reported that the use of retinal prostheses is cognitively exhausting due to the constant need of space decomposition 23 : because of the limited visual angle, the users are instructed to move their head and body to scan the environment. Scanning implies a constant visual decomposition and mental reconstruction of the visual scene, often guided by a complex pairing of the coarse visual information with audio-tactile cues 23 . Studies under simulated prosthetic vision identified a visual angle of 30 degrees as the minimal requirement to efficiently complete everyday mobility and manipulation tasks [27][28][29][30] .…”