Retinal Prostheses: Bioengineering Considerations

Chang, Yao-Chuan; Weiland, James D.; Humayun, Mark S.

doi:10.1007/978-3-319-67260-1_2

Cited by 2 publications

(1 citation statement)

References 47 publications

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“…Iris II epiretinal implant [1]. It has been previously reported that position of the external camera causes a displacement in the egocentric spatial frame of reference in patients, leading to pointing and localisation errors [7,8]. However, there is limited understanding of how camera position affects the performance and behavioural correlates of eye-hand coordination tasks such as target localisation.…”

Section: Introductionmentioning

confidence: 99%

Effect of camera position on egocentric localisation with Simulated Prosthetic Vision

et al. 2021

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Objective: The positioning of the external camera in current designs of retinal prostheses may affect the egocentric spatial frame of reference and lead to pointing and localisation errors. The present simulated prosthetic vision (SPV) study investigated the immediate effects of four camera positions: (i) centre-mounted (CM), (ii) head-mounted (HM), (iii) left-mounted (LM), (iv) right-mounted (RM) on egocentric localisation. Approach: Fifteen sighted participants performed a pointing task while viewing the stimulus through a simulation of Bionic Vision Technologies’ 44-channel retinal prosthesis. Pointing responses were recorded immediately after exposure to different camera positions and prior to adaptation. The direction and magnitude of pointing errors and associated head movement behaviour were analysed using linear mixed effects analysis. Main results: Our results showed lower errors for medial camera positions (CM and HM) and overall improved accuracy and precision for CM position. Head orientation was found to largely influence the direction of pointing. There was a high positive correlation between direction of head orientation and direction of pointing with CM and HM camera positions, suggesting medial camera positions facilitated intuitive head orientation cues that are important for reliable egocentric direction estimation. Significance: The empirical evidence derived from the present SPV study offers practical guidance to reduce the effect on spatial dissociation of camera position in localisation tasks and inform design of future prosthetic vision devices and improve rehabilitation approaches.

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Section: Introductionmentioning

confidence: 99%

Effect of camera position on egocentric localisation with Simulated Prosthetic Vision

et al. 2021

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Platinum Nanocrystal Assisted by Low‐Content Iridium for High‐Performance Flexible Electrode: Applications on Neural Interface, Water Oxidation, and Anti‐Microbial Contamination

Zeng

Huang

Cai

et al. 2021

Adv Materials Inter

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Despite high charge capacity, iridium oxide (IrOx) coating is susceptible to delamination under prolonged stimulation, restricting its long‐term application. Here, a flower‐shaped platinum (Pt) nanocrystal with intensive high‐surface area is developed as an intermediate layer for accumulating IrOx (<3 wt% Ir) with enhanced adhesion, showing a multiplier effect. The impedance of IrOx/Pt flower coated microelectrode at 1 kHz is down to ≈2 kΩ (reduction of 94.23%). The corresponding cathodic charge storage capacity (CSCc) and charge injection capacity (CIC) are increased up to 202.75 ± 2.18 and 6.53 ± 0.16 mC cm–2, respectively. IrOx layer adheres tightly to Pt nanocrystals, demonstrating robust chronic stability under continuous electrostimulation for 1 × 108 cycles. Besides, the as‐prepared coatings show good biosafety, and exhibit promising electrocatalytic activity toward oxygen evolution reaction (OER) in 0.5 m sulfuric acid (H2SO4), requiring a low overpotential of ≈150 mV to reach 10 mA cm–2. IrOx helps in reducing the Tafel slope of Pt flower from 162.9 to 41.1 mV dec–1 drastically, also with excellent durability after chronoamperometry test. Excellent antibacterial properties toward Escherichia coli are also observed. This coating strategy provides a functionalized flexible electrode for neural interface, water oxidation, and anti‐microbial contamination, which will moreover extend to numerous applications.

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Retinal Prostheses: Bioengineering Considerations

Cited by 2 publications

References 47 publications

Effect of camera position on egocentric localisation with Simulated Prosthetic Vision

Effect of camera position on egocentric localisation with Simulated Prosthetic Vision

Platinum Nanocrystal Assisted by Low‐Content Iridium for High‐Performance Flexible Electrode: Applications on Neural Interface, Water Oxidation, and Anti‐Microbial Contamination

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