Retinal Prosthesis Research Articles

Restored vision-augmented vision: arguments for a cybernetic vision.

In this paper, we present some thoughts about the recent developments, made possible by technological advances and miniaturisation of connected visual prostheses, linked to the visual system, operating at different level of this one, on the retina as well as in the visual cortex. While these objects represent a great hope for people with impaired vision to recover partial vision, we show how this technology could also act on the functional vision of well sighted persons to improve or increase their visual performance. In addition to the impact on our cognitive and attentional mechanisms, such an operation when it originates outside the natural real visual field (e.g. cybernetics) raises a number of questions about the development and use of such implants or prostheses in the future.

Effective oral function improvement by restoration-driven implant treatment after mandibular resection with a scapular flap: a case report

BackgroundThe extensive loss of teeth and surrounding tissues due to mandibulectomy for an oral tumor not only impacts negatively on appearance, but also often causes various functional disorders, decreasing quality of life (QOL). In the present case, reconstruction with a scapular flap was carried out along with segmental mandibulectomy, aiming for functional restoration through restoration-driven implant treatment. A good outcome was obtained, with improvement of masticatory function and QOL following the prosthetic treatment.Case presentationThe patient was a 37-year-old woman diagnosed with ossifying fibroma in the left side of the mandible. Segmental mandibulectomy and reconstruction with a scapular flap were carried out. Implant diagnostic simulation was performed, and based on the result, secondary reconstruction using a particulate cancellous bone and marrow graft was carried out by an oral surgeon. After wound healing was complete, implant placement was performed twice, and the final prosthodontic treatment was completed. Masticatory performance and maximum bite force, which are indices of masticatory function, were improved from before to after prosthetic treatment. In addition, oral health-related QOL was improved from before to after prosthetic treatment.ConclusionIn the present case, restoration-driven implant treatment was performed in a patient following segmental mandibulectomy for a mandibular tumor, with a good outcome. Planning the treatment measures with a focus on the final prosthetic vision can lead to improvement of oral function in patients with extensive mandibular defects.

Neurostimulators for high-resolution artificial retina: ASIC design challenges and solutions

Objective. Neurostimulator is one of the most important part in artificial retina design. In this paper, we discuss the main challenges in the design of application-specific integrated circuit for high-resolution artificial retina and suggest corresponding solutions. Approach. Problems in the design of the neurostimulator for the existing artificial retina have not been solved yet are analyzed and solutions are presented. For verification of the solutions, mathematical proof, MATLAB and Ansys simulations are used. Main results. The drawbacks of resorting to a high-voltage complementary metal oxide semiconductor (CMOS) process to deal with the large voltage compliance demanded by the stimulator output stage are pointed out, and an alternative approach based on a circuit that switches the voltage of the common reference electrode is proposed to overcome. The necessity of an active discharge circuit to remove the residual charge of electrodes caused by an unbalanced stimulus is investigated. We present a circuit analysis showing that the use of a passive discharge circuit is sufficient to suppress problematic direct current in most situations. Finally, possible restrictions on input and output (I/O) count are investigated by estimating the resistive-capacitive delay caused by the interconnection between the I/O pad and the microelectrode array. Significance. The results of this paper clarified the problems currently faced by neurostimulator design for the artificial retina. Through the solutions presented in this study, circuits with more competitiveness in power and area consumption can be designed.

I‐VISION project. A new step in artificial vision

AbstractThe i‐VISION project aims to develop next‐generation of retinal prosthesis technology in efforts to restore high‐acuity artificial vision to individuals blinded by retinal degeneration. Retinal prostheses operate by electrically stimulating retinal neurons that survive the degeneration in a spatiotemporal pattern that is interpreted by the brain as vision. Presently, the challenge to implement thousands of small‐diameter electrodes and increasingly more sophisticated stimulation protocols that can adapt to the patients' needs has not been met, which severely limits the quality of restored vision in current retinal prostheses.In this presentation I will present how i‐VISION is set to address some of the challenges hindering the performance of current retinal prostheses, with a focus on the use of revolutionary miniaturized electrode nanotechnology based on graphene. Graphene microelectrodes are capable of mediating high‐charge injection highly localized that will improve the spatial resolution at the neural interface, and locally monitoring the stimulation efficacy, allowing a future adaptive therapy strategy. In addition, I will present work of the i‐VISION consortium on the use of advanced in vitro and in vivo imaging techniques of the evoked retinal and cortical responses to quantify the area of neurons activated by the electrical stimulation, with the ultimate goal of generating maps of retina‐visual cortex interconnectivity.

Restoring vision in blind patients: From optogenetic to sonogenetic therapies

AbstractVisual restoration is certainly the greatest challenge for brain‐machine interfaces with the high pixel number and high refreshing rate. In the recent year, we brought retinal prostheses and optogenetic therapy up to successful clinical trials. Optogenetics relies on the expression of a microbial opsin in residual neurons by gene therapy. These strategies can provide some vision in blind patients with diseases of photoreceptors such as retinal dystrophies or age‐related macular degeneration. They can reintroduce some information in at the retinal level by activating residual neurons after the loss of photoreceptors. For patients with optic nerve atrophy as in glaucoma and diabetic retinopathy, visual restoration requires the direct activation of the visual cortex. However, cortical prostheses have shown efficacy for limited periods of time and limited pixel numbers.In the present project, we are investigating a novel approach to restore vision at the cortical level with sonogenetic therapy. This approach relies on expressing an ultrasound‐sensitive ionic channel in cortical neurons to imprint images at this level by ultrasound stimulations.The Mscl ionic channel fused to the tdTomato reporter gene was expressed in the visual cortex of rats following a cortical AAV injection. The channel expression was indicated by the red fluorescence of tdTomato. Recording with penetrating electrodes indicated responses to cortical ultrasound stimulation with a high temporal resolution but a shorter latency than natural visual responses. In the absence of AAV injection, the visual cortex was not responsive to ultrasounds. Moving the ultrasound stimulator moved the activated area as indicated by Ecog electrode array recording. Finally, mice having learned to associate a flash of light to a water delivery responded similarly to an ultrasound cortical stimulation if the MscL protein was expressed in their cortex.These results indicate that the MscL channel induces an ultrasound sensitivity of cortical neurons generating a cortical activations with a spatiotemporal resolution suitable for vision restoration and perceived as phosphenes. Further studies will have to demonstrate true vision of forms by this sonogenetic approach prior to a clinical translation.

Towards a Smart Bionic Eye: AI-powered artificial vision for the treatment of incurable blindness

Objective. How can we return a functional form of sight to people who are living with incurable blindness? Despite recent advances in the development of visual neuroprostheses, the quality of current prosthetic vision is still rudimentary and does not differ much across different device technologies. Approach. Rather than aiming to represent the visual scene as naturally as possible, a Smart Bionic Eye could provide visual augmentations through the means of artificial intelligence-based scene understanding, tailored to specific real-world tasks that are known to affect the quality of life of people who are blind, such as face recognition, outdoor navigation, and self-care. Main results. Complementary to existing research aiming to restore natural vision, we propose a patient-centered approach to incorporate deep learning-based visual augmentations into the next generation of devices. Significance. The ability of a visual prosthesis to support everyday tasks might make the difference between abandoned technology and a widely adopted next-generation neuroprosthetic device.

Simulating the impact of photoreceptor loss and inner retinal network changes on electrical activity of the retina

Objective. A major reason for poor visual outcomes provided by existing retinal prostheses is the limited knowledge of the impact of photoreceptor loss on retinal remodelling and its subsequent impact on neural responses to electrical stimulation. Computational network models of the neural retina assist in the understanding of normal retinal function but can be also useful for investigating diseased retinal responses to electrical stimulation. Approach. We developed and validated a biophysically detailed discrete neuronal network model of the retina in the software package NEURON. The model includes rod and cone photoreceptors, ON and OFF bipolar cell pathways, amacrine and horizontal cells and finally, ON and OFF retinal ganglion cells with detailed network connectivity and neural intrinsic properties. By accurately controlling the network parameters, we simulated the impact of varying levels of degeneration on retinal electrical function. Main results. Our model was able to reproduce characteristic monophasic and biphasic oscillatory patterns seen in ON and OFF neurons during retinal degeneration (RD). Oscillatory activity occurred at 3 Hz with partial photoreceptor loss and at 6 Hz when all photoreceptor input to the retina was removed. Oscillations were found to gradually weaken, then disappear when synapses and gap junctions were destroyed in the inner retina. Without requiring any changes to intrinsic cellular properties of individual inner retinal neurons, our results suggest that changes in connectivity alone were sufficient to give rise to neural oscillations during photoreceptor degeneration, and significant network connectivity destruction in the inner retina terminated the oscillations. Significance. Our results provide a platform for further understanding physiological retinal changes with progressive photoreceptor and inner RD. Furthermore, our model can be used to guide future stimulation strategies for retinal prostheses to benefit patients at different stages of disease progression, particularly in the early and mid-stages of RD.

Self-Powered Bidirectional Photoresponse in High-Detectivity WSe2 Phototransistor with Asymmetrical van der Waals Stacking for Retinal Neurons Emulation.

An artificial retina system shows a promising potential to achieve fast response, low power consumption, and high integration density for vision sensing systems. Optoelectronic sensors, which can emulate the neurobiological functionalities of retinal neurons, are crucial in the artificial retina systems. Here, we propose a WSe2 phototransistor with asymmetrical van der Waals (vdWs) stacking that can be used as an optoelectronic sensor in artificial retina systems. Through the utilization of the gate-tunable self-powered bidirectional photoresponse of this phototransistor, the neurobiological functionalities of both bipolar cells and cone cells, as well as the hierarchical connectivity between these two types of retinal neurons, are successfully mimicked by a single device. This self-powered bidirectional photoresponse is attributed to the asymmetrical vdWs stacking structure, which enables the transition from an n-p to p+-p homojunction in the WSe2 channel under different polarities of gate bias. Moreover, the detectivity and ON/OFF ratio of this phototransistor reach as high as 1.8 × 1013 Jones and 5.3 × 104, respectively, and a rise/fall time <80 μs is achieved, as well, which reveals good photodetection performance. The proof of this device provides a pathway for the future development of neuromorphic vision devices and systems.

Instrumental Activities of Daily Living Tools in Very-Low Vision: Ready for Use in Trials?

Traditional endpoints assessing visual function are limited by their responsiveness to interventions restoring or maintaining vision. An alternative concept is assessing instrumental activities of daily living (IADL). Herein, we review all available vision-specific IADL instruments relevant for vision restoration trials and report data for the most promising instrument. Six relevant instruments exist: The Low Vision Functional Status Evaluation (LVFSE), Timed IADL (TIADL), Melbourne Low-Vision Activities of Daily Living Index (MLVAI), Assessment of Disability Related to Vision (ADREV), Functional Low-Vision Observer Rated Assessment (FLORA), and Very Low Vision IADL (IADL-VLV). Both internal consistency and test-retest data were available for the LVFSE, MLVAI, and IADL-VLV. In a sample from a low-vision clinic (n = 51; age 57 ± 16 years), we report additional validation data on the IVI-VLV including test-retest reliability (intraclass correlation coefficient 0.981 [0.961; 0.991]). The LVSFE was noticeably less reliable than the MLVAI and the IADL-VLV. Content and construct validity data were available for the LVFSE, TIADL, MLVAI, ADREV, and IADL-VLV, but only the MLVAI and IADL-VLV were developed for an ultra-low vision context. Ceiling effects were present across instruments. Thus, of all appropriate IADL instruments related to vision, the IADL-VLV and MLVAI best meet existing requirements for use in vision restoration trials, e.g., in gene therapies or visual prostheses in inherited retinal diseases, but require further validation.

Electronic photoreceptors enable prosthetic visual acuity matching the natural resolution in rats

Localized stimulation of the inner retinal neurons for high-acuity prosthetic vision requires small pixels and minimal crosstalk from the neighboring electrodes. Local return electrodes within each pixel limit the crosstalk, but they over-constrain the electric field, thus precluding the efficient stimulation with subretinal pixels smaller than 55 μm. Here we demonstrate a high-resolution prosthetic vision based on a novel design of a photovoltaic array, where field confinement is achieved dynamically, leveraging the adjustable conductivity of the diodes under forward bias to turn the designated pixels into transient returns. We validated the computational modeling of the field confinement in such an optically-controlled circuit by in-vitro and in-vivo measurements. Most importantly, using this strategy, we demonstrated that the grating acuity with 40 μm pixels matches the pixel pitch, while with 20 μm pixels, it reaches the 28 μm limit of the natural visual resolution in rats. This method enables customized field shaping based on individual retinal thickness and distance from the implant, paving the way to higher acuity of prosthetic vision in atrophic macular degeneration.

Development of neural‐network‐based stereo bionic compound eyes with fiber bundles

SummaryThe compound eye system has many unique advantages, enabling organisms to quickly and accurately obtain the three‐dimensional spatial information of the target. Therefore, its bionic applications have great potential in object localization, dynamic tracking, and 3D reconstruction. However, the current bionic compound eye systems still have great difficulties in target detection. Most of the bionic compound eye systems only verify the possibility of three‐dimensional (3D) detection, and there is no suitable calibration and detection scheme. In this article, a fiber‐optic stereo bionic compound eye is designed, and a simple and rapid calibration method suitable for this system is selected by comparing two effective optical information. Further, the system quantitatively analyzes the detection performance of the target to achieve precise positioning and dynamic trajectory tracking. In the static detection experiment, the average detection errors of the 3D position at the horizontal angle, the elevation angle and the depth are 0.33°, 0.32° and 1.84 mm, respectively. In the dynamic trajectory tracking experiment, the circle radius errors in the X‐Z plane and Y‐Z plane are 0.04 and 2.20 mm, respectively. The proposed system provides a new perspective to understand the nature of the compound eye.

Fabrication and Performance of Lobster Eye X-Ray Micro Pore Optics with the Ultra-high Aspect Ratio

Since the idea of bionic Lobster eye micropore optics was put forward, the possibility of focusing hard X-rays by this new lightweight X-ray optics has been proposed. Limited by the technological conditions of the aspect ratio (≥500), low surface roughness (≤1 nm) and the difficulty of applying metal coatings inside such narrow square channels, the high quality of these new optics have not been realized. This work demonstrates the test results for an Ultra-high aspect ratio (500:1) of iridium-coated with microchannel plate technology and atomic layer deposition technology. The sidewalls of the square channel are smoothed with a special acid-base treatment and the Root-Mean-Square of the inner wall was 0.52 ± 0.1 nm in 3 μm × 3 μm scale roughness, such that they work well as X-ray mirrors. The thickness of the metal iridium film layer was 19 nm. At the working voltage of 2 kV, the current was 0.1 mA and the angular resolution of the slumped chip in horizontal and vertical directions was 3.′9 and 4.′2, respectively. The simulation results were in good agreement with the X-ray test results.

Electrically Small Circularly Polarized UWB Intraocular Antenna System for Retinal Prosthesis.

This paper presents the design of an electrically small circularly polarized (CP) 3 × 3 mm2 antenna system as an intraocular unit for retinal prosthesis application. The system is operating in ISM and ultra-wideband (UWB) bands to target high programmability of retina stimulation and recording, respectively. The electrical dimensions, including the ground plane, are λ0/41 × λ0/41 × λ0/191. Physical limitations of the antenna are discussed based on Hansen and Collin's limitations. The proposed wire patch antenna exhibits wideband characteristics by combining multiple modes of the patch antenna in the presence of an interface PCB circuit. By loading polyimide encapsulated patch with stubs, dominant TM010 mode is combined with the higher order modes TM020-TM070 to exhibit wide -10 dB impedance bandwidth of 2-11 GHz. Annular rings and shorting pins in the ground plane provide CP radiation at 2.45, 5.8, and 8 GHz with 3-dB axial-ratio bandwidth of 0.3, 0.16, and 1.2 GHz, and far-field left hand circularly polarized (LHCP) gain of -18.4, -7.6, and -4.7 dBic, respectively, in broadside direction. A biocompatible antenna system is designed using Ansys HFSS in the presence of a detailed multilayer canonical eye model. Additionally, it is examined in an anatomical HFSS head model. Near and far-field electric field distribution is studied along with peak 1-g average specific absorption rate (SAR) calculations. The proposed antenna is fabricated, and the performance, including coupled power from an external antenna, is measured in a custom made eye model including head phantom. A reasonable agreement is obtained between simulated and measured results. To generate an artificial vision, image perception capability could be improved with implantable UWB communication systems that feature particularly high data-rate and small size.

High‐Performance Phototransistor Based on Graphene/Organic Heterostructure for In‐Chip Visual Processing and Pulse Monitoring

AbstractMimicking the real‐time sensing and processing capabilities of human retina opens up a promising pathway for achieving vision chips with high‐efficient image processing. The development of retina‐inspired vision chip also requires hardware with high sensitivity, fast image capture, and the ability to sense under various lighting conditions. Herein, a high‐performance phototransistor based on graphene/organic heterojunction is demonstrated with a superior responsivity (2.86 × 106 A W−1), an outstanding respond speed (rise time/fall time is 20 µs/8.4 ms), and a remarkable detectivity (1.47 × 1014 Jones) at 650 nm. The phototransistor combines weak‐light detection capability (minimum detectable light intensity down to 2.8 nW cm−2) with gate‐tunable bi‐directional photoresponse capable of simultaneously sensing and processing visual images for light intensities ranging over six orders magnitude (10–107nW cm−2). Moreover, the phototransistor also exhibits an intriguing feature undiscovered in other retina‐inspired devices, namely that it can real‐time monitor the human pulse signal and heart rate by using photoplethysmography technology, and the measured heart rate error is only 0.87% compared with a commercially available sensor. This study paves the way for the development of low‐light and bio‐signal sensitive artificial retinas in the future.

Adaptive Hodgkin–Huxley Neuron for Retina‐Inspired Perception

Biomimetic machine vision systems require structures, including an artificial retina to capture and process images, and an artificial network that imitates the cortex for visual inspection and identification tasks. One of the key challenges for biomimetic perceptional machine visual systems is the self‐adaptive behavior of the retina, which is known as the ability to adjust and eventually perceive objects through a wide range of environmental light intensities. To achieve this, current systems use either complex processing algorithms or specific devices with optoelectronic properties which results in complexity and less efficiency. Herein, an artificial retina circuit is reported to imitate the adaptation process to light (photopic and scotopic adaptation) of the perceptional biovisual system. The implementation of an artificial Hodgkin–Huxley neuron circuit based on adaptive VO2 memristors has helped the artificial retina to successfully demonstrate time‐varying activation and inhibition characteristics. The adaptable perception function under different illumination conditions is faithfully achieved by the artificial HH neuron based on the self‐adaptability of the memristor. The function is consistent with the dynamic light amplitude ranges of biological vision systems. More importantly, this development shows a pervasive way to design and fabricate a universal environmentally adaptable artificial system.

Progress in Developing an Emulation of a Neuromorphic Device That Is Predicted to Enhance Existing Cortical Prosthetic Vision Technology by Engaging Desired Visual Geometries

The utility of currently available cortical prosthetic vision systems is disappointing. The essential features of a neuromorphic device that is predicted to enhance vision provided by available systems follow from a hypothesis which states that the objective and subjective aspects of cortical prosthetic vision jointly constitute patterns that emerge from specified synaptic interactions. The research reported here completes several required steps in developing an emulation of this device: (1) replication of small-scale simulations that are consistent with the hypothesis using the NEST (Écublens, Vaud, Switzerland) simulator, which can also be used for full-scale network emulation by a neuromorphic computer; (2) testing whether results consistent with the hypothesis survive increasing the scale and duration of simulations; (3) establishing a method that uses numbers of spikes produced by network neurons to report the number of phosphenes produced by cortical stimulation; and (4) simulating essential functions of a neuromorphic device which is predicted to enhance current prosthetic systems. NEST simulations replicated early results and increasing their scale and duration produced results consistent with the hypothesis. A decision function created using multinomial logistic regression correctly reported the expected number of phosphenes for three sets of 2080 spike number distributions in which half of each set arises from simulations expected to yield continuous visual forms by engaging a desired visual geometry. A process for modulating electrical stimulation amplitude based on intermittent population recordings that is predicted to produce desired visual geometries was successfully simulated. Implications of these results for future research are discussed.

Implications of Neural Plasticity in Retinal Prosthesis.

Retinal degenerative diseases such as retinitis pigmentosa cause a progressive loss of photoreceptors that eventually prevents the affected person from perceiving visual sensations. The absence of a visual input produces a neural rewiring cascade that propagates along the visual system. This remodeling occurs first within the retina. Then, subsequent neuroplastic changes take place at higher visual centers in the brain, produced by either the abnormal neural encoding of the visual inputs delivered by the diseased retina or as the result of an adaptation to visual deprivation. While retinal implants can activate the surviving retinal neurons by delivering electric current, the unselective activation patterns of the different neural populations that exist in the retinal layers differ substantially from those in physiologic vision. Therefore, artificially induced neural patterns are being delivered to a brain that has already undergone important neural reconnections. Whether or not the modulation of this neural rewiring can improve the performance for retinal prostheses remains a critical question whose answer may be the enabler of improved functional artificial vision and more personalized neurorehabilitation strategies.

A mixed integer linear programming framework for improving cortical vision prosthesis designs

Although cortical vision prosthesis design has been an active area of research since the early 70s, progress in performance remains quite limited. This paper aims to develop a rigorous mathematical framework, based on mixed integer programming, for the analysis of the cortical vision prosthesis design problem and the optimal estimation of a prosthesis setup parameters. The simulated examples illustrate the unique capabilities of the proposed strategy in testing the feasibility of the goals of a prosthesis under a set of specified design constraints. Investigation of the results of the simulated examples suggest that a number of electrodes much larger than the number of cortical locations that are to be controlled is needed to achieve an improved vision experience, approaching the quality of normal vision (to reach a 300 pixels/inch resolution a million-electrode implantation is required). Thus, future research should focus on how these electrodes can be safely implanted. Once this is possible, the proposed framework can be applied to decide their optimal locations and excitation currents.

Qualitative Study for the Design and Fabricate of Assistive Technologies for the Visually Impaired and Blind People to Improve the Quality of Life

From the distant past until now, various assistive devices and equipment have been made and marketed for the purpose of improving the life of blind people. Braille and the white cane can be noted as one of the most basic auxiliary equipment for the blind people. Over time and through the advancement of technology, a great change has taken place in the world of the blinds; and we can see everyday development of various tools which all of them are useful in improving the life of the blind people. Today, there are various helpful tools for the blind including Obstacle detection gadgets, Text reading tools, Money detection systems, Routing systems, Audio clock, Brain port, Braille tablet, Artificial eyes (bionic eyes), etc. In this article, we will have an overview of assistive devices made for the blinds. Examination of the produced medical equipment in this field will make it possible to provide more qualified assistive equipment for the blind.

(Invited) Biomimetic Eyes with Perovskite Nanowire Array Retina

Human eyes are masterpiece of nature, which can realize powerful image sensing with a very concise structure. Biomimetic eyes with characters comparable to human eyes are highly desirable in many technological applications, particularly in the fields of visual prosthesis and machine vision. The World Health Organization reported that globally there are over 252 million people suffering from visual impairment in the year of 2020. This number is exploding due to the prevalence of various mobile devices with small displays. Bionic eyes implantation is one the most effective strategy for vison restoration. However, today, even the most mature bionic eyes have only 300 clinical trials, which is merely 1 ppm of all the visual impaired patients, mainly due to their poor performance and high cost. In addition, industrial applications such as autonomous driving and humanoids also desire cameras with high performance. To achieve biomimetic eyes with imaging performance on a par with human eyes, innovative device structure design and material selection have to be carried out simultaneously. Among all the photosensing material candidates, the ordered one-dimensional (1D) semiconductor nanowire (NW) arrays exhibit unique advantages such as fast carrier transportation and strong light-material interaction due to their anisotropic structure in axial and radial direction, thereby leading to fast response and high responsivity. This presentation focuses on our work on the NW arrays image sensing and can be highlighted as:1) Controlled growth of well aligned, high-density NW arraysDespite the advantages abovementioned, the integration of NWs has always been a bottleneck challenge hurdling their practical applications. Direct growth of NW arrays can be an effective way to tackle this challenge. We reported for the first time a unique fabrication process to form large-scale, 3D, high-density arrays of lead halide perovskite NWs with well-engineered geometry through a template-assisted growth approach. The array demonstrated amazingly geometry dependent optoelectronic properties and thereby can be used to improve performance of various devices. Particularly, its high regularity leads to the possibility to electrically addressable individual NWs which makes it an ideal candidate for very-large-scale integrated (VLSI) electronics and optoelectronics. The interaction between nanotemplate and sensing materials can introduce unique device performance such as tunable photoresponse and improved stability of perovskites.2) Assembly of integrated, NW arrays based planar image sensorsTo demonstrate the technological potency of the NW arrays, we have developed new process to fabricate them into proof-of-concept image sensors. Each image sensor consists of 1,024 photodiode pixels made of vertical perovskite NWs, and the imaging functionality has been verified by recognizing various optical patterns projected onto it. The high density of this NW array and the addressability of individual NW enable this unique image sensor design a potential, extremely high resolution approaching optical diffraction limit. To realize the device assembly, we have developed a PDMS-assisted dry transfer process which can transfer the thin (µm scale) and large-area (cm scale) film onto any substrate without any bubbles and wrinkles. This unique NW manipulation strategy, together with NW geometrical and compositional tunability, may lead to new functionality and inspire novel device design in the future.3) Invention of a 3D, biomimetic eye with a hemispherical NW array retinaThe high performance of human eyes originates from the dome shape of retina and the high-density photoreceptors in it. However, the commercial image sensors are dominantly using planar device structures shaped by the mainstream planar microfabrication processes, making it hardly possible for hemispherical device fabrication. In our work, we have developed a novel artificial visual system using a spherical biomimetic electrochemical eye with hemispherical retina made of a high-density perovskite NW array. The device has high similarity to human eyes with part of its photodetection performance superior to human eyes. The hemispherical artificial retina has NW density much higher than that of photoreceptors in a human retina thus can potentially achieve a higher image resolution which is bolstered by implementation of a single-NW ultra-small photodetector. The work may lead to a new generation of photosensing devices based on a bioinspired design that can benefit a wide spectrum of technological applications.In all, with the unique structural properties of NW arrays as the starting point, we realized their controlled growth, developed strategies to manipulate them and designed proper device structures to fully fulfill their advantages. In the future, we will combine them with brains, either biological or digital brains, to explore their applications in fields such as visual prothesis and artificial intelligence. Figure 1