Artificial Eye Research Articles

A bio-inspired polarization navigation sensor based on artificial compound eyes

Insect compound eyes are optical systems with small volume and a compact structure. The ommatidia in the dorsal rim area of some insects have polarized vision, which can perceive the polarization pattern of the sky and provide them with navigation information. In this paper, inspired by the polarization-sensitive compound eyes of insects, a bio-inspired polarization navigation sensor based on artificial compound eyes is designed. The sensor consists of an artificial compound eye, an integrated polarization detector and an integrated circuit. The optical path of the sensor uses the lens defocus method, which can ensure that the sensor obtains redundant polarization information. The integrated polarization detector is used to obtain the polarization information of the incident light, and the integrated circuit is responsible for the calculation. To extract effective information from images, we propose a multi-threshold segmentation method to filter and classify effective pixels. We use the least squares method to fit the inherent error of the sensor and then compensate it. The indoor calibration accuracy of the sensor is ±0.3°, and the outdoor calibration accuracy is ±0.5°. The sensor can provide accurate direction information for general smart mobile devices. The size of the sensor is 4 × 4 × 2 cm, and the weight is only 15 g. The key components of the sensor can be mass-produced, and it is a miniaturized and low-cost polarization navigation sensor.

P‐23: A Monolithically Integrated Artificial Compound Eye for Proximity Pattern Recognition

A biomimetic artificial compound eye is constructed as an array of pixels each consisting of in‐pixel circuits made of several metal‐oxide thin‐film transistors, a hydrogenated amorphous silicon photodiode and a structured optical path. An in‐pixel amplifier is incorporated to enhance the signal‐to‐noise ratio. The peak fabrication temperature of 300 �C is compatible with flexible substrates. Using an artificial neural network implementation, the compound eye has been trained for proximity pattern recognition at a separation of 12 mm and achieving an inference accuracy of 95%. Sensing at a larger separation is being implemented by re‐designing the optical path, leading to potential recognition of dynamic gestures.

Vitreoretinal surgical training—assessment of simulation, models, and rubrics—a narrative review

Background and Objective: Vitreoretinal surgery requires fine micro-surgical training and handling of delicate tissue. To aid in the training of residents and fellows, unique educational modalities exist to help facilitate the development of these microsurgical skills. From virtual simulators to artificial eye models, simulation of the posterior segment has gained an increased focus in vitreoretinal surgical training programs. Development of surgical curricula for vitreoretinal training and attainment of surgical milestones has been a key component in integrating these educational training modalities. We will explore various simulators, eye models, and potential rubrics and discuss unique ways each may help and complement one another to train future vitreoretinal surgeons.

An automated auroral detection system using deep learning: real-time operation in Tromsø, Norway

The activity of citizen scientists who capture images of aurora borealis using digital cameras has recently been contributing to research regarding space physics by professional scientists. Auroral images captured using digital cameras not only fascinate us, but may also provide information about the energy of precipitating auroral electrons from space; this ability makes the use of digital cameras more meaningful. To support the application of digital cameras, we have developed artificial intelligence that monitors the auroral appearance in Tromsø, Norway, instead of relying on the human eye, and implemented a web application, “Tromsø AI”, which notifies the scientists of the appearance of auroras in real-time. This “AI” has a double meaning: artificial intelligence and eyes (instead of human eyes). Utilizing the Tromsø AI, we also classified large-scale optical data to derive annual, monthly, and UT variations of the auroral occurrence rate for the first time. The derived occurrence characteristics are fairly consistent with the results obtained using the naked eye, and the evaluation using the validation data also showed a high F1 score of over 93%, indicating that the classifier has a performance comparable to that of the human eye classifying observed images.

A Case of Ocular Defect: Prosthetic Rehabilitation with Semi Customized Prosthesis

Facial defect rehabilitation is a challenging task. Individualized technique is required for each patient to accomplish the task. Due to any cause loss of an eye with disfigurement of face makes severe physical and psychological distress. A 65-year-old male Patient complaint with missing left eye was referred to the Department of Prosthodontics, Military Dental Centre Dhaka for artificial eye replacement. A defect with compressed orbit and unharmed tissue bed was found by clinical examination. Mode of rehabilitation for the missing eye is ocular prosthesis. Here I tried to describe a simple technique for the fabrication of ocular prosthesis. With stock iris and customized sclera, we have fabricated a semi customized ocular prosthesis. It provides very good result functionally and esthetically. JAFMC Bangladesh. Vol 17, No 2 (December) 2021: 95-98

A biomimetic compound eye lens for photocurrent enhancement at low temperatures

In this study, an artificial compound eye lens (ACEL) was fabricated using a laser cutting machine and polyvinyl alcohol (PVA) solution. A laser cutter was used to punch micro-sized holes (500 μm diameter—the smallest possible diameter) into an acrylic plate; this punched plate was then placed on the aqueous PVA solution, and the water was evaporated. The plate was used as the mold to obtain a polydimethylsiloxane (PDMS) micro lens array film, which was fixed to a dome-shaped three-dimensional-printed mold for further PDMS curing, and a hemispherical compound eye lens was obtained. Using a gallium nitride (GaN) photodetector, a light detection experiment was performed with the ACEL, bare lens, and no lens by irradiating light at various angles under low temperatures. The photodetector with the ACEL generated a high photocurrent under several conditions. In particular, when the light was irradiated at 0° and below −20 °C, the photocurrent of the GaN sensor with the ACEL increased by 61% and 81% compared with the photocurrent of the GaN sensor with the bare lens and without a lens, respectively. In this study, a sensor for detecting light with ACEL was demonstrated in low-temperature environments, such as indoor refrigerated storages and external conditions in Antarctica and Arctic.

Autologous platelet-rich plasma eye drop versus artificial tear eye drop for symptomatic dry eye disease: A prospective comparative interventional study.

Purpose:To evaluate and compare the efficacy of autologous platelet-rich plasma (aPRP) eye drop and artificial tear (AT) eye drop in moderate to severe symptomatic dry eye disease (DED).Methods:This prospective interventional study included 121 eyes of 61 patients of moderate to severe DED. Patients were divided into aPRP (31 patients) and AT (30 patients) group. Ocular Surface Disease Index (OSDI) score, tear film breakup time (TBUT) (s), corneal fluorescein staining (CFS) score, and Schirmer test score (mm) of both the groups were evaluated and compared pre-treatment and post-treatment at the end of 3 months.Results:The mean age of the aPRP group and AT group was 52.8 ± 12.8 years and 55.5 ± 13.4 years, respectively. At the end of 3 months, OSDI score reduced more in the aPRP group as compared to AT group, and the mean difference (−22.7) was statistically significant (P < 0.001). There was no significant difference in post-treatment Schirmer test score between the two groups (P = 0.44). Post-treatment improvement in TBUT and CFS score in the aPRP group was significantly higher in the aPRP group as compared to that in the AT group (P < 0.05). Bruising at the site of blood withdrawal was noted in two patients in the aPRP group.Conclusion:aPRP is safe and more effective than AT in treating patients with moderate to severe symptomatic DED.

Augmented Reality, Virtual Reality, and Game Technologies in Ophthalmology Training

Ophthalmology is a medical profession with a tradition in teaching that has developed throughout history. Although ophthalmologists are generally considered to only prescribe contact lenses, and they handle more than half of eye-related enhancements, diagnoses, and treatments. The training of qualified ophthalmologists is generally carried out under the traditional settings, where there is a supervisor and a student, and training is based on the use of animal eyes or artificial eye models. These models have significant disadvantages, as they are not immersive and are extremely expensive and difficult to acquire. Therefore, technologies related to Augmented Reality (AR) and Virtual Reality (VR) are rapidly and prominently positioning themselves in the medical sector, and the field of ophthalmology is growing exponentially both in terms of the training of professionals and in the assistance and recovery of patients. At the same time, it is necessary to highlight and analyze the developments that have made use of game technologies for the teaching of ophthalmology and the results that have been obtained. This systematic review aims to investigate software and hardware applications developed exclusively for educational environments related to ophthalmology and provide an analysis of other related tools. In addition, the advantages and disadvantages, limitations, and challenges involved in the use of virtual reality, augmented reality, and game technologies in this field are also presented.

Self-powered, broadband, and polarization-sensitive pyroelectric-photoelectric photodetector based on silicon-water heterojunction

The coupling of pyroelectric and photoelectric effects is a new method to enhance transient response while maintaining steady-state response in photodetectors. Such photodetectors have recently attracted a great attention due to a wide range of potential applications including artificial electronic eyes, neuromorphic computing, color sensors, and optical communications. Here, we report a photodetector based on the pyroelectricity and photoelectricity effect in a silicon-water heterojunction for the first time. Facilitated by the polarity of water on the Si surface, this heterostructure serves as a pyroelectric-based photodetector with a responsivity as high as 754 mA/W and specific detectivity as high as 1.33 × 1013 Jones under a light wavelength of 400 nm at zero bias. Also, the formation of a built-in electric field at the silicon-water interface results in a photoelectric-based photodetector with a responsivity as high as 12.3 A/W and an ultrahigh detectivity of 2.18 × 1014 Jones at −2 V bias under steady-state conditions. Moreover, due to the polarization-sensitive reflection of light on the water surface, this structure is also polarization-sensitive. These photodetectors are suitable for liquid-compatible applications that require broadband detection, high responsivity, and polarization-sensitivity.

Anthropomorphic Robotic Eyes: Structural Design and Non-Verbal Communication Effectiveness.

This paper shows the structure of a mechanical system with 9 DOFs for driving robot eyes, as well as the system’s ability to produce facial expressions. It consists of three subsystems which enable the motion of the eyeballs, eyelids, and eyebrows independently to the rest of the face. Due to its structure, the mechanical system of the eyeballs is able to reproduce all of the motions human eyes are capable of, which is an important condition for the realization of binocular function of the artificial robot eyes, as well as stereovision. From a kinematic standpoint, the mechanical systems of the eyeballs, eyelids, and eyebrows are highly capable of generating the movements of the human eye. The structure of a control system is proposed with the goal of realizing the desired motion of the output links of the mechanical systems. The success of the mechanical system is also rated on how well it enables the robot to generate non-verbal emotional content, which is why an experiment was conducted. Due to this, the face of the human-like robot MARKO was used, covered with a face mask to aid in focusing the participants on the eye region. The participants evaluated the efficiency of the robot’s non-verbal communication, with certain emotions achieving a high rate of recognition.

Understanding the Experiences of Living With an Artificial Eye in Children With Retinoblastoma-Perspectives of Children and Their Parents.

Background: Retinoblastoma is a rare form of pediatric eye cancer for which enucleation is a common treatment modality. There is an increasing focus upon the impact of enucleation on children and families. This study aimed to explore the experiences of children and their families following enucleation to consider the barriers that may be encountered when adjusting to living with an artificial eye and identifying the support services and strategies used to address these barriers. Methods: Using a descriptive qualitative approach, interviews were conducted with 12 parents and seven children and thematic analysis was used to identify four themes representing the perspective of parents and children. Results: Parent themes identified were (a) entry into the world of retinoblastoma; (b) the importance of specialist support; (c) a family learning to cope; and (d) navigating school. The perspectives of children were (a) the importance of preparation and play; (b) positive reinforcement and hospital support; (c) support and openness at home; and (d) the importance of good school planning. Two overarching themes related to parent and child adaptation were also identified. Discussion: The study findings reveal that the process of adapting to living with an artificial eye extended to influencing decisions around parenting, learning to advocate for their child, and supporting children through school and peer relationships. For children, the importance of ongoing support and information was vital to enhance understanding, adaptation, and development of independence. Overall, the study suggests that children and families undergoing enucleation need continuing, individualized, and specialist support.

Psychological aspects of living with an artificial eye

ABSTRACT Purpose Artificial eye clinics address physical and aesthetic aspects of orbital prostheses, but psychological effects may not be formally addressed. In general, without effective coping mechanisms, stress can lead to anxiety and depression. This study aims to determine, in the context of having an artificial eye, whether coping strategies, as well as perception of illness and other demographic and clinical variables are associated with anxiety or depression. Methods Consecutive patients attending two artificial eye clinics were invited to participate in this audit. Participants completed questionnaires: HADS, Brief IPQ and Brief COPE. Variables with a correlation coefficient of ≥0.2 with anxiety or depression were included in regression modeling. The extent to which the participants’ emotional and cognitive representations of their artificial eye related to feelings of anxiety and depression was determined. Results In the cohort of 208, clinically significant anxiety was present in 29.5% and clinically significant depression was present in 8.4%. Perceptions of the impact of the artificial eye and self-blame as a coping strategy were correlated with anxiety. Depression levels were higher when participants believed that their artificial eye had a greater impact on their life, when they lived alone, and when they used substances as a coping strategy. Conclusion Significant levels of anxiety exist in those living with artificial eyes, with various coping strategies used. Addressing this and offering alternative coping strategies may improve patient well being and overall satisfaction.

Additive Manufacturing of a Miniature Functional Trocar for Eye Surgery.

Stereolithography is emerging as a promising additive manufacturing technology for a range of applications in the medical domain. However, for miniature, medical devices such as those used in ophthalmic surgery, a number of production challenges arise due to the small size of the components. In this work, we investigate the challenges of creating sub-millimeter features for a miniature, functional trocar using Stereolithography. The trocar cannula system is used in eye surgery to facilitate a passage for other instruments. A standard trocar consists of a hollow cannula and a flexible check valve. The research was performed in two stages: in the first stage we investigated the effect of different materials and print settings on the current design of the cannula and the valve separately, and in the second stage we used these findings to optimize the design and production process. After the first investigation, it became apparent that even though the dimensions of the trocar are within the feature size range of Stereolithography, all hollow features tended to fuse shut during printing. This effect appeared regardless of the materials or print settings, and can be attributed to refraction of the laser source. In order to circumvent this, we identified two potential strategies: (1) increasing the negative space surrounding features; and (2) decreasing the surface area per layer. By applying these strategies, we tested a new design for the cannula and valve and managed to 3D print a functional trocar, which was tested in an artificial eye. The design of the 3D printed trocar allows for further personalization depending on the specific requirements of both patient and surgeon. The proposed strategies can be applied to different applications to create miniature features using Stereolithography.

Frontalis Sling Using a Silicone Rod for Ptosis in Third Nerve Palsy: Cosmesis versus Safety.

PurposeTo evaluate the results of the frontalis sling operation using a silicone rod for the correction of ptosis in patients with third nerve palsy with a focus on corneal safety.MethodsPatients with third nerve palsy who underwent the frontalis sling operation using a silicone rod between 2008 and 2019 were included in this study. The medical records of all patients were reviewed, and their clinical characteristics and postoperative outcomes were analyzed. In this retrospective, interventional case series, the main outcome measures were eyelid contour, eyelid height by margin reflex distance, and corneal status.ResultsTwenty-four eyes of 18 patients (12 male and six female patients) were included. The mean age at the time of surgery was 35.1 years (range, 5–64 years). Twelve patients underwent a unilateral ptosis operation, and six patients received a bilateral ptosis operation. The mean follow-up period was 32.1 months (range, 2–87 months). Most patients (21 of 24 eyes, 88%) showed poor Bell’s phenomenon on preoperative examination. Satisfactory eyelid height and eyelid contour were achieved in almost all patients (mean postoperative margin reflex distance, +1.2 mm) postoperatively. Although corneal erosions were detected for several months in eight of 24 eyes after surgery, these findings were well controlled medically with artificial tear eye drops and ointments.ConclusionsFrontalis sling surgery using a silicone rod can safely and effectively correct ptosis without severe corneal complications in patients with third nerve palsy. Our study outlines a new method to define the postoperative safety outcome by specifically focusing on categorized corneal status.

Iris Liveness Detection Using a Cascade of Dedicated Deep Learning Networks

Iris pattern recognition has significantly improved the biometric authentication field due to its high stability and uniqueness. Such physical characteristics have played an essential role in security applications and other related areas. However, presentation attacks, also known as spoofing techniques, can bypass biometric authentication systems using artefacts such as printed images, artificial eyes, textured contact lenses, etc. Many liveness detection methods that improve the robustness of these systems have been proposed. The first International Iris Liveness Detection competition, where the effectiveness of liveness detection methods is evaluated, was first launched in 2013, and its latest iteration was held in 2020. In this paper, we present the approach that won the LivDet-Iris 2020 competition using two-class scenarios (bona fide iris images vs. presentation attack iris images). Additionally, we propose new three-class and four-class scenarios that complement the competition results. These methods use a serial architecture based on a MobileNetV2 modification, trained from scratch to classify bona fide iris images versus presentation attack images. The bona fide class consists of live iris images, whereas the attack presentation instrument classes consist of cadaver, printed, and contact lenses images, for a total of four species. All the images were pre-processed and weighted per class to present a fair evaluation. This approach is primarily focused on detecting the bona fide class over improving the detection of presentation attack instruments. For the two, three, and four classes scenarios BPCER <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> values of 0.99%, 0.16%, and 0.83% were obtained respectively, whereas for the BPCER <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">20</sub> values of 3.09%, 0.16%, and 3.77% were obtained, with the best model overall being the proposed 3-class serial model. This work reaches competitive results according to the reported results in the LivDet-Iris 2020 competition.

Development of superimposing electroretinogram for identifying the retinal layer causing a decline in visual sensitivity at arbitrary points on the retina

AbstractPurposeAlthough the decline in visual sensitivity of the retina can be measured by microperimetry, it is difficult to identify the retinal layer causing this decline. We investigated cryptogenic diseases, such as macular dystrophy, by developing an electroretinogram (ERG) superimposing seven multifocal hexagonal stimulus arrays on the background of a multifocal array.MethodsThis apparatus is made of illumination and photographic optical systems separated by a mirror with a hole. In addition, it is made of a microperimetry optical system and an ERG optical system separated by a cold mirror. The device consists of an Edmund infrared camera EO‐50231, a lens with a 25‐mm focal length, a halogen lamp, an objective lens with a 50‐mm focal length, 4 double convex lenses with a 100‐mm focal length, 2 aperture stops, a mirror, a 45° cold mirror, an 8‐inch monitor and an artificial eye. We deployed a differential amplifier with gain 10, high‐pass filter with a 21.2‐Hz cut‐off frequency, 60‐Hz notch filter and two non‐inverting amplifiers with gains 1001 and 11. Moreover, we used the National Instruments' I/O device USB‐6212, the Nihon Kohden's plate electrode NE‐113A, the Nihon Kohden's electromagnetic shield sheet Y049 and the LabVIEW 2018 software for data retrieval. The background of the ERG software consists of 11 layers and 330 arrays and uses seven arrays as the examination target. The centre of these seven arrays has the same area, with an array directly placed under it on the background; and the system superimposes these arrays. We developed the ERG software, which was able to display the adjusted background from 18.0 to 30.0 mm and it almost did not have the delay time of a flicker stimulation as the frequency was changed from 10 to 100 Hz. The ERG software was shown on an HP Pavilion 32‐inch HDR display.ResultsAt the arbitrary position on the fundus, the superimposing ERG was able to measure all waveforms: a wave, b wave, c wave, and photopic negative response. Cone ERG and bright flash ERG were good.ConclusionsIt is expected that the superimposing ERG function would identify the retinal layer causing visual alterations at specific points throughout the retina. Further work towards pre‐clinical animal testing and clinical evaluation are required.

Fabrication of Dual-Focus Artificial Compound Eye with Improved Imaging Based on Modified Microprinting and Air-Assisted Deformation

Fabrication of Dual-Focus Artificial Compound Eye with Improved Imaging Based on Modified Microprinting and Air-Assisted Deformation

Polarization-perceptual anisotropic two-dimensional ReS2 neuro-transistor with reconfigurable neuromorphic vision.

Polarization is a common and unique phenomenon in nature, which reveals more camouflage features of objects. However, current polarization-perceptual devices based on conventional physical architectures face enormous challenges for high-performance computation due to the traditional von Neumann bottleneck. In this work, a novel polarization-perceptual neuro-transistor with reconfigurable anisotropic vision is proposed based on a two-dimensional ReS2 phototransistor. The device exhibits excellent photodetection ability and superior polarization sensitivity due to its direct band gap semiconductor property and strong anisotropic crystal structure, respectively. The fascinating polarization-sensitive neuromorphic behavior, such as polarization memory consolidation and reconfigurable visual imaging, are successfully realized. In particular, the regulated polarization responsivity and dichroic ratio are successfully emulated through our artificial compound eyes. More importantly, two intriguing polarization-perceptual applications for polarized navigation with reconfigurable adaptive learning abilities and three-dimensional visual polarization imaging are also experimentally demonstrated. The proposed device may provide a promising opportunity for future polarization perception systems in intelligent humanoid robots and autonomous vehicles.

Effect of eyelid-warming device on meibomian gland dysfunction

Background Meibomian gland dysfunction (MGD) has a significant effect on patients’ quality of life. Despite the numerous treatment options, it is still difficult to obtain complete relief of signs and symptoms. Blephasteam is an eyelid-warming device that is easy to use and standardized for treatment of MGD. Objective This study aimed to evaluate of the effect of Blephasteam on MGD compared with the traditional warm compresses. Patients and methods This is a prospective comparative interventional study that included 40 eyes of 20 patients with MGD. Patients were subdivided into two groups: in group I, warm compresses were applied to the eyelids twice daily for 20–30 min for 2 weeks, whereas in group II, the patients used the Blephasteam device three sessions per week for 2 weeks. Both groups received treatment by systemic tetracycline, topical antibiotic and steroid, and preservative-free artificial tears eye drops for 2 weeks. The patients were assessed before treatment and after 2 weeks, 1 month, and 3 months using the Standard Patient Evaluation of dry Eye Disease questionnaire for dry eye, breakup time test (invasive and noninvasive; IBUT and NIBUT), and the shape of the lipid layer of the tear film by a tearscope. Results Both groups showed statistically significant improvement regarding the dry eye symptoms, IBUT and NIBUT, and the lipid layer interferometry. However, the follow-up visits showed statistically significant better results in group II than in group I for the Standard Patient Evaluation of dry Eye Disease questionnaire (P=0.044, 0.001, and 0.001, respectively). In addition, the IBUT was statistically significantly better in group II than in group I during the follow-up (P=0.014, 0.007, and 0.002, respectively) as well as the NIBUT (P=0.043, P<0.001, and P<0.001, respectively). There was no statistically significant difference in interferometry between the two groups during the follow-up. Conclusions Both traditional warm compress and Blephasteam were effective in MGD treatment, but Blephasteam was more effective.

Ocular involvement in rheumatoid arthritis – literature review

Rheumatoid arthritis (RA) is the most common systemic autoimmune disease that can be associated with ocular complications – keratoconjunctivitis sicca, episcleritis, scle­ri­tis, corneal changes and retinal vasculitis. The purpose of the review is to illustrate the ocular mani­fes­ta­tions of RA, focusing on pathogenesis, clinical examination and the­ra­peutic management. Eye manifestations in RA benefit from the use of artificial tears, eye gels, ointments or topical nonsteroidal anti-inflammatory drugs or corticosteroids. Nonresponsive or severe forms should benefit from topical drops containing the supply of immunosuppressants or cy­clo­sporine A. Rheumatic disease-modifying medication (DMARDs) has been reported to be effective in patients with refractory or corticosteroid-dependent cases. Bio­lo­gi­cal substances – infliximab, adalimumab and ri­tu­xi­mab – can be used successfully in patients considered nonresponders to synthetic therapy. Surgical treatment is re­served for severe cases, which are associated with local com­pli­ca­tions. In conclusion, collaborative efforts between oph­thal­mo­lo­gists and rheumatologists in the assessment and treatment of patients with RA are essential for the effective management of any ocular complications that may occur. rheumatoid arthritis, ocular manifestations, specific therapy