Optical Eyes Research Articles

Development of Augmented Reality Media to Improve Student Understanding of Optical Eyes System Materials

Optical material is material that is quite difficult for students because it has abstract concepts. Media that is considered an alternative solution is augmented reality. AR provides an effective learning experience because it displays 3D images so that it is easily accepted by students and makes students interested in learning. This study aims to develop augmented reality media to increase students' understanding of the eye optical system material. The type of research to be carried out in Research and Development, with the chosen development model being ADDIE. Product evaluation is carried out based on test results and product implementation. The population of this research is students of the Physics Education Study Program, FKIP UT, who are enrolled in the 2021.2-semester lectures and tutors for the Physics Education Study Program, FKIP UT. The research sample was students of the UT FKIP Physics Education Study Program who attended several 18 people (from UPBJJ UT Bogor, Jakarta, and Serang and tuweb tutors for the optics course). The data collection method consisted of administering a questionnaire. To determine the level of understanding of student material on system material eye optics, test results given to students were analyzed descriptively. Questionnaire analysis from tutors and students regarding the need for AR media was analyzed descriptively and quantitatively. The sampling technique used was random sampling, in which the entire population has the same rights and opportunities to be involved in research Based on the results of the needs analysis, it shows that 81% of students agree and need AR media to study the optical system of the eye, 72% of students agree that the material for the optical system of the watch has the potential to cause misconceptions if studied without using media. Based on the results of the needs analysis, consists of 3 main topics, namely regarding the structure of the eye, the process of seeing in the eye, and eye defects. The results of the trial analysis using AR media used a paired sample t-test to see the effectiveness of AR media. The results of the analysis of the paired sample t-test showed a Sig.2 tailed value > 0.05 so it can be concluded that there was a significant difference between before and after using AR media. In other words, it is easier for students to understand the material after being treated in the form of AR media on the concept of eye optics.

LONGITUDINAL ELLIPSOID ZONE AND OUTER RETINAL INTEGRITY DYNAMICS AFTER EPIRETINAL MEMBRANE SURGERY.

To quantify ellipsoid zone (EZ) changes in integrity after epiretinal membrane (ERM) surgery, correlate findings to visual acuity, and determine predictors for prognosis. A post hoc analysis of eyes undergoing ERM surgery pooled from the prospective DISCOVER intraoperative optical coherence tomography study and eyes undergoing conventional ERM surgery without intraoperative optical coherence tomography. Quantitative EZ features were extracted using a multilayer machine learning enabled automated segmentation platform after image analyst review/correction for segmentation accuracy. Visual acuity and EZ integrity were quantitatively assessed and correlated before and after ERM surgery. Multiple linear regression was performed to assess preoperative visual acuity and EZ features as predictors for improvement in visual acuity or EZ integrity. There were 177 eyes from 177 subjects that underwent ERM surgery from the DISCOVER and conventional arms. Improvement in visual acuity and multiple EZ integrity features was noted after ERM surgery, including EZ partial attenuation and EZ-retinal pigment epithelium (RPE) volume (P < 0.05). A reduction in EZ partial attenuation and increase in EZ-RPE central subfield thickness (EZ-RPE CST) was significantly correlated with improved visual acuity after ERM surgery (P < 0.05). More robust EZ-RPE CST at baseline predicted visual acuity improvement after ERM peel in regression modeling (β = 0.005, P < 0.05). Longitudinal assessment of EZ features demonstrates significant postoperative improvement in multiple EZ integrity metrics after ERM surgery. Improving EZ integrity was correlated to improving the visual acuity. Ellipsoid zone integrity and visual acuity were significant predictors in regression modeling and may have value in clinical prognostication.

Optimum thickness of GaAs top layer in AlGaAs‐based 850 nm VCSELs for 56 Gb/s PAM‐4 applications

We studied the influence of GaAs top-layer thickness on the small-signal modulation response and 56 Gb/s four-level pulse-amplitude modulation eye quality of 850 nm vertical-cavity surface-emitting lasers (VCSELs). We considered the proportionality of the gain-saturation coefficient to the photon lifetime. The simulation results that employed the transfer-matrix method and laser rate equations led to the conclusion that the proportionality should be considered for proper explanation of the experimental results. From the obtained optical eyes, we could determine an optimum thickness of the GaAs top layer that rendered the best eye quality of VCSEL. We also compared two results: one result with a fixed gain-saturation coefficient and the other that considered the proportionality. The former result with the constant gain-saturation coefficient demonstrated a better eye quality and a wider optimum range of the GaAs top-layer thickness because the resultant higher damping reduced the relaxation oscillation.

Stark trade-offs and elegant solutions in arthropod visual systems.

Vision is one of the most important senses for humans and animals alike. Diverse elegant specializations have evolved among insects and other arthropods in response to specific visual challenges and ecological needs. These specializations are the subject of this Review, and they are best understood in light of the physical limitations of vision. For example, to achieve high spatial resolution, fine sampling in different directions is necessary, as demonstrated by the well-studied large eyes of dragonflies. However, it has recently been shown that a comparatively tiny robber fly (Holcocephala) has similarly high visual resolution in the frontal visual field, despite their eyes being a fraction of the size of those of dragonflies. Other visual specializations in arthropods include the ability to discern colors, which relies on parallel inputs that are tuned to spectral content. Color vision is important for detection of objects such as mates, flowers and oviposition sites, and is particularly well developed in butterflies, stomatopods and jumping spiders. Analogous to color vision, the visual systems of many arthropods are specialized for the detection of polarized light, which in addition to communication with conspecifics, can be used for orientation and navigation. For vision in low light, optical superposition compound eyes perform particularly well. Other modifications to maximize photon capture involve large lenses, stout photoreceptors and, as has been suggested for nocturnal bees, the neural pooling of information. Extreme adaptations even allow insects to see colors at very low light levels or to navigate using the Milky Way.

Cataract type in mouse exposed to moderate doses of ionizing radiation depends on mouse age at irradiation

AbstractOne noxious agent for cataract formation is ionizing radiation (IR). For doses till or equal 2 Gy it is still unclear, whether opacification occurs and if, how cataract type depends on the animals age at irradiation. Wild‐type and heterozygous Ercc2+/‐ mice were whole‐body irradiated by 0.5 Gy, 1 Gy and 2 Gy of γ‐radiation (dose rate = 0.3 Gy/min), 10 weeks after birth (P70). Another cohort was exposed to 2 Gy, 2 days after birth (P2). All cohorts were investigated by optical coherence tomography (OCT) and eyes were collected for histology after death. OCT revealed frequent lens alteration in the mice irradiated at P2 and P70. These lesions were only subcapsular located in P70 mice and are dose‐dependent in size. Mice irradiated at P2 showed scattering structures within the posterior cortex, 8.5 mth after irradiation. At least 80% of the irradiated animals displayed at least mild posterior cortical cataracts. Histology of irradiated eyes (P70) unravelled the OCT‐detected lesions as cataractous accumulations of enlarged fibre cells, accompanied by subcapsular placed cells with nuclei. Lesions of P2 mice displayed no correlate to the in vivo data. Therefore, we conclude that IR leads to lens opacification in a dose‐dependent manner and its magnitude correlates strongly with age at irradiation. These results help to assess the sensibility of eye lenses to IR in case of exposure. The LDLensRad project received funding from Euratom in the framework of CONCERT, grant No 662287.

A 4 × 14-Gbps/ch VCSEL array driving ASIC in 65 nm CMOS for high-energy physics experiments

This paper presents the design and test results of a 4 × 14 Gb/s vertical cavity surface emitting laser (VCSEL) array driver VLAD14 fabricated in 65 nm CMOS technology. A novel output driving stage in VLAD14 is proposed to improve the bandwidth comparing to the conventional structure. VLAD14 outputs a 2 mA bias current and a 6 mA modulation current with a power consumption of 52 mW/ch when working at 14 Gbps/ch. The driver die has been tested with the VCSEL array load and wide-open optical eyes have been captured at 14 Gbps/ch.

Nonlinear optical absorption of SnX2 (X = S, Se) semiconductor nanosheets

Tin-based dichalcogenides such as SnS2 and SnSe2 have attracted wide attention due to their significant potential for the next-generation optoelectronic and photonic devices in nanotechnology. We investigate the nonlinear absorption of SnS2 and SnSe2 nanosheets using the Z-scan technique with nanosecond pulse and picosecond pulse at 532 nm for the first time. Z-scan measurement reveals that SnS2 nanosheets dispersions exhibit reverse saturable absorption (RSA) behavior under different pulses, which is in contrast to the saturable absorption (SA) observed in the SnSe2 nanosheets dispersions resulted from different band gaps. The nonlinear absorption coefficient (β) and the figures of merit (FOM) of SnS2 dispersed in ethanol with linear transmittances of 0.75 at input energy of 6.16 μJ in the nanosecond regime are 12.78 × 10−10 m/W and 8.71 × 10−11 esu⋅cm, respectively. As for SnSe2 nanosheet dispersions, β and FOM are −12.58 × 10−10 m/W and 11.98 × 10−11 esu⋅cm at the same input energy, respectively. The RSA behavior coupled to the smaller optical limiting threshold Fth (0.23 J/cm2) proves SnS2 a promising 2D material for protecting sensitive optical components or eyes from laser-induced damage. The SA performance indicates SnSe2 nanosheets prospective candidates for high-performance nanoscale nanophotonic devices like optical switches.

SWDM PAM4 Transmission Over Next Generation Wide-Band Multimode Optical Fiber

Two system transmission experiments are reported which indicate the feasibility of transmitting an aggregated speed of >200 Gb/s over a single next-generation wide-band multimode optical fiber (NG-WBMMF) using a shortwave wavelength division multiplexing (SWDM) and a four-level pulse amplitude modulation (PAM4), using optics rated for 25 Gb/s NRZ operation. The first experiment leverages predistorted KR4 51.5625 Gb/s electrical PAM4 signaling generated by an arbitrary waveform generator to drive SWDM TOSAs at 850, 880, 910, and 940 nm. The received optical PAM4 signals are then post processed offline with linear equalizers to improve the eye quality. Detailed analysis of the height and width of the received optical eyes indicates an aggregated 206.25 Gb/s speed is achievable on a single NGWBMMF beyond 150 m. In the second experiment, a commercial PAM4 IC evaluation kit with real-time digital signal processing is adopted to generate and detect PAM4 signals at KP4 FEC rate of 53.125 Gb/s per wavelength. The SWDM wavelength range is extended with additional tests at 980 nm. Pre-FEC BER below threshold of 2.4 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> is achieved up to 300 m across all five wavelengths demonstrating an aggregated speed of 265.625 Gb/s over a single MMF.

Four 45 Gbps PAM4 VCSEL based transmission through 300 m wideband OM4 fiber over SWDM4 wavelength grid.

We demonstrate successful transmission of four 45 Gbps PAM4 single-channels through OM4 multimode fibers (MMFs) and wideband MMF using a PAM4 PHY chip and four vertical cavity surface emitting lasers (VCSELs) with wavelengths ranging over short wavelength division multiplexing (SWDM) grid. Real-time bit error ratios (BERs) < 2 × 10-4 were achieved for all four 45 Gbps PAM4 SWDM grid channels over 100 m, 200 m, and 300 m of wideband OM4 MMFs. All four channel received PAM4 optical eyes are shown after propagating through 100 m, 200 m, and 300 m of wideband OM4 as well as 100 m and 200 m conventional OM4 MMFs. The measured BERs as a function of the inner eye optical modulation amplitudes (OMAs) are shown for all four SWDM grid channels. Inner eye OMAs ranged from -16.2 dBm to -13.5 dBm for different channels over different OM4 MMF types at the KP4 BER threshold of 2 × 10-4.

P-193L:Late-News Poster: Everybody Can Improve Motion Image Quality of One's LCD by Only Visual Inspection

This paper proposes a novel method to find out optimum overdrive (OD) values through only users' visual inspection. To investigate the relation between OD values measured from optical equipment and human eyes, three scrolling bar width (Viewing angle) and three difference values from the measured OD value (Delta) are used in the experiment. We found that people distinguish delta 1 when the viewing angle of scrolling bar was 4° is used. We propose an application of proposed pattern to a smart device. Users can optimize the OD values quickly and easily with their own eyes without any knowledge about OD technology.

Ray-matrix analysis for integrative ommatidium of bionic optical compound eyes

A new model of integrative ommatidium for bionic optical compound eye is proposed in this paper. The structure of the integrative ommatidium for bionic optical compound eye is constructed. The ray matrix of the integrative bionic optical compound eyes is deduced detailedly with ray-matrix method, and the principle points and focal points of the integrative bionic compound eye are calculated. The ray matrix of the integrative bionic compound eye is related tightly with the length of the cylinder waveguide part, so as the image principle point and the image focal point. The length of the cylinder waveguide has no influence on the position of the object principle point and the object focal point of the integrative bionic compound eye. However, difference length of the cylinder waveguide will lead to different positions of the image principle point and image focal points. Self-focus effect can be employed to fabricate the integrative bionic optical compound eyes with some nonlinear optical polymer.

Theoretical and experimental research on error analysis and optimization of tool path in fabricating aspheric compound eyes by precision micro milling

Structure design and fabricating methods of three-dimensional (3D) artificial spherical compound eyes have been researched by many scholars. Micro-nano optical manufacturing is mostly used to process 3D artificial compound eyes. However, spherical optical compound eyes are less at optical performance than the eyes of insects, and it is difficult to further improve the imaging quality of compound eyes by means of micro-nano optical manufacturing. In this research, nonhomogeneous aspheric compound eyes (ACEs) are designed and fabricated. The nonhomogeneous aspheric structure is applied to calibrate the spherical aberration. Micro milling with advantages in processing three-dimensional micro structures is adopted to manufacture ACEs. In order to obtain ACEs with high imaging quality, the tool paths are optimized by analyzing the influence factors consisting of interpolation allowable error, scallop height and tool path pattern. In the experiments, two kinds of ACEs are manufactured by micro-milling with different too path patterns and cutting parameter on the miniature precision five-axis milling machine tool. The experimental results indicate that the ACEs of high surface quality can be achieved by circularly milling small micro-lens individually with changeable cutting depth. A prototype of the aspheric compound eye (ACE) with surface roughness (R a) below 0.12 μm is obtained with good imaging performance. This research ameliorates the imaging quality of 3D artificial compound eyes, and the proposed method of micro-milling can improve surface processing quality of compound eyes.

Adjusting a light dispersion model to fit measurements from vertebrate ocular media as well as ray-tracing in fish lenses

Color dispersion, i.e., the dependency of refractive index of any transparent material on the wavelength of light, has important consequences for the function of optical instruments and animal eyes. Using a multi-objective goal attainment optimization algorithm, a dispersion model was successfully fitted to measured refractive indices of various ocular media and the longitudinal chromatic aberration determined by laser-scanning in the crystalline lens of the African cichlid fish, Astatotilapia burtoni. The model describes the effects of color dispersion in fish lenses and may be applicable to the eyes of other vertebrates as well.

SU-FF-T-512: Reporting and Assessing Radiation Damage of Normal Structures in Radiotherapy

Purpose: To verify the feasibility of reporting and assessing the radiation damage of normal structures using the equivalent uniform dose (EUD). Material and methods: The EUD concept has been used to assess and report radiotherapy of human cancer. We proposed to use the EUD to document and assess the collateral damage of radiotherapy to normal structure. Utilizing the differential dose volume histogram (d‐DVH) obtained from the clinical treatment planning system and the linear‐quadratic radio‐response model, we calculated the average normal cell survival fraction of normal structures of 15 patients treated by intensity modulated radiotherapy and field‐in‐field techniques. From the average survival fraction, we derived the EUD. For normal tissues, α /β=3.1 Gy was used. Three sets of model parameters with α = 0.366 Gy−1, 0.211 Gy−1 and 0.108 Gy−1 were used to represent radiosensitive, moderate radiosensitive and radioresistant tissues, respectively. Results: The EUDs of the optical nerve, eyes,brain stem, chiasm, glottis, cochlea, heart and spinal cord were calculated. The EUDs of each normal structure showed large variations from the plans of different patients although the prescription dose was the same. For the head‐neck cancer with 60 Gy dose, if critical organs are treated as the radiosensitive normal tissue, the EUD ranges from 4.9 to 6.7 Gy for brain stem, from 2.6 to 3.0 Gy for optic nerve, and from 2.3 to 2.6 Gy for the average of eyes. The EUDs of all structures with different radio‐sensitivities were evaluated. Conclusions: The results suggest that EUD can be used to document and evaluate the radiation damage to normal structures, though some organs like spinal cord might be over‐ or under‐contoured by oncologists thus provide inaccurate evaluation. A unified contouring policy and the EUD concept could provide a quantitative indication for evaluating radiation damage to those normal structures.

Burst-mode optical transmitter with DC-coupled burst-enable signal for 2.5-Gb/s GPON system

In this paper, first burst-mode transmitter for 2.5-Gb/s gigabit-capable passive optical networks (GPON) system is evaluated. Small form factor (SFF) type optical network unit (ONU) generates 2.5-Gb/s optical eyes with commercial distributed feedback-laser diode (DFB-LD). For the fast burst signal access, burst enable (BEN) connection on the evaluation board utilizes DC-coupling configuration. Resultant optical output waveform shows 16.30dB extinction ratio with wide eye opening for GPON mask test. No significant eye degradation is detected in high temperature operation and after 10km distance transmission. Proposed GPON ONU successfully shows fast timing characteristics of 2.17nsec for Tx enable stage and 1.17ns for Tx disable stage.

Effectiveness of noncoplanar IMRT planning using a parallelized multiresolution beam angle optimization method for paranasal sinus carcinoma

To determine the effectiveness of noncoplanar beam configurations and the benefit of plans using fewer but optimally placed beams designed by a parallelized multiple-resolution beam angle optimization (PMBAO) approach. The PMBAO approach uses a combination of coplanar and noncoplanar beam configurations for intensity-modulated radiation therapy (IMRT) treatment planning of paranasal sinus cancers. A smaller number of beams (e.g. 3) are first used to explore the solution space to determine the best and worst beam directions. The results of this exploration are then used as a starting point for determining an optimum beam orientation configuration with more beams (e.g. 5). This process is parallelized using a message passing interface, which greatly reduces the overall computation time for routine clinical practice. To test this approach, treatment for 10 patients with paranasal sinus cancer was planned using a total of 5 beams from a pool of 46 possible beam angles. The PMBAO treatment plans were also compared with IMRT plans designed using 9 equally spaced coplanar beams, which is the standard approach in our clinic. Plans with these two different beam configurations were compared with respect to dose conformity, dose heterogeneity, dose-volume histograms, and doses to organs at risk (i.e., eyes, optic nerve, optic chiasm, and brain). The noncoplanar beam configuration was superior in most paranasal sinus carcinoma cases. The target dose homogeneity was better using a PMBAO 5-beam configuration. However, the dose conformity using PMBAO was not improved and was case dependent. Compared with the 9-beam configuration, the PMBAO configuration significantly reduced the mean dose to the eyes and optic nerves and the maximum dose to the contralateral optical path (e.g. the contralateral eye and optic nerve). The maximum dose to the ipsilateral eye and optic nerve was also lower using the PMBAO configuration than using the 9-beam configuration, although this difference was not significant. The mean doses to the optic chiasm and brain are marginally lower using the PMBAO configuration than using 9-beam configuration. The maximum doses to the optic chiasm and brain are the same with the PMBAO configuration and the 9-beam configuration. Parallelized multiple-resolution beam angle optimization with an optimized noncoplanar beam configuration is an effective and practical approach for IMRT treatment planning. Five-beam treatment plans optimized using the PMBAO are at least equivalent to, and overall better than, the plans using 9 equally spaced coplanar beams.

The visually controlled prey-capture behaviour of the European mantispid Mantispa styriaca.

Mantispids (Mantispa styriaca) are predatory insects; on bright sunny days, they wait in ambush for insect prey. The prey is captured as soon as it is within reach by means of lightning-speed strikes with the powerful forelegs. The strikes can take less than 60 ms. The mantispid accomplishes this almost as effectively as the larger praying mantis, which occupies a similar habitat, even though the praying mantis has apposition eyes with a high-resolution fovea, whereas the mantispid has unspecialized optical superposition eyes. Mantispa styriaca reacts to an item of prey when the latter covers a critical visual angle. The detection of prey immediately triggers adjustment reactions in the mantispid, which attempts to position the prey item in the visual field of both eyes and in the capture zone. Irrespective of the size of the prey, the capture reaction of the mantispid is always triggered if the distance to the prey falls below a certain critical value. As indicated by the analysis of individual video frames, immediately before an aimed strike, the item of prey is always positioned exactly in the centre of the binocular field of vision in the extended midsagittal plane of the mantispid's head. The strike may be triggered by the ommatidia of the left and right eyes, the lines of sight of which converge precisely on this region. The principal conclusion to be drawn is that the prey-capture behaviour of the mantispid appears to be based on a triangulation mechanism.

Responses of Insects to Polarized Light in the Presence of Dark Reflecting Surfaces

THE ways in which arthropods, such as bees1–3, ants4,5, Diptera6, insect larvae7, Cladocera8,9, Amphipoda10 and Decapoda11, orientate in respect to the plane of vibration of polarized light are controversial. Some authors have investigated by optical and electrophysiological means various arthropod eyes and their elements for the properties of an analyser12,13, either those of a Nicol prism or those of some internal reflexion device; whereas others have been more concerned with external visual conditions3 in which orientation to polarized light is observed, and have tried to explain it on the basis of mere brightness discrimination. The present communication has followed the latter approach and was based on the following considerations.