Ivermectin dosing based on physical appearance

Ivermectin is a safe and effective microfilaricide which has been shown to have a beneficial impact on some onchocercal eye lesions. Current requirements for the distribution of ivermectin are that patients be weighed, and that their dose be determined according to their weight. This requirement increases the cost of distributing the drug to communities in need of treatment and, when scales breakdown, may lead to the suspension of distribution. Data are presented on a simple, alternative method of dose assessment based on the physical appearance of the patient. Fifteen assessors achieved an overall level of agreement with the weight-based schedule of 86% on a sample of 6420 patients. The level of agreement varied between assessors, from 73% to 95%. About 6% of the population would have received doses outside the range of the current weight-based schedule. We believe that the current insistence that each individual's dose of ivermectin be determined by weighing will hamper efforts to distribute the drug to those most in need of it and that our data indicate that workers can be trained to distribute ivermectin safely without weighing every individual. We would welcome confirmation of our findings from other populations.     

Pseudovitreous fluid based on sodium carboxymethylcellulose

Various materials have been suggested for vitreous replacement following vitreoretinal surgery. We studied the use of a viscous physiologic solution based on sodium carboxymethylcellulose, a synthetic polymer structurally similar to hyaluronic acid. Following vitrectomy this pseudovitreal fluid was injected into the vitreous cavity of rabbits. The material appeared to be well tolerated during a six-month observation period.     

Texture discrimination based on global feature alignments

Three experiments are reported that examined the abilities of human observers to discriminate textures with identical distributions of orientation and spatial frequency. In Experiment 1, the stimuli consisted of low-pass filtered noise that was uniformly distributed and spatially isotropic. Observers were able to discriminate textures with identical image statistics when their frequencies were 1 cpd or less, but performance dropped off sharply for textures with higher frequencies. In Experiment 2, a novel procedure was employed with which it is possible to increase the high-frequency energy in the amplitude spectrum of a texture, while preserving the macroscopic alignments of its phase spectrum. The results reveal that this has little effect on performance, thus indicating that it is not spatial frequency per se that limits the abilities of observers to discriminate macroscopic texture patterns. When the phase spectra of these textures were randomly scrambled in Experiment 3, the frequency thresholds for discriminating textures reverted back to 1 cpd as was obtained in Experiment 1. These results provide strong evidence that human observers make use of two distinct procedures for discriminating patches of texture: One based on image statistics that is possible for all textures; and another based on macroscopic phase alignments that define features that are larger than 1°.     

Visual illusions based on single-field contrast asynchronies

A single-field contrast asynchrony refers to a stimulus configuration in which there is a single temporally modulated field and multiple sources of contrast information; the sources of contrast information modulate at different temporal phases or at different temporal frequencies. In this paper we show how single-field contrast asynchronies can lead to a wide variety of visual illusions. We investigate, in depth, the window shade/rocking disk configuration, in which a temporally modulated disk is surrounded by a split annulus (i.e., the top half is dark, and the bottom half is light). When the annulus is thick, the disk appears spatially inhomogeneous (shading); when the annulus is thin, the disk appears to rock back and forth (shifting). We measure the proportion of trials that a disk appears to shade or, on separate trials, appears to shift as a function of modulation amplitude, surround thickness, temporal frequency, and disk size. We account for the shading effects by postulating a combination of separate first- and second-order responses and/or a multi-scale spatial filtering process. We account for the shifting effects by examining four elemental motion conditions. For luminance modulation, the direction of the shift follows the same pattern as that produced by the rectified output of an array of spatial center-surround filters applied to the X, t plot. For equiluminant modulation, the direction of the shifts is consistent with a sequence-tracking (or third-order) motion response.     

Predicting visual fixations on video based on low-level visual features

To what extent can a computational model of the bottom-up visual attention predict what an observer is looking at? What is the contribution of the low-level visual features in the attention deployment? To answer these questions, a new spatio-temporal computational model is proposed. This model incorporates several visual features; therefore, a fusion algorithm is required to combine the different saliency maps (achromatic, chromatic and temporal). To quantitatively assess the model performances, eye movements were recorded while naive observers viewed natural dynamic scenes. Four completing metrics have been used. In addition, predictions from the proposed model are compared to the predictions from a state of the art model [Itti's model (Itti, L., Koch, C., & Niebur, E. (1998). A model of saliency-based visual attention for rapid scene analysis. IEEE Transactions on Pattern Analysis and Machine Intelligence 20(11), 1254-1259)] and from three non-biologically plausible models (uniform, flicker and centered models). Regardless of the metric used, the proposed model shows significant improvement over the selected benchmarking models (except the centered model). Conclusions are drawn regarding both the influence of low-level visual features over time and the central bias in an eye tracking experiment.     

Modeling the eye based on simulated refractive surgery

PURPOSE: To achieve three-dimensional modelizing of the eyeball (morphological and mechanical behavior) in order to simulate the impact of various refractive surgery techniques and to study the normal and pathological states of the eye. METHOD: Rebuilding the ocular shell is based on different kinds of imaging (MRI, ultrasound) including information provided by video topography. Image data are treated using suitable numerized filters that allow automatic segmentations of ocular globus edges. Reconstruction is based on specific mathematical functions (B-splines). The mechanical behavior of a reconstructed model is simulated by solving equations of linearized elasticity with the finitude elements method. RESULTS: Numerous simulations mimmed different refractive surgical techniques and, then validated the model. In addition, simulations of various pathologies allowed us to verify certain clinical hypotheses. CONCLUSION: This work, although still experimental, demonstrates the advantages of such simulations and will allow novice physicians an easier approach to different surgical techniques and will help them understand their effect. Furthermore, it might be useful for simulation of new surgical concepts even before their in vivo evaluation.     

Diabetic retinopathy identification based on multi-source-free domain adaptation

AIM: To address the challenges of data labeling difficulties, data privacy, and necessary large amount of labeled data for deep learning methods in diabetic retinopathy (DR) identification, the aim of this study is to develop a source-free domain adaptation (SFDA) method for efficient and effective DR identification from unlabeled data. METHODS: A multi-SFDA method was proposed for DR identification. This method integrates multiple source models, which are trained from the same source domain, to generate synthetic pseudo labels for the unlabeled target domain. Besides, a softmax-consistence minimization term is utilized to minimize the intra-class distances between the source and target domains and maximize the inter-class distances. Validation is performed using three color fundus photograph datasets (APTOS2019, DDR, and EyePACS). RESULTS: The proposed model was evaluated and provided promising results with respectively 0.8917 and 0.9795 F1-scores on referable and normal/abnormal DR identification tasks. It demonstrated effective DR identification through minimizing intra-class distances and maximizing inter-class distances between source and target domains. CONCLUSION: The multi-SFDA method provides an effective approach to overcome the challenges in DR identification. The method not only addresses difficulties in data labeling and privacy issues, but also reduces the need for large amounts of labeled data required by deep learning methods, making it a practical tool for early detection and preservation of vision in diabetic patients.     

Motion in depth based on inter-ocular velocity differences

Two different binocular cues are known for detecting motion in depth. One is disparity change in time and the other is inter-ocular velocity difference. In contrast to the well known fact of the use of the disparity cues, no evidence of contribution of inter-ocular velocity differences for detecting motion in depth has been reported. We demonstrate that motion in depth can be seen based solely on inter-ocular velocity differences using binocularly uncorrelated random-dot kinematograms. This indicates that the visual system uses monocular velocity signals for processing motion in depth in addition to disparity change in time.     

Functional brain imaging based on ERD/ERS

Sensory, cognitive and motor processing can result in changes of the ongoing EEG in form of an event-related desynchronization (ERD) or event-related synchronization (ERS). Both phenomena are time-locked but not phase-locked to the event and they are highly frequency-band specific. The ERD is interpreted as a correlate of an activated cortical area with increased excitability and the ERS in the alpha and lower beta bands can be interpreted, at least under certain circumstances, as a correlate of a deactivated cortical area. Spatial mapping of ERD/ERS can be used to study the dynamics of cortical activation patterns. Examples from a movement task are reported.     

New anti-angiogenic compound based on chemically modified heparin

Graefe's Archive for Clinical and Experimental Ophthalmology - The purpose of this study was to measure the anti-angiogenic effect of N-desulfated Re–N-acetylated, a chemically modified...     

基于深度学习的睑板腺腺体分割方法研究

目的:探讨应用深度学习技术解决睑板腺腺体自动分割问题的效果与价值。方法:采集并筛选出193幅红外睑板腺图像构建图像数据库,由3名临床医师对图像进行人工标记;引入UNet++网络与自动数据增广策略构建睑板腺腺体自动分割模型,采用精确率、敏感性、特异性、准确率和交并比分析该模型的可行性与有效性。结果:以人工标注结果为金标准,基于UNet++的睑板腺腺体自动分割模型取得94.31%的准确率,敏感性、特异性分别为82.15%和96.13%,腺体分割表现具有较好的稳定性,模型处理单张图像的平均用时仅为0.11s。结论:引入深度学习技术实现睑板腺腺体的自动分割,具有良好的准确性、稳定性和高效性,可服务于睑板腺功能障碍患者腺体形态参数的计算,辅助相关疾病的临床诊断和筛查,提高诊断效率。     

Graded orbital decompression based on severity of proptosis

OBJECTIVE: To study the results of orbital decompression based on the severity of preoperative proptosis. DESIGN: A retrospective noncomparative interventional case series. PARTICIPANTS: Thirty-nine orbits in 23 patients with thyroid-related orbitopathy at a university-based referral center. INTERVENTION: Graded orbital decompression was performed in all patients based on the severity of preoperative exophthalmometry. MAIN OUTCOME MEASURES: Exophthalmometry, visual acuity, margin-to-reflex distance, prism cover testing, and intraocular pressure. RESULTS: Mean proptosis reduction in all orbits was 6.4 +/- 2.7 mm (P < 0.01). In group 1 (preoperative exophthalmometry <22 mm), proptosis decreased with a mean of 4.8 +/- 1.3 mm (P < 0.01); mean proptosis reduction was 6.0 +/- 2.3 mm (P < 0.01) and 8.9 +/- 3.4 mm (P < 0.01) in group 2 (exophthalmometry between 22-25 mm) and group 3 (exophthalmometry >25 mm), respectively. In four of five eyes with compressive optic neuropathy there was an improvement of best-corrected visual acuity of 2 lines or more. Margin-to-reflex distance of the upper and lower lids and intraocular pressure were reduced in all groups. New-onset diplopia developed in two patients (8.7%); 13 of 15 patients (86.7%) who had diplopia preoperatively had persistent diplopia postoperatively. Two patients (13.3%) had relief of diplopia postoperatively. CONCLUSIONS: Graded orbital decompression based on the severity of preoperative exophthalmometry is useful to determine the type and amount of orbital surgery to be performed.     

基于虹膜膨隆过程的应力-应变关系的定量分析

目的　研究虹膜膨隆情况下虹膜变形与眼压之间的变化关系。方法　针对目前虹膜膨隆过程中描述其变形与前后房压差之间定量关系不清楚的情况,采用理论建模的方法并且根据虹膜膨隆典型形态,简化结构特征;依据力学原理,建立了虹膜应变与前后房房水压差之间的函数关系。结果　将虹膜膨隆简化为平面应变问题,虹膜的杨氏模量E不仅与虹膜半径R有关,更和应变系数K成正比。结论　给出了一种计算虹膜膨隆应变的简单方法,可以直接根据超声生物显微镜扫描结果计算虹膜组织的力学特性,为临床医生选择适时手术时机,防止闭角型青光眼患者失明提供重要的理论依据。     

Visualized analysis of research on myopic traction maculopathy based on CiteSpace

AIM: To analyze the global scientific output concerning myopic traction maculopathy (MTM) and to summarize the research frontiers and hot topics of MTM related researches. METHODS: Data were collected for bibliometric and visualization analyses from Web of Science (WOS) Core Collection. Exported records were analyzed for titles, publication years, research institutions, journal names, authors, keywords, and abstracts using CiteSpace software version 6.1. RESULTS: A total of 839 related studies were analyzed, the publication volume increased annually, with Asia the most active region of MTM research. Optical coherence tomography angiography, optical coherence tomography, macular hole, high myopia, macular buckling were identified as the focus of the current research. Progression, association, classification and shape were identified as the major research frontiers. CONCLUSION: MTM is a major cause of visual loss in pathological myopic eyes. During the preceding 17y, the number of annual publications in MTM research increased gradually. Studies on the progression nature of MTM, genome-wide association study and proper classification of MTM might still be the frontiers of MTM researches.     

A cluster and scotoma analysis based on empiric criteria

From a collection of 288 visual fields of glaucomatous or glaucoma suspects, 30 were selected at random and were analyzed by one expert interpreter. Visual field damage varied from nonexistent to severe. The interpreter defined clusters or scotomas subjectively according to adjacency criteria: adjacent test locations which exceeded a critical loss value were grouped as clusters or scotomas. A computer algorithm has been devised which simulates such evaluation methods. In general, a standard setting of several parameters produced a cluster display containing the same number of clusters as determined by the expert interpreter. Another display mode grouped clusters according to polygonal areas of a predetermined size (Voronoi diagram). Due to the broad selection of visual field defects, the specificity of the program with regard to various field decay patterns was small and it should thus be applicable to a broad spectrum of glaucomatous field damage.Supported by Swiss National Science Foundation Grant 32-30229.90     

Surgical strategies for fornix reconstruction based on symblepharon severity

PURPOSE: To identify surgical strategies of fornix reconstruction for symblepharon graded according to the length from the limbus to the lid margin, to the width, and to associated inflammation. DESIGN: Retrospective, comparative, interventional case series. METHODS: In 61 eyes with symblepharon, cicatrix lysis and amniotic membrane transplantation (AMT) were performed with sutures (n = 34) or fibrin glue (n = 27) together with (n = 47) or without (n = 14) intraoperative mitomycin C (MMC), plus fornix reconstruction using anchoring sutures without (n = 30) or with (n = 7) oral mucosal graft or with conjunctival autograft (n = 4). Overall, success was defined as an outcome of complete success (restoration of an anatomically deep fornix) or partial success (focal recurrence of scar), and failure was defined as the return of symblepharon. RESULTS: For a follow-up of 25 +/- 10.8 months, the overall success was achieved by the first attempt in 52 eyes (85.2%) and failure resulted in nine eyes (14.8%); however, the success rate improved to 59 eyes (96.7%) with additional attempts. At the first attempt, AMT alone achieved overall successes in 92.8% of grade I eyes and in 100% of grade II eyes. Additional anchoring sutures achieved successes in 100% of grade I eyes, 70% of grade II eyes, and 71.4% of grade III/IV eyes. Additional oral mucosa or conjunctival autograft achieved successes in 100% of grade III/IV eyes. The complete success was correlated positively with lower grades of symblepharon or intraoperative use of MMC, but negatively correlated with younger ages, canthal involvement, or use of anchoring sutures. Anatomic improvement was accompanied by reduction of preoperative conjunctival inflammation (n = 40), improved visual acuity (n = 14), improved ocular motility (n = 18), improved eyelid closure (n = 3), and feasibility of contact lens wear (n = 10). CONCLUSIONS: Successful outcome can be achieved by selectively deploying cicatrix lysis and AMT, intraoperative MMC, anchoring sutures, and oral mucosal or conjunctival autograft based on the severity of pathogenic symblepharon.     

A gradient-index ophthalmic lens based on Wood''s convex pseudo-lens

Although the Varilux type varifocal has been and still is very popular, research has been carried out on other methods of providing a progressive addition lens. This paper deals with the field of gradient-index optics. It includes a review of the literature related to the production of a gradient-index element and the theoretical analysis of concentric varifocals. A procedure is described to construct a varifocal lens, after that described by Wood in 1905, to produce lenses known as 'non-homogeneous cylinders' or 'pseudo-lenses'. The method is based on a diffusion process, taking place in half of the lens, and creates steps in the refractive index of the material. Experimental data are also given on the change of the spherical and cylindrical power, which indicate that the lens constructed is an optical system having a rotational symmetry in power, around a fixed point.