A unified framework for glaucoma progression detection using Heidelberg Retina Tomograph images

Glaucoma, the second leading cause of blindness worldwide, is an optic neuropathy characterized by distinctive changes in the optic nerve head (ONH) and visual field. The detection of glaucomatous progression is one of the most important and most challenging aspects of primary open angle glaucoma (OAG) management. In this context, ocular imaging equipment is increasingly sophisticated, providing quantitative tools to measure structural changes in ONH topography, an essential element in determining whether the disease is getting worse. In particular, the Heidelberg Retina Tomograph (HRT), a confocal scanning laser technology, has been commonly used to detect glaucoma and monitor its progression.In this paper, we present a new framework for detection of glaucomatous progression using HRT images. In contrast to previous works that do not integrate a priori knowledge available in the images, particularly the spatial pixel dependency in the change detection map, the Markov Random Field is proposed to handle such dependency. To the best of our knowledge, this is the first application of the Variational Expectation Maximization (VEM) algorithm for inferring topographic ONH changes in the glaucoma progression detection framework. Diagnostic performance of the proposed framework is compared to recently proposed methods of progression detection.     

Automatic localization of the optic disc by combining vascular and intensity information

This paper describes a new methodology for automatic location of the optic disc in retinal images, based on the combination of information taken from the blood vessel network with intensity data. The distribution of vessel orientations around an image point is quantified using the new concept of entropy of vascular directions. The robustness of the method for OD localization is improved by constraining the search for maximal values of entropy to image areas with high intensities. The method was able to obtain a valid location for the optic disc in 1357 out of the 1361 images of the four datasets.     

Comparison of peripapillary and macular vascular density in primary open-angle glaucoma,pseudoexfoliation glaucoma,and normal control eyes

PurposeTo compare the optical coherence tomography angiography (OCT-A) of the macula, and optic disc in primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PXG), and normal eyes.MethodsIn this observational, cross-sectional study, Sixty–five eyes with POAG, 61 eyes of age, and mean deviation (MD) from standard automated perimetry matched PXG patients, and 45 normal control eyes underwent OCT-A using AngioVue, and optic disc-associated vessel density (VD), macular-associated VD, Foveal avascular zone (FAZ) area, FAZ perimeter (PERIM), and vessel density within a 300 μm wide region of the FAZ (FD) were compared between groups.ResultsPeripapillary OCT-A parameters were significantly different among normal, and glaucomatous eyes with the highest values in the control eyes, but none of the peripapillary OCT-A parameters except inside disc VD was statistically significantly different between the PXG eyes, and POAG eyes. Correlation analysis revealed significant correlation between mean retinal nerve fiber layer (RNFL) and peripapillary VD in control (r = 0.427, P = 0.006), PXG (r = 0.82, P<0.001), and POAG (r = 0.79, P<0.001) eyes.PXG eyes exhibited significantly lower superficial, and deep macular vessel densities in parafoveal and perifoveal regions compared with POAG eyes after adjustment (p<= 0.05). Overall, moderate /severe PXG eyes had lower superficial, and deep vessel densities in parafoveal and perifoveal regions compared to mild PXG.ConclusionPeripapillary VD (inside disc), and macular vessel densities (parafovea and perifovea) demonstrate a significant difference in age and glaucoma severity-matched POAG and PXG eyes. Moderate/advance glaucomatous eyes, exhibit significant damage to the superficial and deep macular vascular structures.     

颜色棋盘格图形视诱发电位的分析及应用

本文应用颜色棋盘格图形信号对正常眼对照(NC)组,高眼压(OH)组,原发性开角型青光眼(POAG)组作视诱发电位测试,对其波形进行了分析,并就三组的测试结果做了比较。NC组不同颜色信号的结果无显著性差异。OH组、POAG组黑-白与黑-红,黑-白与黑-兰有显著性差异。NC组与OH组,POAG组t测验除NC组与OH组的黑-白信号无显著性差异外,其余均呈显著性改变,尤以黑-红,黑-兰信号有非常显著性改变。根据测试结果,P1波潜时同一眼的黑-红减黑-白差值>4ms者POAG组29眼中有23眼占79%,OH组27眼中有15眼,占56%,而NC组仅占6%。这结果提示开角型青光眼早期视系统的功能变化有可能用于临床,做为原发性开角型青光眼的早期诊断综合分析的重要观察指标之一。     

Detection of neovascularization in retinal images using multivariate m-Mediods based classifier

Diabetic retinopathy is a progressive eye disease and one of the leading causes of blindness all over the world. New blood vessels (neovascularization) start growing at advance stage of diabetic retinopathy known as proliferative diabetic retinopathy. Early and accurate detection of proliferative diabetic retinopathy is very important and crucial for protection of patient's vision. Automated systems for detection of proliferative diabetic retinopathy should identify between normal and abnormal vessels present in digital retinal image. In this paper, we proposed a new method for detection of abnormal blood vessels and grading of proliferative diabetic retinopathy using multivariate m-Mediods based classifier. The system extracts the vascular pattern and optic disc using a multilayered thresholding technique and Hough transform respectively. It grades the fundus image in different categories of proliferative diabetic retinopathy using classification and optic disc coordinates. The proposed method is evaluated using publicly available retinal image databases and results show that the proposed system detects and grades proliferative diabetic retinopathy with high accuracy.     

军事飞行员原发性青光眼的医学鉴定分析

目的 探讨因原发性青光眼和可疑青光眼住院的军事飞行员的疾病特点、飞行结论 及放飞观察情况. 方法 对95例因青光眼或可疑青光眼住院的飞行员资料进行回顾性临床分析.结果 95例住院患者中56例诊断为原发性开角型青光眼(POAG),其中停飞15例,飞行暂不合格3例,飞行合格38例,放飞观察中延长飞行年限1～26年,平均6.36±1.43年.36例怀疑青光眼者进行青光眼排除检查,33例排除了青光眼,飞行合格;3例临床可疑,飞行暂不合格.3例诊断为高眼压症,飞行合格. 结论 飞行员最多见的青光眼类型是开角型青光眼;患POAG的飞行员若视功能稳定,在严密观察下能够继续飞行;早期发现和及时治疗是控制疾病的关键.     

Automated selection of major arteries and veins for measurement of arteriolar-to-venular diameter ratio on retinal fundus images

An automated method for measurement of arteriolar-to-venular diameter ratio (AVR) is presented. The method includes optic disc segmentation for the determination of the AVR measurement zone, retinal vessel segmentation, vessel classification into arteries and veins, selection of major vessel pairs, and measurement of AVRs. The sensitivity for the major vessels in the measurement zone was 87%, while 93% of them were classified correctly into arteries or veins. In 36 out of 40 vessel pairs, at least parts of the paired vessels were correctly identified. Although the average error in the AVRs with respect to those based on the manual vessel segmentation results was 0.11, the average error in vessel diameter was less than 1 pixel. The proposed method may be useful for objective evaluation of AVRs and has a potential for detecting focal arteriolar narrowing on macula-centered screening fundus images.     

Visual toxicity following intra-arterial chemotherapy with hydroxyethyl-CNU in patients with malignant gliomas

Summary We studied the effects of intra-arterial chemotherapy (IAC) with a new nitrosourea (hydroxyethyl-chloroethyl nitrosourea: HeCNU) on the visual system of 68 patients with malignant gliomas. The intra-arterial chemotherapy was given as a complementary treatment of glioma after surgery (19 patients), after tumor recurrence (28 patients) and as the preliminary treatment before radiotherapy (21 patients). Eleven patients (16%) suffered a visual complication after two or more courses of chemotherapy. The main visual symptoms included mild to major decrease of visual acuity and in some cases ocular pain, palpebral edema and conjunctival injection. The delay in onset of ocular symptoms from the last course of IAC varied from 1 week to 9 months. From ophthalmoscopic findings, visual field testing and fluorescein angiography, the visual symptoms presented by our patients could be related to ischemic optic neuropathy or retinal vasculopathy. None of the patients had hypertension, diabetes, cardiopathy or hematological disease. Statistical analysis failed to demonstrate a relationship between the occurrence of visual toxicity and patient age, number of courses of HeCNU, the vascular axis treated, total systemic dose or dose by carotid artery, suggesting a possible specific sensitivity of some patients to chemotherapy. The pathophysiology and the therapeutic implications of this visual toxicity are discussed.     

The use of radial symmetry to localize retinal landmarks

Locating the optic disc center and the fovea in digital fundus images is surprisingly difficult due to the variation range in color and contrast and the possible presence of pathologies creating bright spots or changing the appearance of retinal landmarks. These reasons make it difficult to find good templates of optic disc and fovea shape and color for pattern matching.In this paper we propose radial symmetry as the principal cue to locate both optic disc and macula centers. Centers of bright and dark circularly symmetrical regions with arbitrary radii, can be found robustly against changes in brightness and contrast by using the Fast Radial Symmetry transform. Detectors based on this transform coupled with a weak hypothesis on vessel density (optic disc intersects large vessels while the fovea lies in an avascular region), can provide a fast location of both OD and macula with accuracy similar or better than state-of-the-art methods. The approach has been chosen as the default technique for fast localization of the two landmarks in the VAMPIRE software suite.     

The assesment of retina and optic disc vascular structures in people who received CoronaVac vaccine

IntroductionSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that is responsible for the current coronavirus disease pandemic and the vaccines currently developed are administered to prevent this infection. CoronaVac is a vaccine produced by the inactivated virus method. Ocular side effects such as anterior uveitis, optic neuritis, vision loss, episcleritis, allergic reaction and paracentral acute middle maculopathy have been reported after receiving CoronaVac vaccine. We assume that with this study, we can identify potential changes in posterior segment structures and posterior segment vascular density of people who received CoronaVac vaccine with optical coherence tomography angiography (OCTA) device.Material methodForty healthcare professionals who applied to the Health Sciences University Antalya Training and Research Hospital Ophthalmology Clinic for routine eye control were included in the study. The subjects who do not have any systemic condition and would be administered CoronaVac vaccine were chosen to assess. OCTA images of the patients before and within 1 week after vaccination were captured, then retinal and optic disc vascular values, foveal avascular zone (FAZ), choriocapillary blood flow (CBF), subfoveal choroidal thickness (SCT) and retinal thickness were analyzed and compared.ResultsTwo of the 40 patients had burning and stinging in the eye (5%), two of the 40 patients had redness (5%) and itching (5%) in the eye. 36 patients did not have any ocular symptoms.No statistically significant difference was found in the retinal and optic disc vascular density values, FAZ, CBF, SCT and retinal thickness values ​​of the patients before and after vaccination.ConclusionThis is among the first studies in the literature to evaluate the changes in retinal and optic disc vascular values ​​in people who received CoronaVac vaccine. In this study, we observed that CoronaVac vaccine did not effect retinal and optic disc vascular density significantly.     

A Fronto-ethmoidal Sinus Mucocele presenting with optic disc edema

The frontal and anterior ethmoidal sinus mucoceles may enlarge progressively and invade into the orbit by destructing the bony walls of the sinuses leading to diplopia or proptosis, but it rarely result in optic nerve impairment. We report on a case of fronto-ethmoidal sinus mucoceles presenting with unilateral optic disc edema without visual disturbances. Ocular manifestations, radiographic techniques, and histopathological evaluation were used to make the diagnosis. Early diagnosis through a combination of ophthalmological examinations and radiographic techniques is imperative in patients with fronto-ethmoidal sinus mucoceles presenting with optic disc edema. It is important for the ophthalmologist to be aware of the ocular manifestations associated with sinus mucoceles to avoid misdiagnosis.     

Clinical case report: treatment of a central retinal vein occlusion with hyperbaric oxygen.

A case of retinal central vein occlusion (CRVO) in a 43-year-old man is presented in which hyperbaric oxygen (HBO2) was used as the only treatment method. CRVO is a relatively common cause of visual loss, with hypertension, diabetes, glaucoma and hypercoagulable conditions identified as risk factors. The patient in this report had none of these risk factors and declined treatments other than hyperbaric oxygen. HBO2 was effective in sustaining the ischemic retina and controlling retinal edema until the retina revascularized and vision stabilized. The initial visual acuity in the left eye was 20/200 (corrected), and after two hyperbaric treatments it was 20/30 (corrected). Following three months of HBO2 treatments the vision stabilized to 20/20 (corrected) in the affected eye. Treatment considerations in using HBO2 as adjunctive therapy for CRVO are early institution of treatment, and continuation of HBO2 until the retinal edema has resolved and vision has stabilized.     

Evaluation of optic nerve head in patients with small optic disc using oral isotretinoin

BackgroundIsotretinoin has a number of neurological and ocular side effects, but its effect on the optic nerve has not been demonstrated.PurposeTo investigate the effect of oral isotretinoin therapy on the peripapillary retinal nerve fibre layer thickness (RNFL) in patients with small optic disc area using optical coherence tomography (OCT).MethodsThis retrospective study included 55 patients taking 40 mg/day oral isotretinoin. The patients were grouped according to optic disc area. Patients with small optic disc area were included in group 1 and the others in group 2. RNFL thickness was measured by spectral domain OCT before the treatment, at the third month of the treatment, and at the third month after treatment.ResultsRNFL increased significantly in group1 in the third month of treatment compared to that before the treatment (P < 0.001); no significant change was observed in group 2 (P < 0.244).DiscussionOral isotretinoin treatment may be effective in patients with small optic nerve head. The presence of a small optic disc may increase the risk of adverse effects such as decreased dark adaptation, reduced vision, headache, or photophobia.ConclusionEvaluating the optic disc size before initiation of oral isotretinoin treatment may assist in planning patient treatment.     

Diffusion tensor imaging of the optic disc in idiopathic intracranial hypertension

Purpose

To study optic disc in idiopathic intracranial hypertension (IIH) with diffusion tensor imaging.

Methods

Prospective study was carried out on 31 consecutive patients with IIH and 17 age and sex-matched controls that underwent diffusion tensor imaging of optic nerve. Fractional anisotropy (FA) and mean diffusivity (MD) of optic disc were measured by two readers. Grades of papilledema and visual field defects were evaluated by ophthalmologist.

Results

FA of optic disc was significantly lower in IIH than controls (p?=?0.001) with excellent inter-observer agreement (K?=?0.93) of both readers. The cutoff FA used to differentiating IIH from controls were 0.28 and 0.29 with area under curve (AUC) of 0.921 and 0.914, accuracy 92% and 91%, and sensitivity 97% and 96%. MD of optic disc were significantly higher in IIH than in controls (p?=?0.001) with excellent inter-observer agreement (K?=?0.91) of both readers. The cutoff MD used to differentiating IIH from controls was 1.51 and 1.22?×?10^?3 mm²/s with AUC 0.943 and 0.922, and accuracy 94% and 92% respectively. FA of optic disc was significantly lower in early than advanced papilledema and visual field defects (p?=?0.001, 0.001) respectively. The MD of optic disc was significantly higher in early than advanced papilledema and visual field defects (p?=?0.001, 0.001) respectively.

Conclusion

Diffusion tensor imaging parameters of optic disc are non-invasive reliable imaging parameters that can be used for diagnosis of IIH and well correlated with papilledema and visual field defects.

     

炎症对玻璃体切割术预后的影响

玻璃体切割术是处理眼外伤的主要手段之一,但术后持久的炎症可能与视网膜脱离的发生有关。将活化巨噬细胞注入玻璃体切除后的兔眼,结果引起了纤维血管组织增生和牵拉性视网膜脱离(13/15眼),而在对照组仅有3眼发生。本实验提示使用抗炎药物并将手术创伤减少到最低限度,可以改善手术的预后。     

原发性开角型青光眼V1区皮层功能变化的功能MRI研究

目的 利用fMRI视网膜皮层映射技术研究原发性开角型青光眼(POAG)患者V1区皮层功能变化.方法 选取15例POAG患者及15名正常志愿者,利用视网膜皮层映射分区刺激和圆形黑白翻转棋盘格刺激采集fMRI数据.采用配对样本t检验比较POAG患者患侧眼与健侧眼V1区的fMRI反应、独立样本t检验比较健侧眼与匹配的正常人眼V1区的fMRI反应和激活.POAG患者患侧眼和健侧眼单独刺激时的V1皮层功能差异与视功能差异做线性相关分析.结果 (1)患侧眼接受刺激时V1区fMRI反应较健侧眼弱(t=4.757,P<0.01),患侧眼和健侧眼fMRI反应分别为(1.24±0.72)%、(2.18±0.93)%.患侧眼、健侧眼分别与其年龄、性别、眼侧别相匹配的正常人眼V1区fMRI反应进行比较:患侧眼较正常人眼反应弱(t=-3.011,P<0.01),患侧眼和匹配眼fMRI反应分别为(1.24±0.72)%、(2.01±0.65)%;健侧眼和匹配眼反应差异无统计学意义(t=0.742,P＞0.05),健侧眼和匹配眼分别为(2.18±0.93)%、(1.95±0.75)%.(2)患侧眼与健侧眼单独刺激的V1皮层功能差异与视功能差异存在线性负相关(r=-0.887,P<0.01).(3)患者的健侧眼与其年龄、性别、眼侧别相匹配的正常人眼比较,患者健侧眼V1激活较正常人眼小(t=-3.801,P<0.01),健侧眼和匹配眼V1激活面积指数分别为0.72±0.12、0.85±0.09.结论 青光眼存在皮层功能损害,而且青光眼皮层功能的损害与视觉功能的损害存在相关一致性;基于fMRI视网膜皮层映射分区的定位、定量测量是一种对青光眼视觉皮层功能变化临床随访、评估测量的有用方法,也是活体人青光眼视觉通路跨突触退变研究的潜在有用工具.     

Going to high altitude with preexisting ocular conditions

The goal of this paper is to review how preexisting ocular conditions may be affected by altitude exposure. Such preexisting conditions include dry eye problems, monocular visual loss, and potential problems following refractive surgery procedures, as well as the possible changes associated with some forms of retinal and optic nerve diseases. Although most such altitude-related visual difficulties are relatively minor, some have resulted in serious morbidity or even death at high altitude. This review will give the reader background regarding these potentially debilitating conditions in order to better prepare for exposure to high altitude environments.     

Biomechanical properties of optic nerve and retrobulbar structures with 2D and 3D shear wave elastography in patients affected by glaucoma

This study consists of an elastosonography evaluation of both eyes of 40 glaucomatous patients and 40 healthy subjects.We used shear wave elastography with a one-dimensional-array probe to capture two-dimensional images in order to study the optic nerve near the papilla, chorioretinal complex, lateral rectus muscle, and periorbital fat tissue. Furthermore, we used a two-dimensional array probe to capture three-dimensional images to study the optic nerve in toto with multilevel sampling. We obtained qualitative and quantitative data (“absolute” stiffness values). Then, we have investigated these tissue also measuring the “stiffness ratio” values.Statistically significant differences (p < 0.05), between glaucomatous patients and healthy patients, were noted in “absolute” stiffness values in the two-dimensional analysis at the emergence of the optic nerve and chorioretinal complex, and in the three-dimensional analysis at the emergence of the optic nerve (level I°). This result was supported by the statistically significant differences in the “stiffness ratio” values between the optic nerve and the adjacent adipose tissue, obtained both in two- and three-dimensional analyses.Data were subsequently compared with diagnostic tests currently used for glaucoma, which showed a sensitivity of 83% and specificity of 80% relative to those of elastosonography.We propose the use of elastosonography to verify the existence of pathological changes in the mechanical and elastic properties of peri-ocular structures and their variations as a complementary tool in the diagnosis of glaucoma and for follow-up during treatment.     

Parameter-free optic disc detection

The paper presents a simple, parameter-free method to detect the optic disc in retinal images. It works efficiently for blurred and noisy images with a varying ratio OD/image size. The method works equally well on images with different characteristics which often cause standard methods to fail or require a new round of training. The proposed method has been tested on 214 infant and adult retinal images and has been compared against hand-drawn ground truths generated by experts. It displays consistently high OD detection rates without any prior training or adjustment of the parameters.     

非孔源性视网膜脱离MRI诊断价值及原因探讨

目的:分析MRI在非孔源性视网膜脱离的应用价值,并探讨其致病原因.方法:收集因未发现裂孔而行MRI检查的非孔源性视网膜脱离患者24例,其中男性14例,女性10例,年龄21～85岁,平均51.5岁.全部病例经手术病理、临床综合诊断和随访证实.24例患者均采用头线圈行MRI检查,其中21例MRI增强;然后分析MRI影像及其致病原因.结果:非孔源性视网膜脱离表现为眼球内异常信号灶,V形13例(54%),弧形8例(34%),条状2例(8%),片状1例(4%),近端均连向视盘.非孔源性视网膜脱离,I_1WI表现为中等或稍高信号,T_2WI多呈相对低信号,也可呈等或高信号;增强后无强化表现.致病原因包括脉络膜黑色素瘤11例,外伤所致玻璃体出血3例,瘢痕或机化3例,脉络膜血管瘤2例,转移1例,脉络膜脱离1例,Coat病1例,异物术后1例,先天小眼球1例.结论:MRI不仅显示非孔源性视网膜脱离的特征性表现,而且对可能的致病原因作出正确诊断.