Automated diagnosis of diabetic retinopathy and glaucoma using fundus and OCT images

ABSTRACT: We describe a system for the automated diagnosis of diabetic retinopathy and glaucoma using fundus and optical coherence tomography (OCT) images. Automatic screening will help the doctors to quickly identify the condition of the patient in a more accurate way. The macular abnormalities caused due to diabetic retinopathy can be detected by applying morphological operations, filters and thresholds on the fundus images of the patient. Early detection of glaucoma is done by estimating the Retinal Nerve Fiber Layer (RNFL) thickness from the OCT images of the patient. The RNFL thickness estimation involves the use of active contours based deformable snake algorithm for segmentation of the anterior and posterior boundaries of the retinal nerve fiber layer. The algorithm was tested on a set of 89 fundus images of which 85 were found to have at least mild retinopathy and OCT images of 31 patients out of which 13 were found to be glaucomatous. The accuracy for optical disk detection is found to be 97.75%. The proposed system therefore is accurate, reliable and robust and can be realized.     

光学相干层析成像的视网膜层状结构自动分割

目的利用算法实现对视网膜层状结构的自动分割及定量分析是光学相干层析成像技术应用于青光眼及视网膜病变早期诊断的关键。现存处理方法对图像质量要求较高且可靠性不高。该文拟利用改进的非线性复合扩散滤波等方法解决这个问题。方法首先对自主搭建的OCT系统获得的20幅视网膜图像,通过自动阈值、改进的非线性复合扩散滤波、形态学操作、峰值探测等综合算法,进行分割,比较准确的分割出内界膜（ILM）、外核层（ONL）、内节层和外节层（IS/OS）以及视网膜色素上皮与脉络膜层（RPE_ChCap）边界,最后测量得到视网膜的厚度。结果本算法对视网膜的分割与专家手动测量有较好的一致性,视网膜中心凹测量结果与Zeiss Stratus OCT视网膜中心厚度212±20μm数据一致。结论该文提出的算法有希望应用于临床视网膜疾病的诊断。     

光学相干断层扫描用于黄斑前膜临床诊治的探讨

目的探讨黄斑区增殖膜的光学相干断层扫描(Optical Coherence Tomography OCT)图像特征及临床诊断和术后评估价值。方法对在我院眼底检查拟诊或诊断为黄斑部视网膜患者38例38眼术前及术后行OCT检查。结果黄斑部视网膜前膜的OCT图像表现为视网膜表面厚薄不一的高反光带，或紧贴于黄斑表面，或与其部分相连。绝大多数黄斑中心凹变浅，厚度增加。术后黄斑区视网膜前膜消失，部分病例黄斑区色素上皮损害或黄斑部水肿。结论OCT可以直接客观地显示黄斑前膜及手术后黄斑部各种组织结构的改变，为黄斑前膜的临床诊断、手术效果及治疗评价提供了更加准确可靠的信息。     

频域OCT在病理性近视眼黄斑区神经上皮层厚度检测中的分析研究

目的应用频域OCT（光学相干断层扫描成像,Optical coherence tomography）技术分析研究病理性近视眼黄斑区视网膜神经上皮层厚度的变化特点。方法选取2012年2—12月在该院眼科行黄斑区频域OCT检查的病理性近视眼患者63例（63眼）作为观察组和正常眼患者54例（54眼）作为对照组,对其黄斑区视网膜进行测量,记录黄斑区9个分区的视网膜神经上皮层的平均厚度。结果 A1、A5区察组（病理性近视眼组）和对照组（正常眼组）之间的差异均无统计学意义（均为P〉0.05）;A2、A3区观察组（病理性近视眼组）均低于对照组（正常眼组）,P〈0.05,两组间的差异均有统计学意义;A4、A6、A7、A8、A9区,观察组（病理性近视眼组）均低于对照组（正常眼组）,P〈0.01,两组间的差异均有显著的统计学意义。结论病理性近视对视网膜特别是黄斑部的影响是确实存在的,频域OCT能够精确量化该厚度的变化。     

光学相干断层扫描定量糖尿病性黄斑水肿的黄斑厚度及与视功能相关分析

目的 观察糖尿病性黄斑水肿(DME)的光学相干断层扫描(OCT)临床特征,并探讨其与视功能改变的相关性.方法 40例49眼DME患者(DME组)及31例31眼无DME患者(对照组)分别应用OCT进行黄斑厚度定量分析,同时采用图形视觉诱发电位(P-VEP)及黄斑10°视野平均缺损(MD)指数检查视功能,根据DME组有无合并增生型糖尿病视网膜病变分为A组(非增生型糖尿病视网膜病变+DME,30眼)和B组(增生型糖尿病视网膜病变+DME,19眼).结果 DMEOCT图像定量分析发现,DME组黄斑厚度[(299.25±63.87)μm]较对照组[(204.35±37.94)μm]增厚,且视力、MD指数受损更为严重,其差异有统计学意义(P＜0.05).A组与B组的黄斑厚度、视力、MD指数比较差异均无统计学意义(P＞0.05);OCT黄斑厚度与视力存在线性负相关(r=-0.437,P＜0.05);OCT黄斑厚度与MD指数存在线性正相关(r=0.441,P＜0.05).结论 OCT为评估DME的发生、发展及疗效判断提供了一种有效、客观的检测手段,随着黄斑厚度的增加,视功能指标中视力下降、黄斑10°视野受损程度加重.

Abstract：

Objective To explore the clinical features of diabetic macular edema (DME) with optical coherence tomography (OCT) and correlation with visual function. Methods Forty-nine eyes from 40 patients with DME (DME group) and 31 eyes from 31 patients without DME (control group) were examined with OCT,pattern reversal visual evoked potentials (P-VEP),macular perimetry. According to proliferative diabetic retinopathy (PDR), 49 eyes with DME were divided into group A (without PDR, 30eyes) and group B (with PDR, 19 eyes). Results The retinal macular thickness of central fovea in DME group [(299.25±63.87)μm] was more than that in contol group [(204.35 ± 37.94)μm], visual acuity and macular visual field in DME group were significantly different than those in control group, respectively (P ＜ 0.05). The retinal macular thickness of central fovea,visual acuity and visual field were no significant differences between group A and group B (P＞0.05). OCT macular thickness and visual correlation coefficient was -0.437(P＜ 0.05 ); OCT macular thickness and mean defect correlation coefficient was 0.441(P ＜ 0.05). Conclusions OCT can provide a useful tool for monitoring the occurrence and development of DME, can assess the response to treatment. With increasing of the macular retinal thickness, the visual acuity and macular visual field of visual function are more damaged.     

An introduction to OCT in retinal disease

Ocular coherence tomography (OCT) has been available to ophthalmologists for many years and has had a significant impact on the diagnosis and treatment of many eye conditions. This fast and non-invasive way to image the eye has had a considerable effect on ophthalmic photography services. OCT can be used to assess the structure of the cornea, iris, anterior chamber, optic nerve and retina. This article focuses upon its use in retinal conditions and explores how the technique is used to aid treatment and diagnosis.     

傅立叶光学相干断层扫描测量黄斑区节细胞复合体及视网膜神经纤维层厚度对青光眼的诊断意义

目的 探讨黄斑区节细胞复合体（macular ganglion cell complex,mGCC）和视盘周围视网膜神经纤维层（peripapillary retinal nerve fiber layer,pRNFL）厚度在青光眼中的变化情况及诊断能力.方法 选择本院眼科门诊成年患者,所有受试者均接受青光眼常规项目检查.使用傅立叶光学断层扫描（optic coherence tomography,OCT）测量pRNFL及mGCC各参数.结果 受试者共116例（116眼）,包括正常组51例（44.0%）,早期青光眼组30例（30.2%）,进展期青光眼组35例（25.9%）,正常组、早期及进展期青光眼组的pRNFL、mGCC各参数的差异均有统计学意义（F=83.022、97.361、27.899、79.585、140.686、119.166、116.234、90.855、64.341、133.064,P＜0.01）.对于早期青光眼,除鼻侧之外（P＞0.05）,其余pRNFL及所有mCCC参数的受试者曲线下面积（Area under Receive Operated Curve,AROC）差异均有统计学意义（pRNFL：0.796±0.049;mGCC：0.748±0.055,P＜0.05）.对于总体青光眼,所有pRNFL及mGCC参数的AROC差异均有统计学意义（pRNFL：0.889±0.029;mGCC：0.862±0.034,P＜0. 01）.经AROC两两比较,除了颞侧、上方pRN-FL厚度较mGCC中局部丢失体积（focal loss of volume,FLV）具有较好的诊断能力（P＜0.05）,大部分pRNFL及mGCC参数之间的诊断能力差异无统计学意义（P＞0.05）.结论 在傅立叶OCT中,pRNFL仍是青光眼最主要检测方法,mGCC可作为一种有用的青光眼补充诊断手段.     

河北怀来地区老年人视力状况及影响因素分析

目的分析影响河北怀来地区老年人视力的主要因素。方法对2010年1月~2012年12月在河北怀来县医院眼科门诊就诊的70岁以上的老年人行眼科常规查体,对矫正视力低于1.0的患者行直接、间接检眼镜检查、视野、眼底荧光血管造影(FFA)、吲哚青绿脉络膜血管造影(ICGA)、光学相干断层扫描(OCT)等检查,找出病因。结果共有2960人(5920眼)参与检查,其中白内障4410眼(74.50%),老年性黄斑变性(AMD)1440眼(24.32%),青光眼252眼(4.25%),单纯性视神经萎缩133眼(2.25%),眼底视网膜病变(糖尿病视网膜病变、视网膜静脉阻塞等)146眼(2.47%)。影响视力的主要原因是白内障、AMD、青光眼、视神经萎缩及眼底视网膜病变。结论老年人眼部疾病明显增多,加强宣传眼病防治知识可有效改善老年人的生活质量。     

FEMLAB对OCT在脑外科手术中应用可行性的仿真分析

光学相干层析技术是一种高分辨率成像方法。它是一种无损伤、非介入、非离子辐射的探测技术，具有较高的空间分辨率。有限元分析（FEA）是用于工程科学的重要工具，FEMLAB（Finite Element Modeling Laboratory）是基于偏微分方程的对科学和工程问题进行建模和仿真计算的交互式系统。本文简要介绍了OCT成像技术的原理及FEMLAB的应用步骤，重点用FEMLAB软件对脑组织内光场的分布情况进行分析，从而利用分析结果论证OCT成像在脑外科手术中应用的可行性。     

武汉市武昌区中小学教师黄斑光学相干断层扫描应用研究

目的探讨黄斑光学相干断层扫描(optical coherence tomography,OCT)在武汉市武昌区中小学教师眼部体检中的应用价值。方法选取2018年9至12月在武汉大学人民医院健康管理中心体检的武昌区中小学教师共3495人,其中男1130人,女2365人,年龄22~93岁,入选对象按年龄分为3组,均完成视力、裂隙灯、直接检眼镜及黄斑部OCT的检查。采用卡方检验分析检出率前十位眼病及阳性发现在不同年龄段各组间的差异,分析OCT检查与直接检眼镜检查对黄斑病变检出率的差异。结果眼科异常检出率为70.76%(2473/3495)。<40岁组检出异常者551人,40~64岁组检出异常者775人,≥65岁组检出异常者1147人。其中屈光不正、白内障、黄斑病变、白内障术后、病理性近视眼底改变、翼状胬肉、倒睫、视网膜动脉硬化、杯盘比异常在<40岁年龄组、40~64岁年龄组及≥65岁年龄3组间检出率差异均有统计学意义(χ2=100.24、1037.23、507.61、232.50、14.46、54.92、21.48、84.24、17.73,P均<0.05),但结膜炎在3个年龄组之间比较差异无统计学意义(χ2=0.58,P>0.05)。OCT(12.60%)对黄斑病变的检出率高于直接检眼镜(9.41%)(χ2=36.357,P<0.05),对黄斑病变中黄斑前膜、黄斑变性、病理性近视视网膜脉络膜病变和黄斑劈裂OCT检查的检出率高于直接检眼镜,差异具有统计学意义(χ2=10.065、4.932、19.836、12.010,P均<0.05)。结论中小学教师不同年龄段眼部疾病谱分布存在差异,可根据该特点制定健康宣教和眼部体检,有利于眼病的早预防和早治疗。OCT对黄斑部疾病的体检筛查有重要应用价值。     

光学相干断层扫描仪能量校准分析研究

目的:分析光学相干断层扫描(OCT)技术设备原理建立能量检测方法,并借助Newport能量表校准相干光能量,解决扫描信号质量低的问题。方法:采用Newport能量表检测超发光二极管(SLD)光源能量,用以解决SLD光源能量不足和光谱仪的光功率低导致的OCT扫描信号质量低问题,对于能量不足的问题采用调整光源电流值,以使相干光能量在正常范围内,通过清洁参考镜光路后提高光功率数值。结果:校准SLD光源前能量为670μW,校准后能量为738μW,清洁参考镜光路后光谱仪的总光功率(TOP)由之前的0.7μW提高至0.9μW,血流报告的扫描信号质量指数(SQ)值从6提高至9。结论:通过扫描质量指数的提升,可提高视网膜扫描断层图像的清晰度和血流报告的SQ值,便于临床对眼内疾病的诊治。     

反滤波技术在提高OCT图像分辨率中的应用

光学相干断层扫描技术（OCT）可对活体组织进行高分辨率的成像，为临床提供诊断依据，但是这种技术受到目前使用光源的局限性，图像的分辨率受到了限制．本文利用倒频谱分析的方法对OCT图像进行反滤波处理，提高了OCT图像的分辨率，达到了图像增强的效果。     

曲安奈德2 种给药方式治疗视网膜静脉阻塞继发黄斑水肿对比研究

目的探讨曲安奈德2种给药方式对视网膜静脉阻塞继发黄斑水肿（RVO—ME）的治疗作用对比研究。方法回顾性分析黑龙江省医院2011—2012年在黑龙江省医院检查确诊并治疗RVO—ME患者72例72眼纳入研究,其中,男39例39眼,女33例33眼,年龄40～71岁。治疗前及治疗后1周,1、3、6个月进行BCVA、非接触眼压、裂隙灯、间接眼底镜检查,OCT检查测量黄斑厚度。结果玻璃体腔注射组治疗前后差异有统计学意义（P〈0．05）;后Tenon下注射组治疗前后差异有统计学意义（P〈0．05）。2组治疗结果差异无统计学意义（P〉0．05）。结论曲安奈德2种给药方式治疗RVO—ME均有疗效,疗效及安全性差异不大。     

光学相干断层成像技术及其在冠心病诊疗中的应用

阐述了光学相干断层成像技术的基本光学原理,结合系统结构框图介绍了仪器成像机理。与血管内超声等技术手段相比,OCT具有抑制散射光、分辨高、灵敏度好等特点,因此在冠心病诊疗中具有重要的应用价值。     

Swept Source OCT dans le suivi d’une effusion uvéale posttrabéculectomie chez une patiente nanophtalme

Uveal effusion syndrome describes serous detachments of the choroid and ciliary body with exudative retinal detachment. It is a complication following glaucoma filtering surgeries such as trabeculectomy especially in nanophthalmic eyes.We report a rare case of a 42-year-old-woman, with nanophtalmos, who developed posterior serous retinal detachment and uveal effusions after trabeculectomy for chronic angle closure glaucoma.The patient was put on oral steroids with good clinical outcome. Anterior Segment OCT allowed monitoring of iridocorneal angle and anterior chamber depth, Swept Source OCT was useful for monitoring retinal reattachment and choroidal thickness.     

Clinical, pathological and photochemical studies of laser injury of the retina

Nineteen cases of acute accidental laser injury of the human retina and two groups of laser workers with chronic retinal damage were reviewed. Most acute cases had macular injury and vision impairment; the chronic cases usually suffered from nonspecific eye complaints. Pathological and photochemical studies of laser injury to rabbit retina were also made following exposure to a 0.49-W Ar laser. The retinal pigment epithelial cells and photoreceptors were mildly damaged in the laser spot center, but the Bruch's membrane was still intact. Malondialdehyde (MDA), the main degradation product of lipid peroxidation of the retina, was assessed with fluorescence spectrophotometry. The level of MDA in the injured retina was significantly higher than that in control eyes, suggesting that thermal levels of Ar laser exposure can yield evidence of photochemical light damage mechanisms.     

Aspects of outcome and therapy of edematous branch retinal vein occlusion

The main cause of oedematous branch retinal vein occlusion (BRVO) vision loss is macular oedema persistence. We studied 18 patients having oedematous branch retinal vein occlusion. An ophthalmologic exam completed with angiography and etiologic assessment were performed. Argon Laser macular grid photocoagulation was performed in 11 eyes where macular oedema had persisted for over 3 months with visual acuity under 5/10. In 45% of cases, occlusion interests superotemporal vein. Atherosclerosis risk factors are found in 88% of cases. The course was spontaneously favourable in 39% of cases. Improvement of visual acuity was obtained in 36% of cases treated with laser photocoagulation. Oedematous branch retinal vein occlusion outcome is variable; it can be favourable if veino-veinous anastomosis develops rapidly, or unfavourable with macular edema persistence and decreased visual acuity. In the later case, grid macular phototcoagulation should be performed leading to macular edema regression. So, macular edema secondary to branch retinal vein occlusion can disappear spontaneously and needs laser treatment only if it persists.     

The Reflexes of the Fundus Oculi: (Section of Ophthalmology)

The fundus reflexes reveal, in a manner not yet completely understood, the texture and contour of the reflecting surfaces and the condition of the underlying tissues. In this way they may play an important part in the biomicroscopy of the eye.The physiological reflexes are seen at their best in the eyes of young subjects, in well-pigmented eyes, with undilated pupils and with emmetropic refraction. Their absence during the first two decades, or their presence after the forties, their occurrence in one eye only, their appearance, disappearance or change of character should suggest the possibility of some pathological state.The investigation and interpretation of the reflexes are notably assisted by comparing the appearances seen with long and short wave lights such as those of the sodium and mercury vapour lamps, in addition to the usual ophthalmoscopic lights. Most of the surface reflexes disappear in the light of the sodium lamp, sometimes revealing important changes in the deeper layers of the retina and choroid.The physiological reflexes, chiefly formed on the surface of the internal limiting membrane, take the forms of the familiar watered silk or patchy reflexes, the peri-macular halo, the fan reflex in the macular depression and the reflex from the foveal pit. The watered silk or patchy reflexes often show a delicate striation which follows the pattern of the nerve-fibre layer, or there may be a granular or criss-cross texture. Reflexes which entirely lack these indications of “texture” should be considered as possibly pathological. This applies to the “beaten metal” reflexes and to those formed on the so-called hyaloid membrane.The occurrence of physiological reflexes in linear form is doubtful, and the only admittedly physiological punctate reflexes are the so-called Gunn''s dots.Surface reflexes which are broken up into small points or flakes are pathological, and are most frequently seen in the central area of the fundus in cases of pigmentary degeneration of the retina or after the subsidence of severe retinitis or retino-choroiditis.A mirror reflex from the layer of pigmented epithelium or from the external limiting membrane is sometimes recognizable in normal eyes, especially in the brunette fundus. In such, it forms the background to a striking picture of the fine circumfoveal vessels.Pathological reflexes from the level of the pigmented epithelium or of the external limiting membrane are also observed, and these often present a granular, frosted or crystalline appearance. They may indicate a senile change, or result from trauma or from retino-choroidal degeneraion. Somewhat similar reflexes may sometimes be present as small frosted patches anterior to the retinal vessels.Linear sinuous, whether appearing in annular form, as straight needles, as broader single sinuous lines, as the tapering, branched double reflexes of Vogt, or in association with traction or pressure folds, in the retina, are probably always pathological.By the use of selected light of long and short wave lengths, it can be shown that intraretinal or true retinal folds may exist with or without the surface reflexes which indicate a corresponding folding of the internal limiting membrane. On the other hand, superficial linear reflexes of various types may occur without evidence of retinal folding.Annular reflexes usually accompany a rounded elevation of the retina due to tumour, hæmorrhage or exudate, but may indicate the presence of rounded depressions; traction folds occur where there is choroido-retinal scarring, or in association with macular hole or cystic degeneraion at the macula; pressure folds in cases of orbital cyst, abscess or neoplasm; and the other linear reflexes in association with papillo-retinal œdema, for example, in retrobulbar neuritis, in hypertensive neuro-retinitis, in contusio bulbi and in anterior uveitis.Punctate reflexes, other than Gunn''s dots, are also pathological. They may occur as one variety of “fragmented” surface reflexes, or as evidence of the presence of some highly refractile substance, such as cholesterin or calcium carbonate, in a retinal exudate or other lesion.It is characteristic of the pathological reflexes that they come and go and change their character according to the progress of the pathological condition. The linear reflexes in particular may change from one from to another, and may be finally transformed into surface reflexes of physiological character.     

傅立叶光学相干断层扫描检测眼房角巩膜突可见性分析

目的探讨傅立叶光学相干断层扫描仪CAM模块房角测量图像中巩膜突可见性及其影响因素。方法连续选择本院眼科门诊40岁及以上患者，所有受试者均接受眼科常规项目检查，房角均分别接受RTvueOCT（Optovue Inc，USA）CAM模块和房角镜检查。分析OCT图像中巩膜突的可见性及其影响因素。结果受试者共98例（98眼），年龄（63．3±10．5）岁，其中女性62例（63．3％）。在392个OCT房角象限中，286个（73．0％）象限的巩膜突可见，在象限之间、局部球结膜是否增厚之间的巩膜突可见率差异有统计学意义（P〈0．叭）。Logistic多元逐步回归分析发现，巩膜突可见性与性别、年龄、房角镜分级均无关（P〉0．05），与局部球结膜增厚（OR：0．113，P〈0．01）、象限（上方与颞侧OR=0．210，下方与颞侧OR=0．340，P〈0．01）有关，其中上、下象限与颞侧相比存在差异（OR=0．210、0．340，P〈0．01）。巩膜突在不可见情况下，仍有80．2％的象限可分辨出房角状态。结论傅里叶OCT作为一项房角检查方法具有较好的可行性，可为判断闭角型青光眼的发病机制提供有用信息。     

叶黄素对视网膜光损伤的保护作用

叶黄素为类胡萝卜素之一,在人体内不能转化为维生素A。人体自身不能合成叶黄素,需要从食物中摄取。叶黄素和玉米黄质共同构成视网膜黄斑色素,是黄斑区唯一存在的两种类胡萝卜色素,能降低视网膜光损伤的程度。叶黄素对视网膜的保护机制主要为:(1)蓝光过滤器的作用,叶黄素对光损伤作用最大的蓝光具有很强的吸收作用;(2)抗氧化作用;叶黄素可以灭活单线态氧和捕获活性氧自由基。