应用OCULUS角膜图诊断早期圆锥角膜的临床探讨

目的 研究0CULUS角膜地形图对早期圆锥角膜的诊断价值。方法 对拟行LASIK手术矫正近视散光患者238人，476眼，使用附有圆锥角膜诊断和表面像差分析程序的0CULUS角膜地形图进行早期圆锥角膜（Keratoconus，KC）诊断，讨论其诊断价值。结果 双眼中任一眼KC判定1级则怀疑双眼早期圆锥角膜，为KC判定阳性组共17人34眼，双眼KC判定阴性组共221人442眼，分为两组进行比较。KC判定正常患者和KC判定1级的近视患者角膜地形图角膜K值、△K，I-S，ABR分别为：（42．70±1．61）D，（0．47±0．34）D，（0．95±0．58）D，0．02±0．50；（43．60±1．76）D，（0．52±0．78）D，（1．37±0．75）D，1．20±0．10。两组角膜中央K值和△K比较P〉0．05，无统计学意义，I-S和ABR比较P〈0．05，有统计学意义。结论 附有圆锥角膜诊断程序和角膜前表面高阶像差测量分析的角膜地形图能更早期发现圆锥角膜改变，且操作简单快速准确，临床运用方便。     

圆锥角膜患者角膜地形图量化参数分析

目的 对圆锥角膜(KC)患者双眼的角膜地形图进行分析,对各量化参数进行特点评估.方法 临床病例研究.对2008年1月至2010年3月在天津医科大学眼科中心就诊符合诊断标准的KC患者63例(108只眼),使用Obscan Ⅱ角膜地形图仪检测双眼角膜,统计分析获得的数量指标,并与作为正常对照眼的64例中高度近视患者(64只眼)进行比较分析.结果 临床期KC组的最大角膜曲率值与最高角膜后表面高度、角膜最薄厚度、3 mm区域不规则值、5 mm区域不规则值差异有统计学意义(P＜0.01).与正常对照组相比,临床期KC眼和亚临床期KC眼均具有较高后表面最大高度值、3 mm不规则值和5 mm不规则值及较低的角膜厚度.临床期KC组、亚临床期KC组及正常组角膜最薄点到角膜中心的平均距离分别为(0.76±0.42) mm、(0.66±0.38) mm和(0.61±0.29) mm.临床期KC组和亚临床期KC组角膜最薄点位置多数在颞下方,而正常组角膜最薄点位置多数位于1 mm圆环区域内.结论 Obscan Ⅱ角膜地形图仪可全面了解角膜前后表面形态,通过分析其量化参数指标,能够更早诊断圆锥角膜.     

角膜地形图分析在圆锥角膜早期诊断中的重要作用

目的　评价角膜地形图分析在圆锥角膜早期诊断中的重要作用。方法　对矫正视力较为理想 ,裂隙灯显微镜及角膜曲率计检查均无阳性发现的 2 0例 (36只眼 )患者 ,利用计算机辅助角膜地形检测仪 (eyesys2 0 0 0 ,美国产 )对角膜影像的参数进行分析 ,并分别于 3个月、6个月、1年进行随访检测明确诊断。结果　早期圆锥角膜患者的 SRI、SAI、角膜中央的屈光力、I- S值、单眼病例两眼角膜中央屈光力的差值、Sim K值及 Sim K的差值、角膜屈光力的变化范围等均增高 ,有助于诊断早期圆锥角膜 ,特别是角膜最大屈光力的位置、角膜屈光力的变化范围对诊断早期圆锥角膜非常敏感。根据文献及笔者临床实践认为以下四个指标更有利于圆锥角膜患者的早期诊断。(1)角膜中央屈光力 >4 6 .0 0 D;(2 )同一病例两眼角膜中央屈光力的差值 >1.0 0 D;(3) I- S值 >2 .0 0 D;(4)最大一环与最小一环屈光力的差值≥ 4 .5 0 D。其中有两项或两项以上发现异常 ,应定期随访 ,如有进行性发展即可确诊圆锥角膜。结论　提示角膜地形图检测是圆锥角膜早期诊断中具有高度敏感性的、可靠的定量分析方法 ,证实了角膜地形图检测在圆锥角膜早期诊断中具有重要的作用 ,是目前最有效的早期诊断方法     

傅里叶域光学相干断层扫描仪测量角膜上皮厚度参数鉴别早期圆锥角膜

目的:探讨傅里叶域光学相干断层扫描仪(FD-OCT)测量角膜上皮厚度参数在圆锥角膜早期诊断中的价值。方法:回顾性对照研究。选取2015-01/2020-10于苏州大学附属第一医院就诊的早期圆锥角膜患者55例62眼,选取同期接受近视激光手术治疗的屈光不正患者110例110眼作为对照组。采用FD-OCT测量获得以瞳孔中心7mm直径范围的角膜上皮层厚度参数、以瞳孔中心9mm直径范围25个分区的角膜上皮层平均厚度值及角膜全层平均厚度值,比较各参数值在早期圆锥角膜组及对照组的差异,对有差异的参数分析诊断价值。结果:早期圆锥角膜组Min-e值较对照组显著减小,Std.Dev值、Max-Min-e值、Max-e值较对照组显著增大(均P<0.001)。Std.Dev值、Max-Min-e值对早期圆锥角膜诊断效能较高(AUC=0.937、0.928),Max-e值、Min-e值诊断效能中等(AUC=0.871、0.797)。25个分区角膜上皮厚度分析,早期圆锥角膜组内环颞下区(EIT1)角膜上皮层厚度变薄最明显,诊断效能最高(AUC=0.827)。各区域角膜全层厚度分析,早期圆锥角膜组各个分区的角膜全层平均厚度值较对照组明显变薄,内环颞下区(CIT1)平均厚度值在25个分区中具有较高的诊断效能(AUC=0.903)。结论:角膜上皮层厚度参数Std.Dev值、Max-Min-e值、Max-e值、Min-e值、内环颞下区角膜上皮层平均厚度值以及内环颞下区角膜平均厚度值可用于鉴别早期圆锥角膜。     

使用Pentacam检测亚临床期和早期圆锥角膜患者角膜体积和前房容积

目的:使用Pentacam检测健康、亚临床期和早期圆锥角膜患者角膜体积和前房容积。方法:流行病学研究。共纳入63例屈光手术患者。根据Amsler-Krumeich标准,将患者分为正常、亚临床期和早期三组。收集了包括年龄和性别在内的人口统计信息,并获得了患者的完整病史。所有患者进行完整的视力检查。随后,使用Pentacam测量三组患者的角膜体积和前房容积。结果:对照组角膜体积明显高于亚临床期组和早期组(P<0.05),但两组间前房容积无显著性差异(P>0.05)。结论:测量角膜体积有助于鉴别亚临床期圆锥角膜和早期圆锥角膜与正常眼。亚临床圆锥角膜患者、早期圆锥角膜患者和正常人的前房容积无显著差异。     

角膜密度测定法及其与角膜前、后仰角的相关性

目的：评估在初治圆锥角膜患者中的角膜密度及其与前和后角膜仰角的相关性。

方法：使用Pentacam检测圆锥角膜。角膜密度测量是通过直径12 mm的区域测量, 分为环形同心区域和深度,测量更多的角膜前后仰角。根据地形圆锥角膜分类对圆锥角膜进行分类。

结果：研究包括152例患者\〖72例圆锥角膜患者(46例男性, 26例女性)和 80例健康对照受试者(50例男性, 30例女性)\〗。两组间角膜2 mm中心处和角膜环状2～6 mm直径处角膜密度测量值差异有统计学意义(K=16.40±2.18 GSU, N=15.31±1.25 GSU, P<0.0001)。当不同深度的密度测量值时,前部层呈现最高值,明显高于中央层和后层的值。当测量不同深度密度值时,前层呈现最高值(KC=23.69±3.71 GSU, N=20.91±2.52 GSU, P<0.0001),显著高于中央层和后层值(KC=14.34±1.70 GSU, N=13.61±1.21 GSU, P=0.001; KC=11.40±1.23 GSU, N=12.35±0.88, P=0.002)。各层深度(前、中、后)角膜密度测量值与后角膜高度值的相关性分析显示两者显著相关(分别为r=0.293, r=0.278 和 r=0.294)。角膜光密度测定每层深度和角膜前角抬高之间没有发现类似的相关性(分别为r=-0.211, r=-0.101, r=0.99)。在对照组受试者中,未发现每层深度角膜前/后角膜高度和角膜后向散射的显著相关性。

结论：光密度图显示前圆锥角膜中央区域的光后向散射较高。圆锥角膜患者的角膜光密度值与角膜0～2、6～10、10～12 mm环状区域前、中、后各层角膜高度相关。     

活体共聚焦显微镜检查在角膜营养不良诊断中的应用

活体共聚焦显微镜检查(in vivo confocal microscopy,IVCM)无创、快速,可活体观察眼表组织及细胞结构的生理、病理变化,在感染性角膜炎诊断及治疗评价、干眼病眼表评估、眼表手术治疗效果评估及糖尿病早期筛查等方面均有广泛应用。利用IVCM观察角膜营养不良有助于诊断、监测疾病进展、评价治疗效果及了解其病理生理变化等。     

角膜厚度测量新进展

角膜厚度值在早期主要应用于协助角膜疾病及青光眼的诊断，随着上世纪90年代角膜屈光手术的发展，准确的角膜厚度测量法越来越重要。为了增强手术的精确性，提高术后的视觉质量，更多的新技术已不仅仅局限于单纯测量角膜厚度。Orbscan角膜地形图、Pentacam三维前房分析仪、Precisio角膜地形图等更可形象地展示角膜、前房、晶状体等形态及其准确数据。     

角膜共焦显微镜早期诊断兔高危角膜移植排斥反应的价值

目的:角膜共焦显微镜检查对兔碱烧伤角膜移植排斥反应进行研究,找寻排斥反应早期诊断的客观指标。方法:制作兔角膜碱烧伤模型,36d后行穿透性角膜移植,于角膜移植术后4,9,14,21~28d诊断排斥反应时,角膜共焦显微镜检查角膜。结果:排斥反应时角膜共焦显微镜检查见角膜植片炎性细胞浸润,角膜细胞丢失,新生血管生长。结论:角膜共焦检查有助于早期诊断排斥反应。     

角膜生物力学特性的测量方法研究现状

角膜是人眼的主要屈光介质。作为一种黏弹性生物组织,角膜具有非线弹性、黏弹性和各向异性的复杂生物力学特性。角膜的生物力学特性对维持角膜的正常形态及功能具有重要作用。在许多眼部疾病中,角膜生物力学的改变常常早于临床症状的出现。因此对角膜生物力学特性的定量测量有利于疾病的早期诊断和治疗。目前测量角膜生物力学有多种方法,包括经典的体外实验,已应用于临床的在体测量法和其他的一些具有临床应用潜力的在体测量法。各种方法测量原理不同并有其相应的优缺点。     

Keratoconus: A biomechanical perspective on loss of corneal stiffness

Keratoconus (KC) is progressive disease of corneal thinning, steepening and collagen degradation. Biomechanics of the cornea is maintained by the intricate collagen network, which is responsible for its unique shape and function. With the disruption of this collagen network, the cornea loses its shape and function, resulting in progressive visual degradation. While KC is essentially a stromal disease, there is evidence that the epithelium undergoes significant thinning similar to the stroma. Several topographical approaches have been developed to detect KC early. However, it is now hypothesized that biomechanical destabilization of the cornea may precede topographic evidence of KC. Biomechanics of KC has been investigated only to a limited extent due to lack of in vivo measurement techniques and/or devices. In this review, we focus on recent work performed to characterize the biomechanical characteristics of KC.     

Biomechanical properties of the keratoconic cornea: a review

There has been a recent surge of interest in assessing corneal biomechanical properties due to potential clinical applications, particularly in the early detection of keratoconus (KC). This review discusses the effects of keratoconus on the biomechanical properties of the cornea and the current techniques used to detect these changes both in the laboratory and clinical setting. Specific structural changes occurring in the corneal stroma as part of the disease process can be linked to alterations in the viscous and elastic properties of the cornea in keratoconus. Although there are extensive ex vivo studies using techniques such as extensometry and inflation testing to analyse the biomechanical properties of the normal cornea, few have investigated the keratoconic cornea using the same methods. There are a number of ex vivo studies that confirm the effectiveness of collagen cross‐linking in increasing Young's modulus in healthy corneas. Recently, research has focussed on measuring corneal biomechanical parameters in vivo using two commercially available instruments: the Ocular Response Analyser (ORA) and the CorVis ST (CST). Both instruments analyse the dynamic behaviour of the cornea, when temporarily deformed by an air puff; however, the outputs of these instruments are not directly comparable due to differences in the characteristics of the air puff and output parameters. Studies using these instruments have reported significant differences between keratoconic and healthy corneas; however, neither instrument can currently be used in isolation to reliably diagnose keratoconus. Further research analysing the outputs of these instruments may enhance their diagnostic capabilities.     

感染性角膜病病原学诊断中存在的问题及对策

感染性角膜病是我国角膜病致盲的首位因素,准确的病原学诊断是对其合理治疗的关键.随着认识的提高和各项检验及检查技术的发展,感染性角膜病的病原学诊断水平也在提高,但仍存在诸多科学问题尚待解决.本文就我国感染性角膜病的病原学诊断存在的科学问题进行分析,并提出相应的建设性策略.     

Corneal thickness: measurement and implications

The thickness of the cornea was reported in more than 100-year-old textbooks on physiological optics (Helmholtz, Gullstrand). Physiological interest was revived in the 1950s by David Maurice, and over the next 50 years, this 'simple' biological parameter has been studied extensively. Several techniques for its measurement have been described and physiological and clinical significance have been studied. In this review, the different methods and techniques of measurement are briefly presented (optical, ultrasound). While the corneal thickness of many animals are the same over a considerable part of the surface, in the human cornea anterior and posterior curvature are not concentric giving rise to a problem of definition. Based on this the precision and accuracy of determining the central corneal thickness are discussed. Changes in corneal thickness reflects changes in function of the boundary layers, in particular the endothelial barrier. The absolute value of thickness is of importance for the estimation of IOP but also in diagnosis of corneal and systemic disorders. Finally it is discussed to what extent the thickness is a biometric parameter of significance, e.g. in the progression of myopia or in the development of retinal detachment.     

Congenital corneal anesthesia

Congenital corneal anesthesia is a rare clinical entity that poses a diagnostic dilemma, particularly in the pediatric age group. The sensory deficit may be confined to the cornea, or extend to other divisions of the trigeminal nerve. The sensory deficit may occur as an isolated abnormality, as part of a complex neurological syndrome, or it may occur in association with multiple somatic abnormalities and congenital insensitivity to pain. This condition usually presents between the ages of 8 to 12 months. Poor vision, photophobia, conjunctival injection, and corneal ulceration in the absence of pain and distress in a child should alert the clinician to the possibility of anesthetic cornea. In the early stages of presentation, punctuate keratopathy is the main feature, which may progress to non-healing persistent corneal epithelial defects. This stage may progress to acute corneal lysis and perforation. In most patients, conservative approaches such as copious lubrication, prevention of self-harm and cautious use of bandage contact lenses are effective in preventing progressive corneal damage. Tarsorrhapy is effective in promoting epithelial healing and permanent lateral tarsorraphy may prevent further development of epithelial defects. Amniotic membrane graft may be considered in order to improve epithelial healing. Corneal grafts carry a poor prognosis. Accurate initial diagnosis, evaluation, and proper management are paramount to prevent visual loss due to long-term complications of corneal anesthesia. This review of the literature outlines the problems and approaches in diagnosis, evaluation, and management of this rare condition.     

角膜层间积液综合征

角膜层间积液综合征是指角膜基质层间出现间隙,房水渗入其间,使实质层分离,导致视力严重下降的一种疾病.其发病原因为板层屈光手术后任何原因引起的眼压增高或角膜内皮功能障碍,引发角膜水肿,出现层间积液.由于此病较为罕见,临床上角膜层间混浊近似弥漫性板层角膜炎,角膜中央部眼压隐匿性增高,极易误诊漏诊.通过眼前节相干光断层扫描检查,可明确诊断.积极寻找原发病因、早期诊断、及时准确治疗,预后一般良好.     

角膜交联术新进展与临床运用

紫外光核黄素角膜交联术(corneal collagen cross-linking,CCL)是一种二十一世纪初应用于临床的最新的角膜成形技术。以核黄素作为光敏剂应用370nm紫外线对角膜进行局部照射,刺激胶原纤维交联,增加角膜硬度。该技术已经在临床崭露头角,有望成为人们比较熟悉的角膜成型技术如传导性角膜成形术和角膜基质环植入术的辅助治疗手段。这些被称为角膜成形学的治疗或手术技术,可望开辟一个新的领域,治疗以往无法治疗的某些角膜疾病。利用CCL,眼科医生可重塑角膜结构,而不需使用如穿透性角膜移植术或板层角膜移植术等创伤性技术。用这种方法代替角膜基质环植入术,或与之相结合,可显著提高圆锥角膜的治疗效果。经过几年的苦心研究,CCL的技术方法得到了改进,治疗范围也有所扩大。不仅用来治疗进展性圆锥角膜,同时也为难治性角膜溃疡、角膜变性、术后角膜扩张病等角膜疾病的治疗带来希望。     

RANTES与SPARC基因在大鼠角膜移植排斥反应中的表达

目的：动态检测激活正常T细胞表达和分泌的调节物（regulated on activation nomal T expressed and secreted,RANTES)和酸性富含胱氨酸分泌型蛋白（secreted protein,acidic and rich in cysteine,SPARC)在异体角膜移植排斥反应中的表达，为角膜移植排斥反应的早期诊断提供依据。方法：首先建立大鼠异体角膜移植动物模型，并设同体角膜移植，角膜碱烧伤模型为对照组，在不同时间段提取各组角膜上皮细胞总RNA。分别进行逆转录－聚合酶链反应（RT－PCR）扩增，电泳，半定量检测RANTES和SPARCmRNA的表达水平，然后酶切验证表达结果。结果：（1）正常角膜上皮细胞未见RANTES基因表达，可见SPARC基因的低表达；（2）异体角膜移植3天后各时间点均见排斥眼RANTES基因的高表达，同体移植及碱烧伤后未见表达。（3）SPARC在角膜移植及碱烧伤后均见较高水平表达，且与正常细胞表达有显著差异；（4）用RT－PCR方法检测基因变化诊断排斥反应早于裂隙灯检查结果。结论：大鼠角膜上皮RANTESmRNA表达上调与角膜移植排斥反应特异性相关。同时，SPARC在角膜移植排斥反应，碱烧伤和创伤过程中具有高水平表达，依时间顺序，RANTES和SPARC早期高表达早于临床观察的排斥反应至少一周，由此，选择性对细胞因子mRNA扩增，是早期诊断角膜移植排斥反应的有效方法。     

角膜异物812例分析

目的分析角膜异物的原因及后果,提出防治方法的建议。方法对812例（851眼）角膜异物病因及诊治结果进行统计分析,找出角膜异物伤的主要原因及分析其对视力、角膜的影响。结果角膜异物以铁质金属为主,多由于工作中劳动保护不当所致,部分留有视力及角膜损害。结论角膜异物是非常常见的眼外伤,对视力及角膜会造成一定的损害,应积极预防,及时、合理治疗。     

Determination of corneal volume from anterior topography and topographic pachymetry: application to healthy and keratoconic eyes

Purpose: To describe a method to measure corneal volume from topography and pachymetry, and test its clinical use on a sample of healthy human subjects and a case of circumscribed posterior keratoconus. Methods: Corneal curvature (PCT 200^® corneal topography system; Optopol Technology SA, Zawiercie, Poland) and ultrasonic topographic pachometry on 25 points (Ophthasonic^® A‐Scan/Pachometer III; Teknar Inc., St Louis, MO, USA) were measured on each of 12 young healthy corneas and one cornea suffering from circumscribed posterior keratoconus. Topography and pachymetry data were used to calculate the coordinates for the corresponding points on the posterior surface of the cornea. TableCurve 3D software (Systat Software Inc., Chicago, IL, USA) was used to fit a surface to those points measured. Integration of the surface fitted to the data points, corresponding to the anterior and posterior corneal surfaces, was used to calculate the volume underneath each of them. Subtraction of volumes underneath anterior and posterior surfaces, taking into account an axial offset equal to the central corneal thickness, rendered corneal volume for the central 6 mm of the cornea. Results: Central corneal thickness ranged from 520 to 630 μm for the healthy corneas. Corneal volumes for this sample analyzed averaged 18.66 ± 1.15 mm³ (range 17.25–20.53 mm³). For the posterior keratoconic cornea, the affected area was located at about 1.5–2 mm from the corneal center on the 135° hemimeridian of the right eye, observed through topographic pachymetry. Calculated corneal volume for the central 6 mm was 16.072 mm³, noticeably lower than those found in the sample without pathology, but within the range for corneas presenting with keratoconus. Conclusions: Corneal volume is a useful parameter for characterising dystrophic corneas and can aid in the detection of rare anomalies which are hardly detected with corneal topography and/or central corneal thickness evaluation. A potentially useful measure of corneal volume can be calculated from anterior corneal topography and topographic pachymetry data. Values obtained are in good agreement with previous studies using corneal tomography techniques. The methodology has been shown to have potential for retrospective analysis of data, or where no access is available to tomographical techniques.