中国人正常角膜的共焦显微镜检查

摘要目的探讨正常人共焦显微镜下角膜各层细胞的活体细胞形态学特征及密度.方法对28例(年龄36.6士14.5岁,范围19～68岁)41眼(男14眼,女27眼)正常人中央部角膜进行活体共焦显微镜检查,描述角膜各层结构的图象特点,并分析角膜各层细胞的密度与年龄的相关性.结果上皮表层细胞排列疏松,边界清楚,核反光较强;基底层细胞排列紧密,胞质和核反光弱,偶尔可见点状细胞核,细胞平均密度为5724.41士562.5个/mm2.Bowman's膜为无一定形状的膜状物,仅可分辨的结构是上皮下的念珠状神经纤维.基质层中可见相对较暗的背景下明亮的角膜细胞核.前基质内有放射状分布的神经纤维.前基质层角膜细胞平均密度为1099.10士164.90个/mm     

三种实验动物角膜活体共焦显微镜检测的比较解剖学研究

背景 海德堡视网膜厚度分析仪和角膜模块的结合实现了对眼表活体组织结构的非侵入性检查,利用共焦显微镜对常用实验动物角膜结构进行比较研究可为相关研究提供依据.目的 利用活体共焦显微镜比较新西兰大白兔、Lewis大鼠、Swiss小鼠的角膜结构,建立实验动物角膜的活体组织图像资料,为共焦显微镜的实验研究提供依据.方法 利用海德堡视网膜厚度分析仪(HRT-Ⅱ)的Rostock角膜模块对新西兰大白兔、Lewis大鼠、Swiss小鼠的角膜进行活体分析,角膜的每一层各采集20张共焦显微镜图片,比较分析实验动物角膜各层的形态学特点及角膜内皮细胞密度.结果 共焦显微镜下3种实验动物角膜表层上皮细胞表现为高反光或低反光的多形细胞,基底上皮细胞表现为暗的细胞质,细胞核不可见,细胞间排列紧密、规则；前弹力层均表现为含有丰富上皮下神经丛的无定形物质.兔角膜基质层在黑色背景中散布着高反光物质,即为角膜基质细胞核,后基质层细胞密度高于前基质层；大鼠和小鼠的角膜基质层仅观察到大量反光的星形结构,无明显的细胞核.3种实验动物的角膜内皮细胞形态相似,均表现为高反光的胞体,边界较暗且细胞排列成蜂窝状.新西兰兔前基质角膜细胞密度中位数为387.5个/mm2,后基质角膜细胞密度中位数为223.5个/mm2,明显少于前基质的细胞密度(U=0.000,P=0.000)；新西兰兔、Lewis大鼠、Swiss小鼠角膜内皮细胞密度中位数分别为2192.5、1936.0、1565.0个/mm2,总体差异有统计学意义(H=49.940,P=0.000),兔角膜内皮细胞密度明显高于大鼠和小鼠,差异均有统计学意义(x2=0.000,P=0.000；x2=0.000,P=0.000),大鼠和小鼠的角膜内皮细胞密度差异亦有统计学意义(x2=0.000,P=0.000).结论 共焦显微镜下新西兰大白兔、Lewis大鼠、Swiss小鼠角膜各层的细胞形态相似,但内皮细胞密度和基质细胞形态之间存在明显差异.HRT-Ⅱ的Rostock角膜模块可为动物实验提供角膜各层次的高分辨率图像.     

板层角膜移植术后全层角膜组织改变的共焦显微镜观察

目的研究活体扳层角膜移植术后角膜各层组织的共焦显微镜(confocal microscopy)形态学改变，方法应用Confoscan 2.0共焦显微镜对板层角膜移植术后3月～3年，角膜植片稳定的患者共17例17眼，进行扫描检查，记录与分析各层角膜图像。结果共焦显微镜上能够清楚地观察到稳定角膜的上皮细胞、基底层细胞、前弹力层，它们同正常角膜的相应细胞在图像上没有显著差别。但植片与植床的基质细胞在共焦显微镜图像上有着明显的差异。板层角膜移植术后稳定角膜植片的基质细胞，细胞核较小呈中等反光，排列较植床的基质细胞紊乱。而角膜植床的基质细胞，细胞核较大也呈中等反光，排列较植片的基质细胞稍整齐，结论1、Confoscan 2.0共焦显微镜可活体检查，板层角膜移植术后角膜组织结构和细胞的病理改变。2、板层角膜移植术后可成功的重建眼表。3、活体板层角膜移植术后稳定角膜上有自体角膜基质细胞与异体的角膜基质细胞同时共存，角膜内发细胞的形态结构正常。4、角膜板层间的不平滑与植片基质细胞结构紊乱可能是导致板层角膜移植术后视力不佳的重要原因。     

角膜内皮炎共焦显微镜形态学分析

目的:观察角膜内皮炎的共焦显微镜下形态学特征。方法:应用Confoscan 4.0共焦显微镜对24例24眼角膜内皮炎患者的角膜进行扫描检查,记录并分析各层角膜图像。结果:所有患者前部基质混浊,角膜深基质层可见基质细胞排列紊乱及条索状高反光结构,深基质层中还可见低反光带为后弹力层皱褶,角膜内皮细胞前可见斑片状大小不等的高反光结构,病变区角膜内皮细胞水肿、变性呈无结构暗区,内皮细胞呈多形性改变。4眼角膜上皮细胞边界不清,排列疏松,细胞较大,细胞核呈高反光结构,其中可见泡状暗区。结论:共焦显微镜可活体检查角膜内皮炎患者角膜组织各层结构,起到类似病理组织切片的作用;角膜内皮炎以深基质层及内皮细胞层损害为特征;共焦显微镜检查对角膜内皮炎具有一定的参考价值。     

颗粒状角膜营养不良活体共焦显微镜形态学研究

目的研究颗粒状角膜营养不良角膜各层组织的共焦显微镜形态改变。方法应用Confoscan2.0共焦显微镜对13例(26眼)颗粒状角膜营养不良患者的角膜进行扫描检查,记录与分析各层角膜图像。结果所有患眼前基质细胞及16/26眼后基质细胞结构不清,排列紊乱,并可见短棒状多形性强反光;6/26眼前弹力层不规则并增厚,神经纤维密度明显下降;6/26眼角膜上皮基底细胞层可见不定型的强反光;2/26眼角膜上皮细胞边界不清,排列呈疏松的蜂窝状,并出现不透明的强反光;所有患者角膜内皮细胞形态基本正常。视力0.3以下的患眼角膜上皮细胞层、上皮基底细胞层、前弹力层、后基质层发生形态异常的比例高于0.3以上的患眼(P<0.05)。结论1.共焦显微镜可活体检查颗粒状角膜营养不良角膜组织各层结构,起到类似病理组织切片的作用。2.前基质层形态异常可能是颗粒状角膜营养不良最基本的共焦显微镜形态特征,病情越重,前基质层以外的其它层次发生形态异常的可能性越大,但内皮细胞层一般不受累。3.共焦显微镜检查对颗粒状角膜营养不良手术方式的选择具有一定的参考价值。     

正常角膜基质细胞密度和角膜厚度的研究

目的观察Confoscan 2.0共焦显微镜下正常活体角膜影像表现,测量基质细胞密度与各层厚度.方法检查34例(48眼)正常人.记录图像,并计算基质细胞密度和各层厚度.结果基质细胞密度从前到后逐渐降低,前基质比后基质细胞密度明显增高(t=-9.016,P=0.000),Bowman膜下密度最高,为(1113.2±227)个/mm2.全基质细胞密度为(806.5±57)个/mm2.角膜中央厚度为(568.3±53.8)μm,基质层为(465.5±60.2)μm,上皮层为(58.5±20.4)μm.各层厚度均与全基质细胞密度无显著相关性(P＞0.05).结论Confoscan 2.0共焦显微镜能检测角膜基质细胞密度和各层厚度.     

应用共焦显微镜观察Fuch角膜内皮营养不良患者的病变形态学特征

目的探讨应用共焦显微镜观察我国Fuch角膜内皮营养不良患者角膜各层的活体形态学特征。方法对19例(38只眼)Fuch角膜内皮营养不良患者的中央部角膜进行活体共焦显微镜检查,分为有症状组(19只眼)和无症状组(19只眼),并选取30只眼作为正常对照组,应用NAVIS软件测量、分析角膜各层组织细胞形态和密度,以及滴状赘疣和角膜神经的直径。结果 (1)有症状组:19只眼的角膜内皮层均见到滴状赘疣,直径20-60 μm,内皮细胞密度与正常对照组比较差异有显著意义(t=18.74,P<0.01);9只眼后弹力膜增厚;14只眼角膜后基质层有长条形暗区结构;19只眼角膜基质反光普遍增强;17只眼Bowman膜有局灶性高反光区域;19只眼基底上皮细胞形态大致正常;10只眼显示正常的角膜神经结构;后、前基质细胞密度,与正常对照组比较差异无显著意义(t=0.854、1.173,P=0.38、0.24)。(2)无症状组:19只眼的角膜内皮层均见到滴状赘疣,数目较有症状组者少,直径15-40μm;内皮细胞密度,与正常对照组比较,差异无显著意义(t=1.998,P=0.053);角膜其余各层未见异常。有症状组与无症状组的内皮细胞密度计数比较,差异有非常显著意义(t=8.352,P<0.01)。结论活体共焦显微镜检查有助于Fuch角膜内皮营养不良患者的诊断,特别适用于角膜水肿、角膜内皮镜无法成像的患者。(     

激光共焦显微镜对正常人眼角膜缘和中央角膜的观察

目的应用激光共焦显微镜对正常人眼角膜缘和中央角膜的组织结构与细胞形态的观察和分析。方法选择15名正常人的28只眼接受常规裂隙灯显微镜和检眼镜检查后,作为正常健康眼入选本研究。使用激光共焦显微镜对其上、下方角膜缘和角膜中央区进行检查,各层角膜图像均被记录,观察组织结构和细胞形态,对细胞密度进行计数并分析。结果所获角膜缘和角膜中央各层平面图像(x,y轴)及纵向断层图像(z轴)均非常清晰,同时获取动态录像。上、下方角膜缘均呈现Vogt栅栏状结构,并动态观察到血细胞在血管内的流动。表层上皮细胞排列非常疏松,边界明亮,胞体发暗,上方和下方角膜缘表层上皮细胞平均密度分别为(812±297)个/mm2和(785±263)个/mm2,二者比较差异无统计学意义(P>0.05)。上皮下可见明亮的Langerhans细胞,形态不规则,呈树枝状,上方和下方角膜缘Langerhans细胞平均密度分别为(288±102)个/mm2和(254±127)/mm2,二者比较差异无统计学意义(P>0.05)。角膜中央表层上皮细胞排列疏松,边界发亮,胞体发暗,细胞平均密度为(1098±315)个/mm2,多于上方和下方角膜缘(P<0.05)。基底上皮细胞排列紧密。上皮下和前基质层可见反光强烈的神经纤维丛,旁边偶见明亮的Langerhans细胞,形态不规则,细胞密度难以计算。浅层的神经纤维细小、弯曲度大、多小分支,深层的神经纤维粗大、弯曲度小、少见分支。基质层暗背景下散在分布细长的基质细胞,边缘欠清,细胞核明亮呈纺锤形。内皮细胞为排列整齐的六边形细胞,胞体发亮,边界发暗。角膜中央全层、基质层、上皮层厚度分别为(543.0±62.9)、(462·0±69.5)、(59.9±11.2)μm。结论激光共焦显微镜不仅可以对角膜进行无创的、实时的、活体的检查,而且与传统的光学共焦显微镜相比,具有高清晰度、确切的深度定位、时间动态观察、纵向断层扫描等优势,更可提供理想的角膜缘图像,对角膜疾病尤其是角膜缘疾病的基础研究与临床诊断将更有价值。     

应用共聚焦显微镜观察正常老年人角膜形态学的特点

目的:探讨正常老年人共焦显微镜下角膜各层组织的活体细胞形态学特征。方法:正常老年人19例22眼中央角膜应用共聚焦显微镜(confocal microscope through focus,CMTF)进行观察,记录上皮翼状细胞层、上皮基底细胞层、前基质层、后基质层、内皮层的细胞密度,选取每人上皮基底细胞层下神经丛和中后基质层神经最清晰图像,并记录此幅图像中神经纤维总长度、神经纤维直径、神经纤维数目和每100μm神经纤维包含的念珠状结构(beads)数目,同时比较不同眼别及不同性别之间上述计量和计数资料之间的差别;观察上皮翼状细胞层、上皮基底细胞层、前基质层、后基质层、内皮层及上皮基底细胞层下神经丛(subbasal epithelial nerve plexus)和中后基质层神经(stromal nerves)的组织形态。结果:上皮翼状细胞层、上皮基底细胞层、前基质层、后基质层、内皮层的细胞密度分别为2150±315,5270±539,859±137,627±184,2529±654个/mm2,上皮基底细胞层下神经丛每幅图像中神经纤维总长度、神经纤维直径和数目、每100μm神经纤维包含的念珠状结构分别为944±176μm,2.3±0.5μm,9.0±1.3条,4.9±1.4;中后基质层神经每幅图像中神经纤维总长度、神经纤维直径和数目、每100μm神经纤维包含的念珠状结构分别为306±138μm,5.6±1.7μm,1.8±1.5条,0.0±0.0。上述计量和计数资料左、右眼和男、女之间无统计学差异。同时观察到排列疏松、细胞间夹杂有无结构暗区的表层上皮细胞层,过度形态的翼状上皮细胞层,呈"斑马皮样"外观的基底细胞层,在角膜中后基质层有4眼(18%)可见到微皱褶(microfolds),在排列规则、多呈六边型的角膜内皮层发现有2眼(9%)出现类似滴状赘疣(pseudoguttata-like)结构。结论:共焦显微镜可以在实时、活体和三维空间从细胞水平对角膜各层结构进行定量和定性分析。     

Sjgren综合征患者的角膜激光共焦显微镜活体观察

目的应用激光共焦显微镜观察Sjgren综合征(SS)患者角膜各层的形态改变。方法应用激光共焦显微镜对15例(30眼)SS患者和15例(30眼)同龄正常对照组的角膜进行检查,获取角膜全层图像,并进行比较、分析。结果与对照组相比,SS组角膜上皮各层细胞密度均明显下降,并出现炎性细胞和树突状细胞浸润。角膜基质细胞呈多突起星状,细胞体积增大,胞核反光减弱,胞质反光增强,浅基质出现炎性细胞浸润。SS组较对照组角膜上皮下神经纤维变细,弯曲度变大,走行方向明显改变,部分神经纤维断裂。结论SS患者不仅角膜上皮、浅基质细胞、上皮下神经出现明显改变,且角膜基质细胞形态与角膜免疫状态均出现异常。     

Normal human keratocyte density and corneal thickness measurement by using confocal microscopy in vivo

PURPOSE: To quantify keratocyte density according to stromal region and subject age and to measure the thickness of the normal human cornea and its layers in vivo. METHODS: Seventy normal corneas of 70 subjects were examined by confocal microscopy (contact lens wearers were excluded). Ages of subjects ranged from 12 to 80 years, with 10 subjects per decade. Images were recorded by continuously focusing the optical section through the full-thickness central cornea. Two independent human observers manually identified bright objects (keratocyte nuclei) against a dark background to quantify keratocyte density. This method was validated histologically in three human corneas. Thickness measurements were obtained by plotting mean reflected light intensity in images against corneal depth, and calculating distances between intensity peaks that corresponded to corneal layers. RESULTS: Full-thickness central keratocyte density was 20,522 +/- 2,981 cells/mm(3) (mean +/- SD, n = 69). The number of keratocytes in a full-thickness column of central stroma, which had a cross-sectional area of 1 mm(2), was 9624 +/- 1385 cells. Keratocyte density was highest in the anterior 10% of the stroma. Full-thickness keratocyte density was correlated with age (r = -0.62, P < 0.001), decreasing 0.45% per year. Central corneal thickness was 563.0 +/- 31.1 microm (mean +/- SD) and central epithelial thickness was 48.6 +/- 5.1 microm. CONCLUSIONS: This is the first study to quantify regional keratocyte density comprehensively in vivo across a broad age range of normal human subjects. The method was acceptable to both subject and observer, and may prove useful for quantifying keratocyte density in patients with corneal disorders or after corneal surgery.     

Confocal microscopy in vivo in corneas of long-term contact lens wearers

PURPOSE: To compare keratocyte density, stromal backscatter, epithelial thickness, and corneal sensitivity between corneas of long-term contact lens wearers and those of non-contact lens wearers. METHODS: Twenty corneas of 20 daily contact lens wearers (>10 years' duration) and 20 corneas of 20 age-matched (+/-5 years) control subjects who had never worn contact lenses, were examined by confocal microscopy in vivo. The contact lens wearers removed their lenses 12 to 24 hours before the examination. Full-thickness images were recorded from the central and temporal cornea, and bright objects (keratocyte nuclei) in images were manually counted to calculate keratocyte density. Stromal intensity (backscatter) was measured by calculating the mean grayscale value (corrected for camera and light source variations) from the center of stromal images. Epithelial thickness was determined from the distance between images of the surface epithelium and subbasal nerve plexus. Central corneal sensitivity was measured by Cochet-Bonnet esthesiometry and correlated with the number of nerve fiber bundles in the subbasal nerve plexus. RESULTS: Full-thickness central and temporal keratocyte densities in contact lens wearers were 22,122 +/- 2,676 cells/mm(3) (mean +/- SD) and 20,731 +/- 2,627 cells/mm(3), respectively, and were not significantly different from central and temporal keratocyte densities in control subjects (P = 0.29). The minimum detectable difference in cell density was 11% (2346 cells/mm(3) and 2235 cells/mm(3) in central and temporal stroma, respectively). Temporal epithelial thickness was 46.3 +/- 4.7 microm in contact lens wearers and 50.9 +/- 4.7 microm in control subjects (P = 0.02). Central epithelial thickness and stromal backscatter did not differ between contact lens wearers and control subjects (P > 0.05). Corneal sensitivity was lower in contact lens wearers than it was in control subjects (P = 0.05) and did not correlate with the number of nerve fiber bundles in the subbasal nerve plexus. CONCLUSIONS: Long-term daily contact lens wear and its associated stromal hypoxia and acidosis have no demonstrable effect on keratocyte density. The temporal epithelium is thinner in corneas of long-term contact lens wearers than in control subjects. Decreased corneal sensitivity in contact lens wearers is not accompanied by decreased nerve fiber bundle density.     

Depth and age-dependent distribution of keratocytes in healthy human corneas: a study using scanning-slit confocal microscopy in vivo

PURPOSE: To document keratocyte distribution and changes with age in the cellular network of the human cornea in vivo. SETTING: Department of Ophthalmology, University of Rostock, Rostock, Germany. METHODS: Forty-nine eyes of 31 healthy subjects of various ages were examined with a modified Microphthal scanning-slit confocal microscope (SSCM) (Hund) to document keratocyte distribution in the intact living cornea. Optical sections made by confocal microscopy were recorded on videotape, and the keratocyte density was determined for the total volume of the cornea and for the stromal sublayers. RESULTS: The highest cell density was in the anterior stroma of the cornea immediately posterior to Bowman's membrane (24 320 cells/mm(3) +/- 6740 [SD]), the lowest in the central area (11,610 +/- 4290 cells/mm(3)), and an intermediate density in the posterior stroma immediately adjacent to Descemet's membrane (18,850 +/- 4610 cells/mm(3)). The differences were statistically significant (P <.005). The keratocyte density was significantly lower in the anterior and posterior regions in the group older than 50 years: Cell density at 4% depth was 20,960 +/- 8200 cells/mm(3) and at 96%, 15 520 +/- 4290 cells/mm(3) (P <.05). CONCLUSIONS: In healthy living corneas, the keratocyte density was high in the areas adjacent to Bowman's and Descemet's membranes and was lower in patients older than 50 years than in those younger than 50 years. Further studies are needed to document the rate of change with age and to better understand the role and capacity of aging keratocytes in regenerative processes following corneal diseases or surgical procedures.     

In-vivo slit scanning confocal microscopy of normal corneas in Indian eyes

OBJECTIVE: To study the cellular populations of healthy corneas of Indian eyes using confocal microscopy and to evaluate the correlation with age, gender and laterality. METHODS: The central corneas of 100 eyes of 50 healthy subjects were examined using an in-vivo slit scanning confocal microscope (Confoscan 2). Images were analysed for cell densities of the epithelium, stroma and endothelium. RESULTS: Good quality images enabling analysis of all cell layer populations were obtained in 74 eyes of 43 healthy subjects (22 males and 21 females) with a mean age of 31.89 +/- 13.47 (range 19-71 years). The basal epithelial cell density was 3601.38 +/- 408.19 cells/mm2 (range 3017.3-4231.1 cells/mm2). The mean keratocyte nuclei density in the anterior stroma was 1005.02 +/- 396.86 cells/mm2 (range 571.6-1249.6 cells/mm2) and in the posterior stroma was 654.32 +/- 147.09 cells/mm2 (range 402.6-1049.1 cells/mm2). Posterior keratocyte nuclei density was 30.76% less than the anterior stromal keratocyte nuclei density. The difference in keratocyte nuclei density was statistically significant (P=0.001). The mean endothelial cell density was 2818.1 +/- 361.03 cells/mm2 (range 2118.9-4434 cells/mm2) and the mean endothelial cell area was found to be 385.44 +/- 42.66 mm2 (range 268.9-489.2 mm2). Hexagonal cells formed 22.5-69.4% of the endothelial cell populations (mean 42.04 +/- 11.81%). Mean coefficient of cell size variation was 32.29 +/- 3.06 (range 27.2-39.2). No statistically significant differences were found in cell densities of any corneal layer either between female and male patients or between right and left eyes. Basal epithelial cell density, anterior stromal keratocyte nuclei and posterior stromal keratocyte nuclei density were unaffected by age (r=0.12, 0.07, -0.12 respectively) (P=0.001). There was a statistically significant negative correlation between mean endothelial cell density and increase in age (r=-0.42, P=0.001). Coefficient of cell size variation and age were positively correlated (r=0.73, P=0.001). CONCLUSION: In-vivo slit scanning confocal microscopy is useful for the study of corneal cell populations. Our study provides normative data of these cell populations.     

Keratocyte density in keratoconus. A confocal microscopy study(a)

PURPOSE: To estimate keratocyte density in human corneas with keratoconus by confocal microscopy. DESIGN: Prospective, observational cohort study. METHODS: Twenty-nine unscarred corneas of 19 patients with keratoconus and 29 corneas of 19 controls matched for age (+/-3 years) and contact lens wear were examined by using confocal microscopy. Images were recorded from the full-thickness central cornea. A masked observer manually counted bright objects (keratocyte nuclei) in images without motion blur. Cell densities in anteroposterior stromal layers of keratoconus corneas were compared with densities in corresponding layers of control corneas. RESULTS: In keratoconus patients, age 40 +/- 15 years (mean +/- standard deviation), keratocyte density was 19% lower in those who wore contact lenses (16,894 +/- 4032 cell/mm(3), n = 12) than in those who did not wear contact lenses (20,827 +/- 4934 cell/mm(3), n = 17, P =.03). In control patients, age 39 +/- 16 years, there was no difference in keratocyte density between those who wore contact lenses (n = 12) and those who did not wear contact lenses (n = 17, P =.80). Among contact lens wearers, keratocyte density was 25% lower in keratoconus corneas (16,894 +/- 4, 032 cell/mm(3), n = 12 [9 = rigid gas-permeable lenses, 3 = soft lenses]) than in control corneas (22,579 +/- 2, 387 cell/mm(3), n = 12 [3 = rigid gas-permeable lenses, 9 = soft lenses], P =.002), the result of cell density being lower in the most anterior keratocyte layer (P =.001) and the layers between 0% to 10% (P <.001), 67% to 90% (P <.001), and 91% to 100% (P <.001) of stromal thickness. Among noncontact lens wearers, there was no difference in cell density between keratoconus and controls (P =.41). CONCLUSION: Keratocyte density is decreased in the anterior and posterior stroma of keratoconus patients who wear contact lenses.     

Quantitative analysis of corneal microstructure in keratoconus utilising in vivo confocal microscopy

PURPOSE: To establish and quantify the in vivo confocal microscopic features of moderate to advanced keratoconus. METHODS: Nineteen keratoconus subjects were catergorised using Orbscan-derived corneal apex power and pachymetry as exhibiting moderate (n=7) and advanced (n=12) keratoconus. Control subjects included 23 noncontact lens wearers (Group A) and 15 contact lens wearers (Group B). All subjects underwent Confoscan slit scanning in vivo confocal microscopy. RESULTS: Compared with Group A (4912+/-434 cells/mm(2)), basal epithelial density was significantly lower in both moderate (4592+/-414 cells/mm(2), P<0.05) and advanced keratoconus (4530+/-596 cells/mm(2), P=0.01). In comparison to Group A (761+/-118 cells/mm(2)), anterior stroma keratocyte density was significantly greater in both moderate keratoconus (883+/-111 cells/mm(2), P=0.001) and advanced keratoconus (952+/-122 cells/mm(2), P<0.001). Compared to Group A (504+/-80 cells/mm(2)) posterior stroma keratocyte density was also significantly greater in advanced keratoconus (599+/-97 cells/mm(2), P<0.001) and posterior stromal keratocyte density appeared to increase with increasing severity of keratoconus (P<0.05). However, comparing control Groups A and B, contact lens wear per se, was associated with significantly reduced (P=0.000) keratocyte density in the anterior stroma (609+/-66 cells/mm(2)) and demonstrated a trend (P=0.056) in the posterior stroma (470+/-63 cells/mm(2)). Keratoconic corneas (429+/-72 microm) were significantly thinner than control Groups A (508+/-77 mm) and B (495+/-80 microm). The presence of keratoconus did not affect the endothelial cell density (P=0.54). CONCLUSION: In vivo confocal microscopy can provide insight into the microstructural changes that occur in keratoconus.     

共焦显微镜对近视人群中央角膜组织学改变与年龄相关性的研究

目的探讨共焦显微镜对近视人群中央角膜各层组织的活体观察和分析。方法选择2003年8月-2007年12月天津医科大学眼科中心进行屈光手术术前检查者122例（122眼），其中男54例（54眼），女68例（68眼）；年龄18～80岁，平均（28．54±12．4）岁；等效屈光度数为-0．50～-6．0D。检查并记录各层角膜图像，并对各层细胞形态、细胞密度进行分析。结果角膜全层厚度、基质厚度与年龄均呈负相关（r1=-0．552，P=0．014；r2=-0．545，P=0．035）。上皮层基底膜细胞密度与年龄呈负相关（r=-0．355，P=0．017）。前基质、后基质细胞密度与年龄均呈负相关（r1=-0．462；P=0．001；r2=-0．403，P=0．016）。内皮细胞密度与年龄呈负相关（r=-0．603，P=0．006）。随着年龄的增长，角膜内皮细胞发生了形态学改变，内皮细胞的多形性百分比增大，六边形细胞数的百分比下降（r1=0．417，P=0．004；r2=-0．598，P=0．002）。结论近视人群中央角膜组织随着年龄的增长，角膜上皮基底膜细胞、角膜基质细胞、角膜内皮细胞数量下降，角膜全层、角膜基质厚度减少。     

Structural changes in the cornea after LASIK-u during the early postoperative period

PURPOSE: The study aimed to evaluate in vivo the corneal structure after refractive surgery and monitor morphologic and morphometric changes in the post-operative period. MATERIAL AND METHODS: The study included 35 eyes (25 patients) who underwent LASIK correction of myopia. The structure of the cornea was evaluated in vivo using a scanning slit confocal microscope. Each cornea was examined before, 2, 4 and 8 weeks after procedure. The keratocyte density was evaluated morphometrically in the anterior and posterior corneal stroma. RESULTS: Before surgery the keratocyte density in the anterior stroma ranged from 900 to 1200/mm2, while in the posterior stroma it ranged from 600 to 950/mm2. 8 weeks after LASIK the keratocyte density in anterior stroma ranged from 695 to 1048/mm2 and in posterior stroma from 565 to 935/mm2. CONCLUSIONS: After LASIK the keratocyte density decreases in anterior stroma while in posterior stoma it is constant.     

In vivo corneal confocal microscopy in keratoconus

PURPOSE: To evaluate the corneas of keratoconic subjects using in vivo confocal microscopy. METHODS: Slit scanning confocal microscopy was used to evaluate the central cornea of one eye of each of 29 keratoconic subjects (mean age 31 +/- 10 years; range 16-49 years). Quantitative aspects of corneal morphology were compared against data from control subjects. RESULTS: Compared with normal control corneas, epithelial wing cell nuclei were larger (p < 0.0001) and epithelial basal cell diameter was larger (p < 0.05) in the keratoconic cornea. Many of the keratoconic corneas investigated showed increased levels of stromal haze and reflectivity, which appeared to be related to the presence of apical scarring on slit lamp examination. A grading scale was devised to quantify the levels of haze. This scale was shown to provide a measure of the level of scarring present. The anterior keratocyte density (AKD) and posterior keratocyte density were 19% lower (p < 0.0001) and 10% lower (p = 0.004) than in controls, respectively. The reduction in AKD was significantly associated with three factors: a history of atopy, eye rubbing and the presence of corneal staining. The mean endothelial cell density in keratoconus was 6% greater than that of normal controls (p = 0.05). The level of endothelial polymegethism was shown not to be different between keratoconic subjects and matched controls (paired t-test: t = 1.82, p = 0.08). CONCLUSIONS: Confocal microscopy demonstrates significant quantitative alterations of corneal morphology in keratoconus.