目的 了解圆锥角膜的角膜地形图改变。方法 应用Orbscan角膜地形图系统检测35例（47只眼）圆锥角膜患者的角膜，对其角膜中心点、锥顶、角膜后表面最高点、角膜屈光度最大点和角膜最薄点的位置、角膜前表面高度、角膜屈光度及角膜厚度，以及角膜屈光度和角膜前表面高度的关系进行分析。结果 圆锥角膜锥顶的高度平均为（01102±01044）mm，距角膜中心点的距离为（01686±01376）mm。圆锥角膜锥顶、角膜后表面最高点和角膜屈光度最大点的位置分布以颞下最多，其他依次为鼻下、颞上、鼻上，最薄点以鼻下方为多，其次为颞下。圆锥角膜的角膜曲率为（6019±1014/5314±817）D，角膜中央直径3mm、5mm内平均屈光度数分别为（5711±810）D、（5017±514）D。圆锥角膜锥顶的高度与此点的屈光度数呈明显的正相关（r=01697，P<0101），与此点的角膜厚度呈负相关（r=-01563，P<0101）。结论 Orbscan角膜地形图系统可为早期诊断圆锥角膜并提供形态学依据。

目的 了解正常人的角膜前后表面形态及全角膜厚度，为诊断异常角膜提供参考依据。方法应用Orbscan角膜地形图仪对46例正常人（46 只眼）的角膜进行检测，建立其正常参数。结果正常人角膜最薄处为（0155±0133）mm，平均位于距视轴（0190±0151）mm 处。32例（70%）角膜最薄点位于颞下方，11例（24%）位于颞上方，2例（4%）位于鼻下，1例（2%）位于鼻上方。角膜厚度以角膜中央最薄（0156±0103）mm，角膜上方最厚（0164±0103）mm。模拟角膜屈率（Sim K）为（44124 ±1161/43131±1166）D，散光度为（0190±0141）D。角膜前表面高度地形图的图形中，岛形最多，其次为不完全嵴形。角膜后表面高度地形图的图形中，岛形最多，其次为规则嵴形及不完全嵴形。在前表面角膜屈率地形图的图形中，对称蝴蝶结形最多，其次为椭圆形及不对称蝴蝶结形。在角膜厚度彩色地形图中，椭圆形最多，其次为圆形。结论了解正常人全角膜厚度、角膜高度形态及角膜前表面角膜屈率地形图将为诊断异常角膜提供依据。Orbscan角膜地形图仪是一种测量角膜地形及全角膜厚度的有用工具，在角膜屈光手术中将具有重要的应用价值。

Purpose: To evaluate corneal surface regularity and the effect of artificial tears on the regularity of the corneal surface in dry eye. Design: A prospective, clinic-based, case-control study. Participants: A total of 64 eyes of 33 normal subjects and 42 eyes of 22 patients with aqueous tear deficiency were evaluated. Methods: Indices of the TMS-1 corneal topography instrument (Tomey Technology, Cambridge, MA) were used to evaluate corneal surface regularity and potential visual acuity (PVA) in patients with aqueous tear deficiency dry eye before and after the instillation of artificial tears and in normal subjects. The TMS-1 topographic maps were classified into round, oval, symmetric bow-tie, asymmetric bow-tie, and irregular patterns. Main Outcome Measures: The surface regularity index (SRI), surface asymmetry index (SAI), PVA index, and topographic pattern of the TMS-1 were compared between normal and dry eyes and in dry eyes before and after the instillation of artificial tears. Results: The SRI and SAI were significantly elevated and the PVA was significantly reduced in dry eye patients compared with normal subjects: 0.31

目的 评价干眼病患者的角膜表面规则性及人工泪液对其角膜表面规则性的影响。方法应用TMS21角膜地形图仪检测正常人33例（64只眼）及干眼病患者22例（42只眼）的角膜表面规则指数（surfaceregularityindex，SRI）、表面不对称指数（surfaceasymmetryindex，SAI）及角膜预测视力（potentialvisualacuity，PVA），并对干眼病患者应用人工泪液前后角膜表面规则性及PVA的变化进行观察。结果 干眼病患者的SRI、SAI及PVA值分别为0.31±0.22、0.30±0.16及20/17.89±20/3.04;而正常人分别为1.28±0.73、1.05±1.17及20/33.45±20/13.99。干眼病患者的SRI和SAI值较正常人明显升高，PVA值则明显降低，各组间比较差异有非常显著性（P<0.001）。干眼病患者的平均散光度（2.10±1.96）D明显较正常人（1.13±0.53）D高（P=0.02）。在干眼病患者中，SRI与SAI与角膜荧光素染色程度呈正相关（SRI:P=0.005；SAI:P=0.016），而平均PVA与平均实际矫正视力比较差异无显著性。干眼病患者角膜地形图中对称蝴蝶结形所占的比例较正常人明显降低，而不规则形者所占比例则明显升高。干眼病患者在滴用人工泪液后，SRI、SAI和平均散光度均明显降低（P值分别为<0.001，<0.002，0.04），而PVA则明显升高（P<0.001）。45.2%干眼病患者的角膜地形图为不规则形，应用人工泪液后不规则形降至31.0%。结论 干眼病患者的角膜表面不规则性增加可能是导致此类患者视力障碍的原因。SRI和SAI可以作为诊断干眼病的客观指标，并可用于评价干眼病的严重程度及人工泪液的疗效。人工泪液可改善干眼病患者的角膜表面光滑度。

Purpose: To evaluate two indices generated from measurements obtained from the Orbscan Corneal Topography System (CTS; Orbscan, Inc., Salt Lake City, UT) to distinguish contact lens-induced corneal thinning from keratoconus. The corneal thickness index (CTI) was used to compare central and peripheral corneal thicknesses. The discriminant function 1 (DF1) was used to evaluate corneal thickness and central keratometry measurements. Design: Case-control study. Participants: Fifty-four patients with keratoconus or suspected keratoconus, 75 contact lens wearers, and 67 normal controls. Methods: In the initial model-building study, the central and peripheral corneal thickness and central keratometry (K) readings were evaluated retrospectively in 1 eye each of 23 patients with clinically defined keratoconus, 31 contact lens wearers, and 43 normal patients with the Orbscan CTS. Two methods (corneal thickness index [CTI] and discriminant function 1 [DF1]) were evaluated for their efficacy in classifying these conditions. The CTI was designed as the ratio between mean peripheral corneal thickness and the central corneal thickness, and the formula for the DF1 was as follows: DF1 =0.044

目的：了解长期配戴角膜接触镜对角膜厚度、屈率及表面规则性的影响。方法：应用Orbscan角膜地形图系统检测35例（64只眼）配戴角膜接触镜5年以上患者的全角膜厚度、前表面角膜屈率及角膜前、后表面高度地形图。20例（40只眼）正常人为正常对照。采用TMS21角膜地形图系统的参数评价角膜表面规则性。比较正常人和配戴角膜接触镜5年以上患者的全角膜厚度、角膜屈率、表面规则指数（SRI）、表面不对称指数（SAI）、预测视力（PVA）及角膜地形图图形的差异。结果：戴镜组病例其配戴角膜接触镜的平均时间为（13145±6142）年。与正常对照组相比，长期配戴角膜接触镜患者其角膜中央及周边8个测量区的平均角膜厚度减少30～50μm（P<01001），角膜屈率、最大角膜屈率（MaxK）及最小角膜屈率（MinK）明显增加（P<0101）。两组间角膜散光度无显著性差异。长期配戴角膜接触镜的患者其TSM21系统参数中的SRI和SAI值较正常人明显增加（P<0101），PVA值无明显改变（P=0115）。应用两种角膜地形图仪检查所得的角膜屈率地形图及角膜高度地形图的彩色编码图形类型，两组间无显著性差异。结论：长期配戴角膜接触镜将导致全角膜厚度减小、角膜屈率增加及角膜表面不规则性增加。

Aims-To map the thickness, elevation (anterior and posterior corneal surface), and axial curvature of the cornea in normal eyes with the Orbscan corneal topography system. Methods-94 eyes of 51 normal subjects were investigated using the Orbscan corneal topography system. The anterior and posterior corneal elevation maps were classified into regular ridge, irregular ridge, incomplete ridge, island, and unclassified patterns, and the axial power maps were grouped into round, oval, symmetric bow tie, asymmetric bow tie, and irregular patterns. The pachymetry patterns were designated as round, oval, decentred round, and decentred oval. Results-The thinnest point on the cornea was located at an average of 0.90 (SD 0.51)mm from visual axis and had an average thickness of 0.55 (0.03)mm. In 69.57% of eyes, this point was located in the inferotemporal quadrant, followed by the superotemporal quadrant in 23.91%, the inferonasal quadrant in 4.35%, and the superonasal quadrant in 2.17%. Among the nine regions of the cornea evaluated (central, superotemporal, temporal, inferotemporal, inferior, inferonasal, nasal, superonasal, and superior) the central cornea had the lowest average thickness (0.56 (0.03)mm) and the superior cornea had the greatest average thickness (0.64 (0.03) mm). The mean simulated keratometry (SimK) was 44.24 (1.61)/43.31 (1.66) dioptres (D) and the mean astigmatism was 0.90 (0.41) D. Island (71.74%) was the most common elevation pattern observed in the anterior corneal surface, followed by incomplete ridge (19.57%), regular ridge (4.34%), irregular ridge (2.17%), and unclassified (2.17%). Island (32.61%) was the most common topographic pattern in the posterior corneal surface, following by regular ridge (30.43%), incomplete ridge (23.91%), and irregular ridge (13.04%) patterns. Symmetric bow tie was the most common axial power pattern in the anterior cornea (39.13%), followed by oval (26.07%), asymmetric bow tie (23.91%), round (6.52%), and irregular (4.53%) patterns. In the pachymetry maps, 47.83% of eyes had an oval pattern, and round, decentred oval, and decentred round were observed in 41.30%, 8.70%, and 2.18% of eyes, respectively. Conclusion—The information on regional corneal thickness, corneal elevation and axial corneal curvature obtained with the Orbscan corneal topography system from normal eyes provides a reference for comparison with diseased corneas. The Orbscan corneal topography system is a useful tool to evaluate both corneal topography and corneal thickness.

Purpose: To evaluate the effect of long-term contact lens wear on corneal thickness, curvature, and surface regularity. Design: A prospective, clinic-based, case-control study. Participants: A total of 40 eyes of 20 normal subjects and 64 eyes of 35 subjects wearing contact lenses for more than 5 years were evaluated. Methods: The Orbscan Corneal Topography System was used to evaluate the entire corneal thickness and curvature, anterior curvature and the anterior and posterior elevation topographic patterns in normal eyes and subjects wearing contact lenses on a regular basis for more than 5 years. Indices of TMS-1 Corneal Topography System were used to determine corneal surface regularity in subjects wearing contact lenses and normal eyes. All topographic examinations were performed after contact lenses had been removed for at least 2 weeks. Main Outcome Measures: The entire corneal thickness, curvature, surface regularity index (SRI), surface asymmetry index (SAI), potential visual acuity (PVA) and topographic patterns were compared between normal eyes and subjects wearing contact lenses for more than 5 years. Results: The 64 eyes of 35 subjects evaluated by the Orbscan instrument had an average of 13.45