Rigid contact lens fitting based on keratometry readings in keratoconus patients: predicting formula

AIM: To find a simple mathematical correlation between the lens base curve (BC) and keratometry findings (krf). METHODS: This retrospective study included 400 keratoconic eyes (350 patients) previously fit with rigid contact lenses at an academic eye center over a five year period. The patients were classified into five groups based on the keratometry findings (krf<7, krf:7-8, krf>8, krf-krs (difference between two keratometry; flat and steep)= 0.3-0.6, krf-krs >0.6mm as groups 1 to 5, respectively. Multivariate linear regression and Munro's correlation coefficient were employed to defer the formulas. RESULTS: A linear correlation could be found in all groups except for patients in group 3. For group 1, BC=0.211×krf+ 5.904. For group 2, BC=0.456×krf+4.160. For group 4,BC= 0.321×krf+5.219. For group 5, BC=0.337×krf+ 5.090. CONCLUSION: The development of new formulas for RGP fitting enables ophthalmologists to work with confidence and prevents unnecessary and frequent lens trials. The customary lens fitting methods are needed to be replaced by new formulas, which help to save time and costs.     

圆锥角膜患者基于角膜曲率验配硬性隐形眼镜的预测公式

目的:探讨隐形眼镜基线(BC)和角膜曲率结果(Krf)之间简单的数学相关性。方法:本回顾性研究包括350例400只圆锥角膜的眼睛,其先前五年在学院眼科中心验配硬性隐形眼镜。根据角膜曲率结果患者被分为五组,分别为Krf<7,Krf:7-8,Krf>8,Krf-Krs(两个角膜曲率的差异;平坦和陡峭)=0.3-0.6,Krf-Krs>0.6mm1至5组,使用多元线性回归和蒙罗相关系数推测公式。结果:除了第3组患者,可以在所有组中发现线性相关。第1组,BC=0.211×5.904Krf。第2组,BC=0.456×Krf4.160。第4组,BC=0.321×5.219Krf。第5组,BC=0.337×Krf+5.090。结论:RGP验配新公式的发展,可增强眼科医生工作的信心,避免不必要的和频繁的眼镜试验。通常的隐形眼镜验配方法需要更换新的公式,从而帮助节省时间和费用。     

Rigid contact lens fitting based on keratometry readings in keratoconus patients:predicting formula

AIM:To find a simple mathematical correlation between the lens base curve(BC) and keratometry findings(krf).METHODS:This retrospective study included 400 keratoconic eyes(350 patients) previously fit with rigid contact lenses at an academic eye center over a five year period.The patients were classified into five groups based on the keratometry findings(krf<7,krf:7-8,krf>8,krf-krs(difference between two keratometry;flat and steep)= 0.3-0.6,krf-krs >0.6mm as groups 1 to 5,respectively.Multivariate linear regression and Munro’s correlation coefficient were employed to defer the formulas.RESULTS:A linear correlation could be found in all groups except for patients in group 3.For group 1,BC=0.211×krf+ 5.904.For group 2,BC=0.456×krf+4.160.For group 4,BC= 0.321×krf+5.219.For group 5,BC=0.337×krf+ 5.090.CONCLUSION:The development of new formulas for RGP fitting enables ophthalmologists to work with confidence and prevents unnecessary and frequent lens trials.The customary lens fitting methods are needed to be replaced by new formulas,which help to save time and costs.     

Prevalence of Orbscan II corneal abnormalities in relatives of patients with keratoconus

Background: To determine the prevalence of Orbscan II‐derived keratoconus traits in relations of individuals with keratoconus and a control group and to apply these to a pedigree analysis. Methods: In a controlled, prospective, observational case series, four Orbscan II‐derived corneal parameters were examined in relations of individuals with keratoconus and a control group of low myopes (<2.5 D). The four parameters and thresholds for abnormality (derived from a literature review) were as follows: average keratometry (≥47.2 D), I‐S value (≥1.2 D), posterior float apex (≥42 µm) and thinnest pachymetry (≤463 µm). Results: Forty‐four unrelated controls (88 eyes) and eight families with 90 members without known (178 eyes) and 11 members with keratoconus (19 eyes) were analysed. One of 88 (1.14%) control eyes had a single keratoconus trait, and none had more than one trait. Of 178 eyes from relatives of patients with keratoconus, 45 (25.3%) had one or more keratoconus traits. Relatives of patients with keratoconus had an elevated risk of possessing a keratoconus trait (relative risk 14.67, CI 2.07–104.07, P < 0.001) compared with controls. Approximately 53.3% of relatives with a keratoconus trait were evident on either pachymetric or posterior elevation indices alone. Six of eight families suggested dominant inheritance. Conclusions: Keratoconus traits are common in relatives of patients with keratoconus. There prevalence may have been previously underestimated by using placido image‐based topography alone where corneal pachymetry and posterior elevation are not assessed. This study suggests an autosomal dominant pattern of inheritance with variable expressivity in some families.     

Longitudinal study of keratoconus progression

To determine if differences in topographic progression between unaffected keratoconus relatives and normal controls can predict factors associated with the development of keratoconus in a longitudinal study. We recruited 369 unaffected keratoconus relatives and 119 normal controls in Los Angeles. Both eyes of subjects were examined at baseline clinically and by quantitative videokeratography and at a period ranging from 1 year to 8 years. Progression to keratoconus was evaluated by quantitative videokeratography variables. Unaffected relatives had higher Central K (CK), I-S and KISA values and were younger than normal controls (CK: 44.70 vs 44.01, P<0.01; I-S: 0.76 vs 0.58, P<0.01, KISA: 29.97 vs 23.89, P=0.02; age: 34.8 vs 41.0, P<0.01) at baseline. All three indices significantly increased with age, and CK and KISA values were associated with a positive family history for keratoconus (P<0.001 for CK and P=0.05 for KISA), however, the two groups were not statistically different in progression of keratoconus. After grouping unaffected relatives as high risk (age< or = 30 or Central K > or = 47.2 and I-S> or =1.2 or KISA> or = 60) and low risk (age>30 and Central K<47.2 and I-S<1.2 and KISA< 60), relatives in the high risk group had a greater increase in CK and I-S values than those in the low risk group (CK: P=0.009; I-S: P<0.001), which indicated that there were significantly different rates of progression between two groups. Unaffected relatives had higher videokeratography indices than normal controls, but overall they did not progress to keratoconus quicker than normal controls. However, relatives in the high risk group may have a greater risk of progression to keratoconus.     

Three-year follow-up in advanced pediatric keratoconus: thin corneas may not have pachymetry properly assessed after crosslinking

AIM: To analyze the crosslinking (CXL) effects in pediatric keratoconus, and to identify the patients’ corneal characteristics whose pachymetry could not be adequately evaluated by Scheimpflug method after procedure. METHODS: Consecutive pediatric patients with progressive keratoconus underwent CXL were included. Best-corrected visual acuity (BCVA) and spheric equivalent (SE) were measured before and after CXL. After CXL, groups 1 and 2 were divided based on the posterior surface Pentacam quality specifications (QS): “OK” (Group 1) and “not OK” (Group 2). The mean (RmF and RmB) and minimum (RminF and RminB) radius of curvatures of the anterior and posterior corneal surfaces, and the thinnest pachymetry (Pmin) were measured preoperatively at 3, 6, 12, 24, and 36mo. Haze was annotated. RESULTS: Twenty-six patients (14 men, mean age 14±1.8y) and median Kmax of 59.9 D initially and 61.4 D preoperatively were treated. BCVA was not different before and 24mo after CXL. Group 2 statistically differed to group 1 in that SE was more myopic before and with no difference 24mo after CXL; RmF and RmB were steeper and Pmin was thinner pre-surgically. Group 2, in which pachymetric changes could not be adequately evaluated after surgery, presented with significant RmF flattening, a shift to hyperopia, and more haze after CXL. CONCLUSION: Patients whose pachymetry could not be adequately evaluated after CXL had steeper and thinner corneas before surgery. The predictive factors for impaired QS after CXL are RmF, RmB, and Pmin. In advanced keratoconus, alternative methods to analyze pachymetry and the posterior surface should be considered.     

Epithelial remodelling masquerading as keratoconus progression: An interesting case report

A 25-year-old male patient presented with chief complaints of itching in both eyes (OU) for the past one month. Detailed ophthalmic examination showed best-corrected visual acuity of 6/6 OU. On slit-lamp examination of the left eye, Vogt''s striae were documented and rest of the anterior segment was normal OU. Pentacam-HR and ASOCT confirmed the diagnosis of keratoconus. The patient was started on Trehalose containing preparation for both eyes. On follow-up visit at 8 months, progression was documented on Pentacam-HR. MS-39 showed epithelial remodeling, but no stromal or posterior elevation, indicative of a pseudo-progression. Corneal epithelial remodeling post topical trehalose containing eye drops application has been very sparsely reported in literature. It is an important differential to consider when faced with a situation of a likely progression of keratoconus, especially to differentiate true from pseudo-progression.     

Comparability and repeatability of pachymetry in keratoconus using four noncontact techniques

Purpose:To compare and determine the repeatability of central corneal thickness (CCT) measurements using four noncontact pachymetry instruments in eyes with keratoconus.Results:Fifty eyes of 25 participants were analyzed in this study. All measurement methods correlated well with each other (r > 0.9, P < 0.001). Mean ± standard deviation CCT measured by HHSD-OCT, Orbscan IIz, SS-OCT, and Pentacam was 462 ± 41 μm, 458 ± 41 μm, 454 ± 40 μm, and 447 ± 42 μm, respectively. While the HHSD-OCT over-estimated the CCT (P < 0.001), there was a good correlation between the measurements obtained from the other three devices. However, the numerical difference was high and this trend was seen in all the paired comparisons.Conclusions:Though the measurements by different devices correlated well, the numerical agreement may be inadequate for their interchangeable use in clinical practice.     

角膜胶原交联术治疗圆锥角膜的疗效和安全性研究

目的：研究角膜胶原交联术治疗圆锥角膜的疗效和安全性。

方法：对2015-04/2018-08在泰国朱拉隆功国王纪念医院行角膜胶原交联术的圆锥角膜患者病历进行回顾性分析。评估术前和术后1a的视力、屈光度、角膜地形图、高阶像差(HOA)、地形图参数和角膜密度。根据患者年龄是否小于24和30岁、基线角膜最大曲率(Kmax)是否小于55 D、基线最佳矫正视力(BCVA)是否小于0.3 LogMAR分组评估年龄、基线Kmax和BCVA对手术疗效的影响。分析术前Kmax、Kmean、平均等效球镜度数(MRSE)、视力、角膜最薄点厚度值、Kmax的变化以及相关参数的变化与角膜密度测量值变化之间的关系。P<0.05具有统计学意义。

结果：共155例患者185眼纳入研究,其中119例男性,36例女性。根据Amsler-Krumeich进行分类,1期和2期占优势(分别为37.84%和35.14%)。术后1a,平均裸眼视力(UCVA)提高0.1 LogMAR(P<0.05)。与基线BCVA较好组(术前BCVA<0.3 LogMAR)相比,基线BCVA较差组(术前BCVA≥0.3 LogMAR)术后BCVA改善大于0.2 LogMAR的眼数较多(78.26% vs 21.74%,P<0.05)。平均Kmax比基线下降2.36 D(P<0.05)。术前Kmax≥55 D的患眼术后Kmax下降超过2.0 D的眼数占比73%。距角膜顶点6 mm处角膜HOA下降0.40(P<0.05)。术后1mo～1a,0～6 mm区角膜密度测量值持续增加。术后1a,角膜密度的增加与最薄点厚度的减少呈线性相关。表面变异指数、高度非对称性指数、圆锥角膜指数、高度轴偏心指数在术后1a时下降(P<0.05)。术后1a,手术成功率为90.24%。术后1wk、1、3、6mo、1a角膜混浊发生率分别为11.35%、30.27%、15.67%、10.27%、2.16%。无角膜水肿发生,但有1例无菌性角膜炎患者。

结论：角膜胶原交联术可有效治疗圆锥角膜,使角膜变平、重塑,提高视力、HOA和角膜形态指数,晚期圆锥角膜Kmax也明显降低。     

不同进展期圆锥角膜生物力学研究

目的:探讨可视化角膜生物力学分析仪(Corvis ST)测量正常角膜、顿挫期圆锥角膜、亚临床期圆锥角膜、临床期圆锥角膜的生物力学变化,分析不同进展期圆锥角膜生物力学特征,为更早期地诊断圆锥角膜提供临床依据.方法:病例对照研究.选取顿挫期圆锥角膜15眼为顿挫组,亚临床期圆锥角膜23眼为亚临床期组,临床期圆锥角膜40眼为圆锥角膜组,欲行近视激光手术和正常角膜志愿者40眼为正常组(对照组),应用Corvis ST测定各组的生物力学参数,并进行比较分析,绘制受试者工作曲线(ROC).结果:正常角膜与顿挫期圆锥角膜生物力学各参数差异均无统计学意义(P>0.05).正常角膜与亚临床期组第二压平长度(AL2)、第一压平速率(AV1)、最大压陷曲率半径(HC-radius)、最大压陷深度(DA)间的差异有统计学意义(P<0.05).正常角膜与圆锥角膜组除第二压平速度(AV2)、最大压陷时间(HC-time)、最大压陷屈膝峰间距(PD)差异无统计学意义外,其余生物力学数据差异均有统计学意义(P<0.05),ROC曲线分析DA对于圆锥角膜诊断效率最高(曲线下面积0.891±0.028).结论:顿挫期圆锥角膜生物力学较正常角膜无改变,亚临床期圆锥角膜生物力学较正常角膜部分参数有改变,但其参数单独诊断圆锥角膜特异性和敏感性均较差.临床期圆锥角膜生物力学较正常角膜明显改变,DA诊断效率最高.     

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.     

三种仪器测量圆锥角膜中央角膜厚度的对比研究

目的:对比A型超声角膜测厚仪、角膜内皮镜和Pentacam眼前节分析仪测量圆锥角膜中央角膜厚度的差异。方法:选择2012-07/10圆锥角膜患者31例55眼,分别使用A型超声角膜测厚仪、角膜内皮镜和Pentacam眼前节分析仪测量中央角膜厚度,并对测量结果进行F检验和Pearson相关性分析。结果:A型超声(55眼)、角膜内皮镜(45眼)和Pentacam(52眼)测量值分别为469.87±57.56,479.00±42.39,487.02±44.64μm,三者测量值结果相比差异没有统计学意义(P>0.05)。对三种仪器的测量结果进行直线相关分析,A型超声与角膜内皮镜,r1=0.758,P<0.01;A型超声与Pentacam眼前节分析仪,r2=0.949,P<0.01;Pentacam眼前节分析仪与角膜内皮镜,r3=0.685,P<0.01。结论:三种仪器的中央角膜厚度测量值存在正相关,Pentacam眼前节分析仪测量角膜厚度不仅与A超结果更接近,而且方法安全简便,全面反应角膜各点厚度,更适用于圆锥角膜患者的角膜厚度检查及科研研究。     

核黄素角膜胶原交联治疗早期轻中度圆锥角膜的研究

目的：核黄素角膜胶原交联早期治疗轻度至中度圆锥角膜的预后。

方法：三级眼科诊疗中心的前瞻性研究。共38例47眼轻至中度圆锥角膜接受核黄素角膜胶原交联治疗的患者纳入本研究。术前数据包括参与眼数,视力,眼压,角膜厚度与角膜地形图。术后数据包括最佳矫正视力,眼压,角膜厚度,角膜地形图和术后并发症。

结果：研究包含年龄16～30岁的患者38例47眼。平均术前视力为0.58±0.40 logMAR,术后随访2a显著提高(0.40±0.27logMAR)(P=0.005)。平均术前角膜曲率为50.5±4.6 D,术后显著降低。随访2a平均角膜曲率为48.2±4.1 D(P=0.011)。术后随访2a眼压(15.1±3.0mmHg)较术前(12.9±2.5 mmHg)显著增加(P=0.035)。术前角膜厚度467.9±38.8 μm,术后随访2a(465.0±39.3 μm)明显降低。所有患者均无并发症出现。

结论：早期使用核黄素角膜胶原交联治疗轻至中度圆锥角膜可获得长期的良好视力,而不必等其发展为进展期。     

A novel analysis of Scheimpflug total corneal refractive power following corneal cross-linking in mild to moderate keratoconus

AIM: To detect an earlier improvement in mild to moderate keratoconus following corneal cross-linking (CXL) with total corneal refractive power (TCRP) using ray tracing method. METHODS: A total of 40 eyes of 30 consecutive patients who underwent CXL for progressive keratoconus were retrospectively enrolled. The following keratometric parameters provided by Pentacam HR, including maximum keratometry (Kmax), steepest keratometry (Ksteep), 3 mm zonal TCRP centered over corneal apex (TCRPapex,zone 3 mm), zonal mean keratometry and TCRP centered over corneal cone (Kmcone,zone and TCRPcone,zone 1, 2, 3 mm) were evaluated preoperatively and 1, 3, 6, and 12mo postoperatively. Groups 1 and 2 were defined based on Kmax at postoperative 1mo as improved (the initial improvement group) or worsen (the initial deterioration group) compared to the preoperative level. RESULTS: In the overall group, only keratometric parameters based on ray tracing method displayed significant improvement early at 3mo postoperatively, in which TCRPcone,zone 1 mm and 2 mm exhibited the largest flattening (0.57 D and 0.53 D, respectively). In Group 1, only Kmax, Kmcone,zone 2 mm and TCRPcone,zone 2 mm showed significant improvement initially at 1mo postoperatively, in which Kmax exhibited the largest improvement (1.05 D), followed by TCRPcone,zone 2 mm (0.82 D). In Group 2, only keratometric parameters based on ray tracing method and Kmcone,zone 3 mm showed slight but not significant improvement early at 3mo, in which TCRPcone,zone 3 mm displayed the most improvement (0.19 D), followed by TCRPcone,zone 2 mm (0.15 D). CONCLUSION: The findings indicate that a 2 mm zonal TCRP centered over Kmax could earlier detect keratometric improvement by CXL compared to other commonly used parameters in mild to moderate keratoconic eyes.     

Involvement of corneal nerves in the progression of keratoconus

Keratoconus is a debilitating corneal thinning disease that principally develops in the second and third decades of life. Our group previously developed a novel approach to studying keratoconus, based on the observation that there is a gradient of damage across the keratoconic cone.We identified a number of cellular characteristics of keratoconus such as discrete incursions of fine cellular processes from the anterior keratocytes in association with localised indentation of the basal epithelium, and increased levels of the lysosomal enzymes Cathepsin B and G in aberrant keratocytes, located beneath compromised regions of Bowman's layer, but also deeper in the stroma. Enzyme activity by these cells seemed to be causing localised structural degradation of the anterior stroma, leading to near-complete destruction of both Bowman's layer and the stroma, often necessitating a full-thickness corneal graft for sight restoration.This current study extends our initial findings by investigating the role of corneal nerves passing between the stroma and epithelium at the sites of early degradative change observed previously, and may be facilitating the keratocyte-epithelial interactions in this disease.Cells in sections of normal and keratoconic human corneas were labelled with the fixable fluorescent viability dye 5-chloromethylfluorescein diacetate, antibodies to alpha-tubulin (nerves), alpha3beta1 integrin, Cathepsin B and G, and the nuclear dye DAPI, and then examined with a confocal microscope. Anterior keratocyte nuclei were seen wrapping around the nerves as they passed through the otherwise acellular Bowman's layer, and as the disease progressed and Bowman's layer degraded, these keratocytes were seen to express higher levels of Cathepsin B and G, and become displaced anteriorly into to the epithelium. Localised nerve thickenings also developed within the epithelium in association with Cathepsin B and G expression, and appeared to be very destructive to the cornea.Insight into the molecular mechanisms of keratoconic disease pathogenesis and progression can be gained from the process of extracellular matrix remodelling known from studies of connective tissues other than the cornea, and wound healing studies in the cornea. Further studies are required to determine how well this model fits the actual molecular basis of the pathogenesis of keratoconus.     

Correlation of basic indicators with stages of keratoconus assessed by Pentacam tomography

AIM: To evaluate the diagnostic efficiency of basic indicators and find characteristic indicators for keratoconus (KC) at adjacent stages, and to assess the progression pattern of KC. METHODS: One hundred and eight (41 subclinical, 40 moderate, and 27 severe) keratoconic patients (108 eyes) and 105 myopic patients (105 eyes) as controls were recruited in this prospective, comparative case series study. Pentacam topography was performed. Receiver-operating-characteristic curves were used to get the characteristic indicators. RESULTS: The most efficient distinguishing index between the subclinical KC and the controls was posterior elevation value (PEV, AUC=0.882), with the highest specificity being 93.8%. Corneal thickness (AUC=0.852) and posterior inferior-superior value (I-S) ranked second and third (AUC=0.776). When KC became moderate, PEV remained to be of the highest diagnostic efficiency (AUC=0.988), followed by the anterior elevation value (AUC=0.986) and other parameters of anterior surface. The diagnostic value increased significantly in the anterior curvature indices (all AUC>0.900) and appeared in the anterior best fitting sphere radius (AUC=0.919) when KC developed into the severe stage. CONCLUSION: In the subclinical stage of KC, PEV, thickness, and posterior I-S had important diagnostic values, and elevation values remained most efficient when KC developed to the moderate stage. The anterior curvature indices were most characteristic when KC became severe. KC first appeared in the inferior cornea of posterior surface, but the feature of protrusion formed at the moderate stage.     

Pentacam眼前节分析仪检查参数对早期圆锥角膜的诊断价值

目的：分析Pentacam眼前节分析仪检查参数对早期圆锥角膜的诊断价值。

方法：回顾性对照研究,选取2019-01/2020-01于我院就诊的圆锥角膜患者100例124眼作为研究组,根据Amsler-Krumeich分级法将圆锥角膜患者按照严重程度分为轻度组(51眼)、中度组(43眼)和重度组(30眼),另外选取30名屈光度<-3.00D且无散光体检正常者右眼作为对照组,比较各组Pentacam眼前节分析仪参数\〖3mm直径范围水平中央曲率(K1)、3mm直径范围垂直中央曲率(K2)、角膜前表面最大屈光力(Kmax)、角膜散光(Cyl)、角膜最薄处的厚度(thinnest local)、角膜表面变异指数(ISV)、垂直不对称指数(IVA)、圆锥角膜指数(KI)、前房容积(ACV)以及前房深度(ACD)\〗情况,通过ROC曲线分析诊断早期圆锥角膜的敏感指标。

结果：研究组患者K1、K2、Kmax、Cyl、ISV、IVA、KI、ACD均明显高于对照组(P<0.05),thinnest local、ACV均明显低于对照组(P<0.05); 不同严重程度圆锥角膜患者的K1、K2、Kmax、Cyl、thinnest local、ISV、IVA、KI、ACV、ACD差异均有统计学意义(P<0.05),中度组和重度组K1、K2、Kmax、Cyl、ISV、IVA、KI、ACD均明显高于轻度组(P<0.05),thinnest local、ACV均明显低于轻度组(P<0.05),中度组和重度组K1、K2、Kmax、Cyl、thinnest local、ISV、IVA、KI、ACV、ACD比较有差异P<0.05); ROC诊断曲线结果显示,Kmax、thinnest local、ISV、IVA、KI是诊断圆锥角膜的敏感指标(AUC>0.85),其中ISV的诊断价值最高。

结论：Pentacam眼前节分析仪可有效测量圆锥角膜参数,不同严重程度圆锥角膜患者参数存在差异,其中Kmax、thinnest local、ISV、IVA、KI是诊断早期圆锥角膜的敏感指标,Pentacam眼前节分析仪检查参数对早期圆锥角膜具有较高的诊断价值。