两种仪器测量近视患者角膜地形图的对比研究

目的对比OrbscanⅡ和Pentacam眼前节分析仪测量近视患者角膜地形图的差异。方法分别使用OrbscanⅡ和Pentacam眼前节分析仪测量119例近视患者角膜地形图,并对测量结果进行方差分析、配对t检验和Pearson相关分析。结果 OrbscanⅡ和Pentacam测得CCT平均值分别为(515.67±36.06)μm、(539.67±31.41)μm,差异有统计学意义(P<0.05);OrbscanⅡ测得角膜前后表面曲率、前后表面高度和瞳孔直径均显著高于Penta-cam;两种仪器测得角膜散光和前房深度无差异。结论两种仪器测得角膜地形图存在一定差异,在临床工作中不能将二者测量结果简单替代。     

四种方法测量近视患者中央角膜厚度的比较研究

目的探讨超声角膜测厚仪(A超)、Sirius眼前节分析系统、傅立叶域眼前节断层扫描仪(RTVue-OCT)和Orbscan Ⅱ眼前节分析仪测量近视患者中央角膜厚度(central corneal thickness,CCT)的差异及一致性。方法分别用A超、Srius、RTVue-OCT和Orbscan Ⅱ测量近视患者85例(170眼)的CCT,用配对t检验对其差异进行比较,用Bland-Altman分析对其一致性进行检验。结果 A超、Sirius、RTVue-OCT和OrbscanⅡ测得的CCT值分别为(531.77±34.98)μm、(531.84±35.86)μm、(521.34±34.43)μm、(530.78±41.00)μm,RTVue-OCT的测量值最小,与其他3种测量仪结果相比差异均有统计学意义(均为P=0.000),其他3种仪器测量结果相似,差异均无统计学意义(均为P>0.05)。线性相关显示4种测量方法两两之间均存在正相关(均为P=0.000)。Bland-Altman分析显示4种测量方法均有良好的一致性。结论 4种仪器均可以作为CCT的测量工具,但相互替代使用需要慎重。RTVue-OCT测量的CCT值较小,应引起注意。     

近视眼患者角膜后表面地形图的研究

目的　了解近视眼患者角膜后表面形态 ,建立相关参数 ,为准分子激光原位角膜磨镶术 (LASIK)术前筛选病例提供参考依据。方法　应用Orbscan Ⅱ眼前节系统对 484例近视眼患者进行检测 ,分为 0～ -2 75D ,-3 0 0～ -6 0 0D ,-6 2 5～ -9 75D ,-10 0 0～ -14 75D ,-15 0 0D以上 ,共 5组。得出角膜后表面地形分布情况 ,建立相关参数 ,并对后表面参数行相关性分析。结果　各组角膜后表面高度地形图中以岛形居多 ;角膜后表面高度形态及屈光状态不尽相同 ,有其自身特点 ;各组后表面前突极点多位于颞下方 ,依次为鼻下、颞上、鼻上。屈光度与基于同一拟合球面的后表面前突极值、前突极点距视轴距离、前突面积、前突最大与最小值无相关关系 (P >0 0 5 ) ;基于同一拟合球面的后表面前突极值、前突极点距视轴距离、前突面积、前突最大与最小值各指标之间具有相关系数 (P <0 0 5 )。结论　了解近视眼患者角膜后表面高度地形及屈光状态 ,将为诊断异常角膜提供参考依据 ;基于同一拟合球面的后表面前突极值、前突极点距视轴距离、前突面积、前突最大与最小值之差是Orbscan Ⅱ眼前节系统检测角膜后表面地形的良好指标 ;Orbscan Ⅱ眼前节系统在角膜屈光手术中具有广泛应用前景     

LASIK术后角膜生物力学变化与眼压测量值的相关性

目的 观察LASIK术后角膜生物力学参数和眼压测量值的变化及角膜生物力学变化与眼压的相关性。设计 前瞻性病例系列。研究对象 哈尔滨医科大学附属第一医院2014年1-12月LASIK手术患者81例（162眼）。方法 应用非接触眼压计（non-contact tonometer,NCT）分别在术前及术后3个月测量眼压。同时应用眼反应分析仪（ocular response analyzer,ORA）测量角膜滞后量（corneal hysteresis,CH）、角膜阻力因子（corneal resistance factor, CRF）、模拟Goldmann 眼压（Goldmann intraocular pressure,IOPg）和角膜补偿眼压（corneal-compensated intraocular pressure,IOPcc）。比较手术前后各参数的变化并分析术后角膜生物力学参数变化与眼压测量值的相关性。 主要指标 手术前后NCT、IOPcc、IOPg、CH、CRF。 结果 LASIK术后3个月CH、CRF、IOPcc、IOPg、NCT测量值与术前比较均显著降低,术后IOPcc与IOPg和NCT之间比较差异均有统计学意义（P<0.05）;△CH、△CRF与△IOPcc、△IOPcc- IOPg和△IOPcc-△NCT均成负相关,△CH、△CRF与△IOPg和△NCT均成正相关（P<0.05）;CH和CRF的减少量与眼压测量值下降具有相关性（P<0.05）。结论 LASIK术后角膜生物力学参数和眼压测量值均较术前显著降低,眼压测量值下降与CH和CRF的减少量具有相关性,说明眼压下降的程度可能受角膜生物力学特性的影响。     

Corvis ST与常用眼压计及角膜测厚仪在测量眼压及角膜厚度中的应用

目的：比较可视化角膜生物力学分析仪（Corvis ST）与三维眼前节分析仪（Pentacam）、非接触式眼 压计（NCT）、A型超声角膜测厚仪（A超）、光学生物眼科测量仪（Lenstar）在测量眼压及中央角膜 厚度的差异。方法：前瞻性研究。纳入2020年8—12月佛山市第二人民医院屈光术前近视患者110 例,将Corvis ST 眼压（IOP）及校正眼压（BIOP）、NCT眼压与Pentacam对NCT的校正眼压纳入眼压 指标;将Corvis ST的中央角膜厚度、Pentacam的最薄点中央角膜厚度、Lenstar的角膜厚度、A超的 角膜厚度纳入角膜厚度指标。眼压与角膜厚度的差异对比采用单因素方差分析法,相关性分析采 用Pearson方法,一致性检验采用Bland-Altman。结果：眼压：Corvis ST分别与NCT、Pentacam所测 量的眼压值在组间比较差异无统计学意义,其中Corvis ST分别与NCT、Pentacam测量的眼压值比 较差异有统计学意义（P=0.019; P=0.03）。IOP与NCT眼压、Pentacam校正眼压呈正相关性（r=0.76, P ＜0.001; r=0.65, P＜0.001）,BIOP与NCT眼压、Pentacam校正眼压呈正相关性（r=0.66, P＜0.001; r=0.69, P＜0.001）,IOP与BIOP呈高度正相关性（r=0.92, P＜0.001）。IOP与NCT眼压、Pentacam校 正眼压、BIOP的95%一致性界限与最大差值绝对值分别为（-2.8~4.3 mmHg, 3.8 mmHg）、（-3.1~4.5 mmHg, 4.1 mmHg）、（-1.46~1.97 mmHg, 1.9 mmHg）,BIOP与NCT眼压、Pentacam校正眼压的95%一 致性界限与最大差值绝对值分别为（-3.6~4.6 mmHg, 4.2 mmHg）、（-3.0~3.9 mmHg, 3.4 mmHg）。中 央角膜厚度：Corvis ST与A超、Lenstar、Pentacam所测量的中央角膜厚度值在组间比较差异有统计 学意义（F=2.67, P=0.046）,其中Corvis ST与A超的差异有统计学意义（P=0.017）。Corvis ST与A超、 Lenstar、Pentacam所测量的中央角膜厚度值存在着高度正相关性（r=0.96, P＜0.001; r=0.98, P＜0.001; r=0.98, P＜0.001）。Corvis ST与A超、Lenstar、Pentacam对中央角膜厚度的测量值的95%一致性界限 与最大差值绝对值分别为（-5.9~24.3 μm, 23 μm）、（-6.4~18.7 μm, 18 μm）、（-10.7~12 μm, 11 μm）。结 论：Corvis ST的眼压测量值与NCT、Pentacam不可相互替代,并且Corvis ST的BIOP更接近真实眼压; Corvis ST的CCT测量值与A超、Lenstar不可相互替代,与Pentacam可相互替代。     

中国近视患者的角膜厚度与屈光度关系的研究

目的　了解我国近视眼患者角膜厚度 ,及其与屈光度的相互关系 ,并给出由屈光度预测角膜厚度的回归方程 ,为准分子激光原位角膜磨镶术 (LASIK)手术设计提供参考依据。方法　应用OrbscanⅡ眼前节系统对 45 9例近视眼患者角膜厚度进行检测 ,包括角膜中央直径为 2mm及角膜中周部上方、颞上、颞侧、颞下、下方、鼻下、鼻侧、鼻上、上方 9个直径为 2mm的测量区 (距视轴3mm)的平均角膜厚度 ;屈光度由 -0 5D至 -2 3 5D不等 ;并对各方位角膜厚度与屈光度作直线相关 ,如有相关性则进行回归分析。结果　中国近视眼患者角膜厚度以中央区最薄 ,鼻上方最厚 ,近视眼患者角膜最薄点多位于颞下方 ( 5 2 72 % ) ;颞下及颞侧角膜厚度与屈光度呈线性负相关 (相关系数r分别为 -0 117、 -0 10 7,P <0 0 5 0 ) ;其它部位与屈光度无相关关系 ;角膜厚度彩色地形图中均为圆形最多 ,依次为椭圆形、偏心圆形、偏心椭圆形。结论　中国近视眼患者角膜厚度的改变多位于颞下及颞侧 ,且角膜厚度随近视度数增加有变薄倾向 ;而最薄点、中央区、颞上、鼻下、鼻侧、鼻上、上方、下方角膜厚度与近视度数增加无关 ;OrbscanⅡ眼前节系统能了解角膜厚度分布情况 ,在角膜屈光手术中具有广泛应用前景     

Corvis ST测量青光眼患者眼压及中央角膜厚度的准确性研究

目的：评估角膜生物力学分析仪（CST）测量青光眼患者眼压（IOP）及中央角膜厚度（CCT）的准确性,研究角膜生物力学参数对IOP的影响。方法：描述性研究。28 例（56 眼）明确诊断为青光眼的患者,由同一位高年资医师分别用CST及Goldmann压平眼压计（GAT）测量其IOP,采用CST和IOLMaster测量CCT。不同设备测量值比较采用配对t 检验,相关性分析采用非参数Spearman检验,一致性验证采用Bland-Altman检验。结果：CST与GAT测得IOP平均值分别为（19.5±12.0）mmHg（1 mmHg=0.133 kPa）、 （20.9±8.8）mmHg,差异无统计学意义;CST与IOLMaster测得CCT平均值分别为（544±40）μm、 （538±40）μm,差异无统计学意义。CST与GAT测得的IOP具有高度相关性（ρ=0.837,P ＜0.001）,CST与IOLMaster测得的CCT具有高度相关性（ρ=0.958,P ＜0.001）。GAT与CST测得的IOP差值均值为（1.3±5.4）mmHg,95%的一致性界限为（-9.3,12.0）mmHg,IOLMaster与CST测得的CCT差 值均值为（6±10）μm,95%的一致性界限为（-26,15）μm。结论：CST可获得精确的IOP与CCT,但CST测量的IOP稍低于GAT,在青光眼的诊治中不能完全替代GAT.     

三种仪器测量中央角膜厚度的对比研究

目的探讨Pentacam眼前段分析仪、Orbscan-Ⅱ眼前节分析仪与A超角膜厚度测量仪三种仪器测量中央角膜厚度的差异。方法126例（252眼）欲做准分子激光手术的近视患者分别用Pentacam眼前段分析仪、A超角膜测厚仪、Orbscan-Ⅱ三种仪器测量中央角膜厚度。用SPSS11.0统计学软件对不同方法测量的结果进行配对t检验,并作Pearson相关性分析。结果三种仪器所测得中央角膜厚度测量结果分别为：Pentacam（546.3±33.6）μm,Orbscan-Ⅱ（550.5±38.5）μm,A超角膜测厚仪（538.6±35.4）μm。三种检查仪测量结果两两之间差异均有统计学意义（P=0.000）,且有高度的相关性。A超角膜测厚仪比其他两种测量仪测量所得的中央角膜厚度要薄。再以A超角膜测厚仪测量的角膜厚度为基准把患者分为三组：〈520μm,≥520μm且〈580μm,≥580μm,对三种仪器测量的结果进一步对比分析。第一组角膜厚度〈520μm,71只眼,A超角膜测厚仪测量结果比Pantacam和Orbscan-Ⅱ测量结果要薄,差异均有统计学意义（P=0.000,P =0.000）。而Pentacam与Orbscan-Ⅱ的测量值差异无统计学意义（P=0.143）。第二组角膜厚度≥520μm且〈580μm,154只眼,Orbscan-Ⅱ测量结果比Pantacam较厚,Pantacam比A超角膜测厚仪测量结果要厚,差异均有统计学意义（P=0.000,P=0.000）。第三组角膜厚度≥580μm,27只眼,Orbscan-Ⅱ测量结果比Pantacam和A超角膜测厚仪测量结果要厚,差异均有统计学意义（P=0.000,P=0.000）,而Pentacam与A超角膜测厚仪的测量值差异无统计学意义（P=0.747）。结论在对中央角膜厚度的测量中,Pentacam、Orbscan-Ⅱ与A超角膜测厚仪三种仪器之间是不能互相替换的。     

角膜生物力学眼压分析仪Corvis ST测量值的重复性与一致性研究

目的分析一种新型角膜生物力学眼压分析仪Corvis ST测量角膜动态过程中相关参数重复性及一致性,以评估其临床应用的可靠性。方法前瞻性病例研究。选取47例行准分子激光屈光手术的患者（右眼）,由同一检查者应用Corvis ST对被检眼进行检查;其中34例同时进行了眼反应分析仪（ORA）、非接触式眼压计（NCT）及Pentacam眼前节分析仪检查,并进行一致性对比。采用组内相关系数（ICC）和Cronbach′s Alpha系数分析Corvis ST测量结果的重复性,采用Bland-Altman分析一致性,采用Pearson线性相关分析Corvis ST测量的生物力学参数与ORA测量的参数、Pentacam测量的角膜中央厚度（CCTst和CCTp）的相关性,采用配对t检验分析差异性。结果Corvis ST测量的角膜动态过程的变化值中1st A-time、2nd A-time、Vout、HC-DA、IOPst和CCTst的 Cranbach′s a系数均在0.8以上,组内相关系数也均≥0.8,重复性较好。IOPst与IOPg、IOPcc和IOPnct,CCTst与CCTp均具有较好的一致性,95%的一致性界限分别为（-2.62,4.91）mmHg、（-3.04,6.22）mmHg、（-2.29,4.44）mmHg和（-15.57,13.59）μm。IOPst与IOPg、IOPnct,CCTst与CCTp具有较高相关性（r=0.774、0.791、0.981,P＜0.05）。IOPst与IOPg、IOPcc、IOPnct差异有统计学意义,（t=-3.464、-3.922、-3.661,P＜0.05）,CCTst与CCTp差异无统计学意义（t=0.778,P＞0.05）。1st A-time、Vout和HC-DA与角膜阻力因子（CRF）、角膜滞后量（CH）均有较高相关性（r=0.721、0.520、-0.545、-0.354、-0.596、-0.391,P＜0.05）。结论该型角膜生物力学眼压仪在测量角膜生物动态过程中部分参数显示出较好的重复性,IOPst、CCTst与ORA和Pentacam具有较好的一致性。     

干眼症患者角膜厚度的测量研究

目的探讨正常人和干眼症患者角膜厚度的差异.方法应用Orbscan角膜地形图系统检测正常人31例(52只眼)及干眼症患者34例(57只眼)的角膜厚度,对其九个位点的角膜厚度和彩色角膜厚度图形态等变化进行观察.结果干眼症患者的九个位点角膜厚度均明显薄于正常眼,平均减少0.033mm.两组中央区均为最薄区,分别为(0.549±0.027)mm与(0.510±0.022)mm.正常组鼻侧为最厚,而干眼组鼻上方为最厚,分别为(0.644±0.039)mm与(0.613±0.037)mm.正常组与干眼症组彩色厚度图图形比较,离心圆形在正常组与干眼症组分别为5.8%和19.3%,两者间有统计学意义(P=0.035).结论干眼症患者的角膜厚度明显薄于正常眼,厚度图形向离心圆形方向改变.     

Influence of corneal biomechanical properties on intraocular pressure measurement: quantitative analysis

PURPOSE: To understand and quantify intraocular pressure (IOP) measurement errors introduced by corneal variables during applanation tonometry using a cornea biomechanical model. SETTING: Department of Ophthalmology, Biomedical Engineering Center, The Ohio State University, Columbus, Ohio, USA. METHODS: The model assumed an overall resultant pressure that was based on the summation of the applanation pressure, the true IOP, and the surface tension caused by the tear film to determine the final deformation of the corneal apex during IOP measurement. Corneal resistance was varied according to the cornea's biomechanical properties, thickness, and curvature, and the effect of each variable on the accuracy of IOP tonometry readings was examined quantitatively. RESULTS: The model demonstrated that tonometry readings do not always reflect true IOP values. They deviate when corneal thickness, curvature, or biomechanical properties vary from normal values. Based on the model, predicted IOP readings have a 2.87 mm Hg range resulting from the variation in the corneal thickness in the normal population and a 1.76 mm Hg range from the variation in the corneal radius of curvature. Considering that Young's modulus of the corneal varies from 0.1 to 0.9 MPa in the normal population, the model predicts tonometry IOP readings will have a range of 17.26 mm Hg because of the variation in this corneal biomechanical parameter alone. CONCLUSIONS: The simulation based on the model demonstrated quantitatively that variations in each corneal variable cause errors in tonometry IOP readings. The simulation results indicate that differences in corneal biomechanics across individuals may have greater impact on IOP measurement errors than corneal thickness or curvature.     

Repeatability of intraocular pressure and corneal biomechanical properties measurements by the ocular response analyser

BACKGROUND: The Ocular Response Analyser (ORA, Reichert Ophthalmic Instruments) is a non-contact applanation tonometer, providing two measures of intraocular pressure (IOP) - IOPg which represents a Goldmann equivalent IOP measure and IOPcc, representing a measure of IOP independent of corneal effects. In addition, the device provides two measures believed to represent corneal biomechanical properties: corneal hysteresis (CH) and corneal resistance factor (CRF). The aim of this study was to assess the repeatability of these measurements. PATIENTS AND METHODS: One randomly chosen eye from 49 healthy volunteers was measured four times consecutively with the ORA prior to Goldmann applanation tonometry (GAT). The repeatability coefficient (RC), the coefficient of variation (CV) and the intraclass correlation coefficient (ICC) were calculated as a measure of intrasession repeatability. RESULTS: CH was the most variable and IOPg the most repeatable measure, with an RC of 2.61 and 1.97, respectively, and ICC of 0.86 and 0.92, respectively. CV ranged between 5.73 % for IOPg and 12.38 % for CH. ORA IOP measurements were higher than GAT (IOPcc = 17.43 +/- 3.23; IOPg = 17.53 +/- 3.0; GAT = 15.75 +/- 2.77 mmHg). CONCLUSIONS: ORA measurements show good short-term repeatability in normal volunteers. Thus, this device appears to be applicable in clinical practice.     

Evaluation of the influence of corneal biomechanical properties on intraocular pressure measurements using the ocular response analyzer

PURPOSE: The Ocular Response Analyzer (ORA) proposes to measure corneal biomechanical properties in vivo by monitoring and analyzing the corneal behavior when this structure is submitted to a force induced by an air jet. The purpose of this study was to evaluate the relationship between corneal biomechanical properties and corneal-compensated intraocular pressure (IOPCC) measurements as obtained by the ORA and Goldmann applanation tonometry (GAT) measurements. DESIGN: Observational clinical study. METHODS: The study included 153 eyes of 78 subjects. All subjects underwent IOP evaluation with the ORA and GAT, and also measurements of central corneal thickness (CCT), corneal curvature, and axial length. Univariable and multivariable regression analysis were used to evaluate the associations between IOP (as measured with GAT and ORA) and CCT, corneal curvature, axial length, and age. Bland and Altman plots were used to evaluate the agreement between IOP measurements obtained by GAT and ORA. RESULTS: GAT IOP measurements were significantly associated with CCT (P=0.001) and corneal curvature (P<0.001), whereas ORA IOPCC measurements were not associated with any of the ocular variables. The difference between GAT and IOPCC measurements was significantly influenced by corneal thickness. Patients with thicker corneas tended to have higher GAT IOP measurements compared with IOPCC, whereas in patients with thin corneas, GAT IOP measurements tended to be lower than IOPCC. CONCLUSIONS: ORA IOPCC measurements seem to provide an estimate of IOP that is less influenced by corneal properties than those provided by GAT.     

Ganglion cells apoptosis in diabetic rats as early prediction of glaucoma: a study of Brn3b gene expression and association with change of quantity of NO, caspase-3, NF-κB, and TNF-α

AIM: To find a new concept to show whether or not apoptosis of retinal ganglion cells (RGCs) can be determined in the histology of acute hyperglycemia in the role of expressed Brn3b gene related to nitric oxide (NO), caspase-3, nuclear factor kappa-B (NF-κB), and tumor necrosis factor-α (TNF-α) as an early predictor of primary open angle glaucoma (POAG) eyes and their associations.METHODS: Experimental in vivo study was carried out using adult male, white Sprague-Dawley rats aged ≥2mo, weighing 150-200 g. The animals were divided into two groups, one group receiving intraperitoneal injection of streptozotociz 50 mg/kg in 0.01 mol/L citric buffer and pH 4.5 and a comparison made with the control group. Retinal tissue was divided into two parts (both experimental and control groups respectively): a) right retina for immunohistochemistry (IHC; caspase-3 and TNF-α); b) left retina was divided into two parts for the purpose of real-time polymerase chain reaction (PCR) test (RNA extraction for Brn3b gene expression analysis) and ELISA test (NO and NF-κB).RESULTS: The experimental group showed a decrease in Brn3b gene expression compared to the control group (1.3-fold lower in 2nd month; 1.1-fold lower in 4th month and 2.5-fold lower in 6th month). However, there was a decrease of NO, caspase-3, and an increase of NF-κB and TNF-α quantity.CONCLUSION: The expression of mRNA Brn3b gene is inversely proportional to apoptosis in RGCs. The quantity of NO, caspase-3, NF-κB and TNF-α is influential in expression of Brn3b in RGCs caused by hyperglycemia in diabetic rats.     

Study of corneal biomechanical properties in patients with childhood glaucoma

AIM: To observe and characterize imaging features of macular and optic disc areas in less than 60-year-old patients with early primary open angle glaucoma (POAG) by optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA), and to evaluate the diagnostic value of OCT and OCTA. METHODS: Totally 15 patients (23 eyes) with early POAG as observation group and 30 health people (30 eyes) as normal control group were enrolled in this cross-sectional study. OCTA-based superficial macula vessel density, superficial macula perfusion density, superficial optic disc vessel density, superficial optic disc perfusion density and spectral domain OCT (SD-OCT)-based macular area thickness, GCC thickness and RNFL thickness were measured in the two groups. Independent t-test and receiver operating characteristic curve were used for analysis. Area under the receiver operating characteristic curves (AUROC) were used to measure the diagnostic utility. RESULTS: Among all the parameters, the optimal diagnostic utility parameter was the superficial vessel density in the macular area (except the center of the macula), and the AUROC reached 0.98. The diagnostic utility of macular area perfusion density (except the center of the macula) was similar to that of superficial vessel density in the macular area, and the AUROC was above 0.97. Followed by the diagnostic utility of vessel density in the optic disc area, the best parameter was the inner ring of the vessel density, and its AUROC reached 0.97. The diagnostic utility of perfusion density in the optic disc area was slightly lower than that of vessel density in the optic disc area. The best parameter was the central optic disc perfusion density, and its AUROC was 0.95. The SD-OCT-based diagnostic utility parameters were generally lower than that mentioned above, the top three parameters were the inferior RNFL thickness (AUROC=0.919), the superior GCC thickness (AUROC=0.919) and the inferior GCC thickness (AUROC=0.908). CONCLUSION: The OCT-based diagnostic utility parameters are generally lower than the OCTA-based diagnostic utility parameters. OCTA has an important clinical application value in diagnosis and evaluation for less than 60-year-old patients with early POAG.     

中央角膜厚度对常用眼压计测量值的影响

眼压在青光眼和其他眼科疾病的诊断和疗效评估中起着很重要的作用。已经有不少研究发现,各种眼压计的测量值都受中央角膜厚度的影响。不同的眼压计所受影响不同。本文对中央角膜厚度和不同眼压计测量值的关系进行综述。