Diagnostic capability of optical coherence tomography in evaluating the degree of glaucomatous retinal nerve fiber damage

PURPOSE: To evaluate the role and ability of optical coherence tomography (OCT) to detect differences in peripapillary retinal nerve fiber layer (RNFL) thickness between normal and glaucomatous eyes and also between different severities of glaucoma. METHOD: This cross-sectional observational study included 160 eyes of 160 healthy subjects and 134 eyes of 134 patients with primary open-angle glaucoma (POAG). Peripapillary RNFL thickness was measured on OCT using the fast RNFL thickness protocol. The RNFL thickness parameters used for evaluation included average RNFL thickness and inferior, superior, nasal, and temporal RNFL thickness. The glaucomatous eyes were subdivided into three subgroups on the basis of visual field defects and a fourth subgroup of eyes blinded by glaucoma. RNFL thickness parameters were compared among the normal eyes and the glaucoma subgroups. Correlation of global visual field indices with RNFL thickness parameters was also performed. RESULTS: The average RNFL in control subjects, early glaucoma, moderate glaucoma, severe glaucoma, and blind glaucoma were 102.30 +/- 10.34, 77.68 +/- 15.7, 66.07 +/- 15.5, 53.65 +/- 14.2, and 44.93 +/- 4.95 microm, respectively. There was a significant difference in all RNFL thickness parameters between normal and all glaucoma subgroups (P < 0.001). Average and inferior RNFL thicknesses showed the highest area under the receiver operating characteristic curve, with 0.905 and 0.862 for normal versus early glaucoma, 0.705 and 0.722 for early versus moderate glaucoma, 0.737 and 0.717 for moderate versus severe glaucoma, and 0.635 and 0.584 for severe versus blind glaucoma. Both mean deviation (MD) and corrected pattern standard deviation (CPSD) showed a significant correlation with all the RNFL thickness parameters in eyes with glaucoma (P < 0.001). CONCLUSIONS: RNFL thickness measured on OCT may serve as useful adjuncts in accurately and more objectively distinguishing normal from glaucomatous eyes, even in the early stages of glaucoma and may help to differentiate various severities of glaucoma. Average and inferior RNFL thicknesses are among the most efficient parameters for distinguishing such a differentiation. RNFL thicknesses in eyes blinded by glaucoma provide an estimate of the component of the RNFL thickness, which is not related to visual function.     

Optic nerve head topographic measurements and retinal nerve fiber layer thickness in physiologic large cups

PURPOSE: To evaluate the parameters of optic nerve head (ONH) and retinal nerve fiber layer (RNFL) in patients with large cup/disc ratio (CDR) and normal neuroretinal rim configuration who have normal perimetry (physiologic large cups, LC) and to compare these parameters with those of the normal and early glaucoma patients. METHODS: Using Heidelberg retinal tomography (HRT) and optical coherence tomography (OCT), 30 patients with LC, 29 normal subjects, and 31 early glaucoma patients were examined. One eye from each subject was randomly selected. RESULTS: Significant differences between LC and glaucomatous eyes (GE) were found in parameters indicating loss of nerve fibers, such as rim area, rim volume, and mean RNFL thickness. However, there was no difference between LC and normal eyes (NE) in RNFL thickness, rim area, and rim volume. LC was able to be defined as a normal central excavation with a large disc and large CDR with a normal rim area. CONCLUSIONS: HRT ONH parameters and RNFL thickness obtained with OCT may be useful for differentiating between glaucoma and LC eyes.     

频域OCT视盘形态及神经纤维层厚度参数在青光眼诊断中的作用μ

背景青光眼是一种可引起视神经结构改变,继而导致不可逆视功能损害的一类疾病。光学相干断层扫描（OCT）通过对视盘形态以及神经纤维层的检测,有助于青光眼的早期诊断。目的探讨频域OCT视盘形态及神经纤维层厚度各参数在青光眼诊断中的作用。方法非干预性、横断面研究。应用频域RTVue OCT测量62例正常人和67例青光眼患者的视盘参数,以及视网膜各区域的神经纤维层厚度。用受试者工作特性曲线下面积（ROC）评价OCT每个检测参数区分正常眼与青光眼的能力大小。结果各型青光眼组患者的年龄明显大于正常组,各型青光眼组视野平均缺损（MD）和视野模式标准化差（PSD）值均明显大于正常组,差异均有统计学意义（P〈0．01）。正常组、青光眼组、开角型青光眼组和闭角型青光眼组间视盘面积的总体差异均无统计学意义（P=0．101、0．741、0．652）;正常人平均视网膜神经纤维层厚度为（109．758±9．095）μm,青光眼患者为（79．539±18．986）μm,明显低于正常人（P〈0．01）。在视盘周围8个神经纤维层区域中,正常人最厚的区域在颞下方和颞上方,分别为（150．109±18．007）μm和（146．105±15．529）μm,而青光眼患者最厚处在颞上方和颞下方,分别为（104．354±27．641）μm和（102．436±32．243）μm,但均较正常参数减小。正常人和青光眼患者鼻侧和颞侧视网膜神经纤维层厚度均较薄。视盘参数中,各型青光眼诊断效能最高的是盘沿容积和垂直杯盘比,二者的ROC值在总青光眼患者中分别为0．850和0．840,其特异性在80％时的敏感性分别为73．1％和76．1％,在开角型青光眼患者中分别为0．841和0．849,其特异性在80％时的敏感性分别为73．0％和81．1％,在闭角型青光眼患者中分别为0．862和0．830,其特异性在80％时的敏感性分别为73．3％和70．O％。视网膜神经纤维层厚度各参数中,诊断效能最高的是平均神经纤维层厚度,其ROC值在总青光眼、开角型青光眼、闭角型青光眼中分别为0．925、0．910和0．942,其特异性在80％时的敏感性分别为89．6％、89．2％和90．0％。视盘周围8个神经纤维层区域中,诊断效能最高的是IT区域,诊断效能最低的是TU和TL区域。结论RTVueOCT具有很好地区别正常人和青光眼患者的能力,在青光眼诊断方面是一个较实用的工具。     

Comparison of optical coherence tomography and scanning laser polarimetry in glaucoma, ocular hypertension, and suspected glaucoma.

BACKGROUND AND OBJECTIVE: To compare the performance of the newest generation optical coherence topography (OCT) and scanning laser polarimetry with variable corneal compensation (SLP-VCC) in eyes with glaucoma, ocular hypertension, and suspected glaucoma. PATIENTS AND METHODS: One eye each of 84 patients (30 with glaucoma, 26 with suspected glaucoma, and 28 with ocular hypertension) was included in the study. Retinal nerve fiber layer (RNFL) thickness was measured with both technologies and thickness parameters were compared in the three groups of eyes. The correspondence of RNFL thickness measurements with visual field function was also studied. RESULTS: Average OCT-RNFL thickness was found to have a statistically significant difference between patients with glaucoma and either suspected glaucoma or ocular hypertension. A statistically significant correlation between the average RNFL thicknesses measured by the two different technologies was shown only in the glaucoma group. A significant correlation with visual field mean deviation was found for superior average RNFL thickness as measured by SLP and for nerve fiber indicator and average and inferior average RNFL thickness as measured by OCT in glaucomatous eyes. Regression analysis indicated nerve fiber indicator to be the most valuable factor in predicting mean deviation. CONCLUSION: RNFL thickness measurements obtained with OCT and SLP-VCC correlate well only in eyes with more advanced glaucomatous damage. The nerve fiber indicator parameter derived by SLP correlated best with mean deviation.     

Development of a novel reference plane for the Heidelberg retina tomograph with optical coherence tomography measurements

PURPOSE: To develop an ideal reference plane for the Heidelberg Retina Tomograph (HRT) with the assistance of optical coherence tomography (OCT) measurements of the mean retinal nerve fiber layer (RNFL) thickness. PATIENTS AND METHODS: The mean RNFL thickness was measured with OCT in eyes with early glaucoma (n = 50) and age-matched normal eyes (n = 40) at a circle as close as possible to the disc margin without touching it. Glaucomatous eyes were enrolled from chronic open-angle glaucoma patients with reproducible glaucomatous visual field defects with standard automated perimetry. One eye of each patient was randomly selected. A new reference plane was defined as located posteriorly from the mean height of the contour line by the amount of mean RNFL thickness measured with the OCT. Receiver-operating characteristic (ROC) curves were generated to compare the ability of parameters obtained with the conventional and the new reference plane to differentiate glaucomatous eyes from normal eyes. The same analysis was performed for early glaucomatous eyes with myopic refractive errors (n = 25). RESULTS: The areas under the ROC curves (AUCs) were greater for rim area, rim area/disc area, and rim volume with the new reference plane compared with those with the conventional reference plane, but they were not significantly different. When the same analysis was performed for myopic glaucomatous eyes, the AUCs for rim area, rim area/disc area, and rim volume with the new reference plane were greater than those with the conventional reference plane ( = 0.002, 0.010, and 0.034, respectively). CONCLUSION: A novel reference plane for the HRT defined by OCT measurements may improve the ability of the HRT to detect early glaucoma, especially in eyes with tilted discs.     

Comparison of glaucomatous parameters in normal, ocular hypertensive and glaucomatous eyes using optical coherence tomography 3000

This study was performed to evaluate optic disc appearance, retinal nerve fiber layer (RNFL) thickness, and macular thickness in normal, ocular hypertensive (OHT) and glaucomatous eyes using optical coherence tomography (OCT) 3000. One hundred fifty-eight eyes of 167 consecutive subjects were enrolled: 60 normal, 53 OHT, and 54 glaucomatous. OCT topographic parameters of cup diameter, cup area, rim area, and cup/disc area ratio were significantly less in OHT eyes than in normal eyes and were significantly less in glaucomatous eyes than in normal and OHT eyes. RNFL was significantly thinner in OHT eyes than in normal eyes in the inferior quadrant, and in glaucomatous eyes than in OHT and normal eyes in the mean and for all four quadrants. Macular thickness was significantly thinner in glaucomatous eyes than in OHT and normal eyes throughout all subdivisions. Optic disc parameters, and RNFL and macular thickness measurements made with OCT may be useful in the clinical assessment of glaucoma.     

Usefulness of optical coherence tomography parameters of the optic disc and the retinal nerve fiber layer to differentiate glaucomatous, ocular hypertensive, and normal eyes

PURPOSE: To assess Stratus optical coherence tomography (OCT) original parameters for identifying glaucomatous damage and to evaluate differences among glaucomatous, ocular hypertensive, and normal eyes. DESIGN: Cross-sectional prospective study. SUBJECTS AND METHODS: The study was conducted at 2 centers. The study population consisted of 55 normal individuals, 95 patients with ocular hypertension (OHT), and 79 patients with glaucoma. Retinal nerve fiber layer (RNFL) and optic nerve head OCT protocols were used to evaluate all study participants. Measurements taken were RNFL thickness, several ratios, RNFL asymmetry between both eyes, rim volume, rim width, disc area, cup area, rim area, cup/disc (C/D) area ratio, and horizontal and vertical C/D ratios. The main outcome measures were the differences in OCT parameters among groups and the areas under the receiver operating characteristic curves (AROC). RESULTS: Mean RNFL thickness around the disc, and superior and inferior RNFL thickness, were significantly thinner in glaucomatous eyes than in OHT or normal eyes (P<0.001). Rim parameters were significantly smaller in glaucomatous eyes than in normal (P<0.001) and OHT eyes (P=0.01). C/D ratios were significantly greater in glaucomatous eyes than in OHT (P<0.001) and normal (P<0.001) eyes. Significant differences were found between normal and OHT eyes in 7 disc parameters. No difference was found among groups in parameters describing RNFL asymmetry between both eyes. The AROC curves of the other RNFL and disk parameters ranged from 0.741 to 0.85. CONCLUSIONS: Almost all RNFL and disc parameters showed significant differences and discriminated between glaucomatous and normal eyes. There were significant differences in some optic nerve parameters, but no RNFL parameters, between normal and OHT eyes.     

Discrimination between normal and glaucomatous eyes using Stratus optical coherence tomography in Taiwan Chinese subjects

Background We differentiated between normal and glaucomatous eyes in the Taiwan Chinese population based solely on the quantitative assessment of summary data reports from Stratus optical coherence tomography (OCT) by comparing their area under the receiver operating characteristic (ROC) curve.Methods One randomly selected eye from each of the 62 patients with early glaucomatous damage (mean deviation –2.8 ± 1.8 dB) and from each of the 62 age- and sex-matched normal individuals were included in the study. Measurements of glaucoma variables (retinal nerve fiber layer thickness and optic nerve head analysis results) were obtained by Stratus OCT. Twenty-one OCT parameters were included in a linear discriminant analysis (LDA) using forward selection and backward elimination to determine the best combination of parameters for discriminating between glaucomatous and healthy eyes based on ROC curve area.Results The average RNFL thickness was the best individual parameter for differentiating between normal eyes and glaucomatous eyes (ROC curve area 0.793). The maximum area under the ROC curve of six input parameters (average RNFL thickness; 10, 11, and 12 oclock segment thicknesses; cup area; and vertical integrated rim area) generated by the forward selection method was 0.881. Whereas the maximum area under the ROC curve of 15 input parameters (average RNFL thickness; 1, 3, 4, 6, 8–10, 12 oclock segment thicknesses; vertical integrated rim area; horizontal integrated rim area; disc area; cup to disc area ratio; cup to disc horizontal ratio; and cup to disc vertical ratio) generated by backward elimination method was 0.929.Conclusions The performance of individual parameters obtained from Stratus OCT is fairly reliable for differentiating the early glaucomatous eyes from normal eyes. However, the discriminant power increases when LDA with forward selection and backward elimination methods is applied.     

OCT测量视网膜神经纤维层和黄斑厚度在青光眼早期诊断中的意义

目的应用光学相干断层成像术（optical coherence tomography，OCT）测量青光眼患者的视网膜神经纤维层（retinal nerve fiber layer，RNFL）厚度和黄斑厚度，比较两者在青光眼早期诊断中的作用。方法应用Stratus OCT测量62例（101眼）正常人和41例（64眼）青光眼患者的RNFL厚度和黄斑厚度，比较正常人和青光眼患者之间．正常人和早期青光眼患者之间上、下、鼻、颞四个象限与平均RNFL厚度、黄斑区内外环各象限厚度和总黄斑体积等参数有无统计学差异：用受试者工作特征曲线下面积（area under the receive operating characteristi ccurve，AROC）评价各个参数在青光眼早期诊断中的作用。结果青光眼患者各象限、平均RNFL厚度和各分区黄斑厚度、总黄斑体积均比正常人减少．差异有显著性（P=0．014—0．000），视乳头旁平均RNFL的AROC最大（0．961），其次为下方RNFL（0．928）和上方RNFL（0．924）。黄斑下方外环区AROC最大（0．876）。早期青光眼患者各象限、平均RNFL厚度和黄斑外环各分区、总黄斑体积较正常人减少，差异有显著性（P=0．021～0．000），而黄斑内环各区与正常人差异无显著性。视乳头旁平均RNFL的AROC最大（0．877），其次为上方RNFL（0．783）和下方RNFL（0．767）。黄斑下方外环区AROC最大（0．728）。结论测量RNFL厚度较测量黄斑厚度具有更强的青光眼早期诊断价值。黄斑厚度测量为青光眼的早期诊断提供了一种新的手段。     

Comparison of confocal scanning laser ophthalmoscopy, scanning laser polarimetry and optical coherence tomography to discriminate ocular hypertension and glaucoma at an early stage

Background The aim was to compare the ability of confocal scanning laser ophthalmoscopy (CSLO), scanning laser polarimetry (SLP), and optical coherence tomography (OCT) to discriminate eyes with ocular hypertension (OHT), glaucoma-suspect eyes (GS) or early glaucomatous eyes (EG) from normal eyes. Methods Ocular hypertension, GS, and EG were defined as normal disc with intraocular pressure >21 mmHg, glaucomatous disc without visual field loss, and glaucomatous disc accompanying the early glaucomatous visual filed loss respectively. Ninety-three normal eyes, 26 OHT, 55 GS, and 67 EG were enrolled. Optic disc configuration was analyzed by CSLO (version 3.04), whereas retinal nerve fiber layer thickness was analyzed by SLP (GDx-VCC; version 5.3.2) and OCT-1 (version A6X1) in each individual. The measurements were compared in the four groups of patients. Receiver operating characteristic curve (ROC) and area under the curve (AUC) discriminating OHT, GS or EG from normal eyes were compared for the three instruments. Results Most parameters in GS and EG eyes showed significant differences compared with normal eyes. However, there were few significant differences between normal and OHT eyes. No significant differences were observed in AUCs between SLP and OCT. In EG eyes, the greatest AUC parameter in OCT (inferior—120; 0.932) had a higher AUC than that in CSLO (vertical cup/disc ratio; 0.845; P=0.017). In GS, the greatest AUC parameter in OCT (average retinal nerve fiber layer [RNFL] thickness; 0.869; P=0.002) and SLP (nerve fiber indicator [NFI]; 0.875; P=0.002) had higher AUC than that in CSLO (vertical cup/disc ratio; 0.720). Conclusions Three instruments were useful in identifying GS and EG eyes. For glaucomatous eyes with or without early visual field defects, SLP and OCT performed similarly or had better discriminating abilities compared with CSLO.     

频域OCT检测视乳头形态及视网膜神经纤维层厚度在青光眼诊断中的作用

目的 探讨频域相干光断层扫描(OCT)检测视乳头形态及视网膜神经纤维层(RNFL)厚度在青光眼诊断中的作用.方法 为非干预性、观察性研究.应用RTVue OCT检测60例正常人和97例青光眼患者的视乳头各参数,以及平均和各个区域的RNFL厚度.采用单因素方差分析对以上各参数组间进行比较.用受试者工作特性曲线下面积(AUC)和特异性≥80%的敏感性来评价每一个检测参数区分正常与各期青光眼的能力大小.结果 除视乳头面积外,正常人和各期青光眼患者各参数测量值之间差异均有统计学意义(F=1.024,P=0.596;F=36.519,54.464,27.659,36.176,20.562,63.833,30.031, 54.652,98.146,78.705,99.839,43.728,75.720,45.709,39.380, 33.590,66.887,78.335,45.485;P=0.000).其中,平均RNFL厚度正常人为109.950μm,早期青光眼患者为93.313 μm,中期青光眼患者为80.374μm,晚期青光眼患者为65.570 μm.在视乳头周围8个RNFL区域中,正常人最厚的为颞下150.066μm和颞上146.285μm.各期青光眼患者最厚的均为颞上,分别为早期108.569 μm,中期103.420μm,晚期88.708μm,其次为颞下,分别为早期108.201μm,中期102.830 μm,晚期86.369 μm.而鼻侧(NU+NL)和颞侧(TU+TL)无论在正常人还是青光眼患者中均较薄.在视乳头形态各参数中,各期青光眼诊断效能最高的均为垂直杯盘比,其AUC值在早、中、晚期青光眼患者中分别为0.762,0.946和0.988,它们特异性在80%时的敏感性分别为62.2%,76.5%和99.2%.在RNFL厚度参数中,早期青光眼诊断效能最高的是颞上区域RNFL厚度,其AUC值为0.915,特异性在80%时的敏感性为89.5%;中期青光眼诊断效能最高的是下方平均RNFL厚度,其AUC值为0.967,特异性在80%时的敏感性为94.1%;晚期青光眼诊断效能最高的是平均RNFL厚度,其AUC值为0.985,特异性在80%时的敏感性为99.2%.在视乳头周围8个RNFL区域中,诊断效能最高的是颞上区域(ST),其AUC值在早、中、晚期青光眼患者中分别为0.915,0.926和0.966,它们特异性在80%时的敏感性分别为89.5%,88.2%和92.9%.诊断效能较低的是颞侧(TU+TL)和鼻侧(NU+NL).结论 RTVue OCT具有较好的区别正常人和各期青光眼患者的能力,在青光眼诊断方面是一个有用的工具.     

Retinal nerve fibre layer of perimetrically unaffected eyes of glaucoma patients: an optical coherence tomography study

Purpose:  The aim of this study is to evaluate whether optical coherence tomography (StratusOCT) may detect early changes in perimetrically unaffected (PU) fellow eyes of glaucomatous patients by assessing retinal nerve fibre layer (RNFL) thickness parameters.
Methods:  Thirty-seven glaucomatous patients with unilateral field loss and 34 age-matched controls were recruited. In glaucoma patients, PU and perimetrically affected fellow eyes were analysed separately. For each group, mean values (±SD) of RNFL thickness parameters were calculated and comparisons between fellow eyes of glaucoma patients and between healthy and PU eyes of glaucoma patients conducted with paired t -test and Mann–Whitney U -test, respectively. Proportion of clock-hour sectors flagged with probability <5% or <1% was collected and differences between healthy and PU eyes were evaluated on Fisher exact test.
Results:  Global (Average Thickness) and sectoral parameters (Inferior and Nasal Average), Maximum thickness–minimum thickness (Max-min), as well as 2-o'clock (nasal side) and 6-o'clock sectors resulted significantly thinner in PU eyes than in control group. Proportion of eyes with clock-hour position flagged with probability <5% or <1% was not significantly different between healthy and PU eyes.
Conclusion:  Despite a standard automated perimetry within normal limits, the StratusOCT detected both localized and diffuse RNFL thinning in PU eyes of glaucoma patients. These eyes should be considered at risk of developing functional damage over time and consequently require thorough monitoring for detecting any sign of progression.     

Evaluation of scanning resolution on retinal nerve fiber layer measurement using optical coherence tomography in normal and glaucomatous eyes

PURPOSE: To evaluate the effect of varying the scanning resolution of optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) measurement on diagnostic sensitivity and functional correlation in glaucoma. PATIENTS AND METHODS: 314 eyes from 182 subjects including 107 normal eyes, 83 glaucoma suspect eyes, and 124 glaucoma eyes were included in this cross-sectional study. Standard automated perimetry and OCT measurement of RNFL thickness were performed. Each individual underwent two scanning protocols: (1) fast RNFL thickness (3.4) scan (with resolution of 256 scan points) and (2) RNFL thickness (3.4) scan (with resolution of 512 scan points). RNFL thickness was compared among the groups. Diagnostic sensitivity was evaluated with Receiver Operating Characteristic (ROC) Curve. Relationship between RNFL thickness and visual field mean deviation was examined using linear regression analysis. RESULTS: Measured RNFL thickness using fast RNFL thickness (3.4) scan was significantly higher compared with RNFL thickness (3.4) scan in average, superior, nasal and inferior RNFL in all diagnostic groups. Comparing normal and glaucoma groups, RNFL thickness (3.4) scan produced the largest area under the ROC curve (0.912) based on average RNFL thickness. A stronger correlation between average RNFL and visual field mean deviation was found in RNFL thickness (3.4) scan (R = 0.75, R = 0.56). CONCLUSIONS: Higher resolution RNFL scan provides better diagnostic sensitivity in glaucoma detection and a stronger correlation with visual function.     

Evaluation of retinal nerve fiber layer, optic nerve head, and macular thickness measurements for glaucoma detection using optical coherence tomography

PURPOSE: To compare the ability of optical coherence tomography retinal nerve fiber layer (RNFL), optic nerve head, and macular thickness parameters to differentiate between healthy eyes and eyes with glaucomatous visual field loss. DESIGN: Observational case-control study. METHODS: Eighty-eight patients with glaucoma and 78 healthy subjects were included. All patients underwent ONH, RNFL thickness, and macular thickness scans with Stratus OCT during the same visit. ROC curves and sensitivities at fixed specificities were calculated for each parameter. A discriminant analysis was performed to develop a linear discriminant function designed to identify and combine the best parameters. This LDF was subsequently tested on an independent sample consisting of 63 eyes of 63 subjects (27 glaucomatous and 36 healthy individuals) from a different geographic area. RESULTS: No statistically significant difference was found between the areas under the ROC curves (AUC) for the RNFL thickness parameter with the largest AUC (inferior thickness, AUC = 0.91) and the ONH parameter with largest AUC (cup/disk area ratio, AUC = 0.88) (P = .28). The RNFL parameter inferior thickness had a significantly larger AUC than the macular thickness parameter with largest AUC (inferior outer macular thickness, AUC = 0.81) (P = .004). A combination of selected RNFL and ONH parameters resulted in the best classification function for glaucoma detection with an AUC of 0.97 when applied to the independent sample. CONCLUSIONS: RNFL and ONH measurements had the best discriminating performance among the several Stratus OCT parameters. A combination of ONH and RNFL parameters improved the diagnostic accuracy for glaucoma detection using this instrument.     

Retinal nerve fiber layer thickness in normal, ocular hypertensive, and glaucomatous Indian eyes: an optical coherence tomography study

PURPOSE: To determine retinal nerve fiber layer (RNFL) thickness measurements in normal, ocular hypertensive (OHT), and glaucomatous Asian Indian eyes. METHODS: This prospective observational cross-sectional study included patients with OHT, primary open angle glaucoma (POAG), and age-matched normal controls. The global and 4-quadrant average RNFL thickness was measured using the Stratus OCT. The main outcome measures were differences in RNFL thickness measurements between the 3 groups. The discriminating power of each parameter was evaluated by calculating areas under receiver operating characteristic curves (AROCs). RESULTS: Twenty-three eyes of 23 POAG patients, 24 eyes of 24 OHT, and 48 eyes of 48 normal controls were analyzed. The superior, inferior, and global RNFL measurements were significantly thinner in OHTs compared with normals (P=0.031, 0.019, and 0.022, respectively). All 5 RNFL parameters were significantly thinner in the POAG group compared with OHT group (P<0.001). Parameters with largest AROCs for distinguishing glaucoma from OHT were average and inferior average RNFL measurements (0.989 and 0.979, respectively). Inferior and superior RNFL measurements had largest AROCs (0.717 and 0.700, respectively) to distinguish OHT from normal eyes. CONCLUSIONS: Stratus OCT detected significant quantitative differences in RNFL thickness between normal, OHT, and glaucomatous Asian Indian eyes.     

Evaluation of optical coherence tomography and heidelberg retinal tomography parameters in detecting early and moderate glaucoma

PURPOSE: To evaluate the relationship between optic nerve head (ONH) and peripapillary retinal nerve fiber layer (RNFL) parameters by optical coherence tomography (OCT) and confocal scanning laser ophthalmoscopy (Heidelberg retinal tomography; HRT; Heidelberg Engineering, Heidelberg, Germany) in early and moderate glaucoma and to compare several OCT-based automated classifiers with those inbuilt in HRT for detection of glaucomatous damage. METHODS: This cross-sectional study included 60 eyes of 60 patients with glaucoma (30 early and 30 moderate visual field defects) and 60 eyes of 60 healthy subjects. All patients underwent Fast Optic Disc and Fast Peripapillary RNFL scans on the OCT and then HRT evaluation of the ONH during the same visit. Glaucoma variables obtained from OCT and HRT analyses were compared among the groups. Receiver operator characteristic (ROC) curves generated by performing linear discriminant analysis (LDA), artificial neural networks (ANNs), and classification and regression trees (CART) on OCT-based parameters were compared with the Moorfield regression analysis (MRA), R Bathija (RB), and FS Mickelberg (FSM) functions in the HRT, to classify eyes as either glaucomatous or normal. RESULTS: No statistically significant difference was found in the disc area measured by the OCT and HRT analyses within each study group (P > 0.05). The areas under ROC curves were 0.9822 (LDF), 0.9791 (CART), and 0.9383 (ANN) as compared with 0.859 (FSM), 0.842 (RB) and 0.767 (MRA). CONCLUSIONS: OCT-based automated classifiers performed better than HRT classifiers in distinguishing glaucomatous from healthy eyes. Such parameters should be integrated in the OCT to improve its diagnostic abilities.     

傅立叶OCT和海德堡激光眼底扫描仪在开角型青光眼早期诊断中的应用

背景研究表明,视网膜神经纤维层（RNFL）缺损是青光眼早期损害的重要表现,如何准确地定量检测RNFL的厚度变化是青光眼早期诊断及监测青光眼病情进展的关键步骤之一。目的对傅立叶OCT、海德堡激光眼底扫描仪（HRT—Ⅲ）测量青光眼患者的RNFL厚度以及视盘的各项参数进行分析,对二者在青光眼早期诊断中的作用进行临床评价。方法收集可疑开角型青光眼（SOAG）患者26例40眼、原发性开角型青光眼（POAG）患者29例48眼以及正常对照组27例48眼。应用傅立叶OCT、HRT—Ⅲ、Humphrey 750-i型全自动视野计对所有研究对象分别进行视盘面积,视杯面积,杯盘面积比,盘沿面积,盘沿容积,视盘上方、下方、颞侧、鼻侧象限的RNFL厚度等参数测定和视野检查,对不同受检者测得的各项参数进行分析和比较,分别与视野平均缺损值做相关分析,评价不同参数对于青光眼RNFL损伤的诊断价值。结果傅立叶OCT和HTR—Ⅲ检测对正常对照组检查结果均证实RNFL从厚到薄依次为视盘下方、上方、颞侧、鼻侧象限,SOAG组和POAG组RNFL厚度变薄的顺序依次为视盘下方、上方、颞侧、鼻侧象限,各部位厚度改变的差异均有统计学意义（P〈0．05）,SOAG组和POAG组患者盘沿面积、杯盘面积比、视杯面积、盘沿容积与正常对照组比较,差异均有统计学意义（P〈0．05）。对3组患者的检测表明,傅立叶OCT与HTR-Ⅲ检测视盘上方象限、下方象限的测定之间存在着正相关关系（r=0．362、r=0．441、r=0．395,P〈0．05）;2种检查方法所测得3个组视杯容积、视杯面积、盘沿容积、杯盘面积比呈正相关（P〈0．05）。在POAG组中,傅立叶OCT测得视盘参数中的盘沿面积、盘沿容积、视杯容积、杯盘面积比与视野的平均缺损值间的相关系数分别为0．284、0．286、0．340、0．371（P〈0．05）;HRT-Ⅲ测得视盘参数中的盘沿面积、盘沿容积、杯盘面积比与视野的平均缺损值间的相关系数分别为0．339、0．859、0．422（P〈0．05）。结论傅立叶OCT和HRT-Ⅲ检测的视盘参数结果接近,且均与视野的平均缺损值有较好的相关性;所检测杯盘面积比、盘沿面积和视盘上方象限、下方象限的RNFL厚度的改变在青光眼早期诊断中均有重要价值。     

Retinal nerve fiber layer measurement by optical coherence tomography in glaucoma suspects with short-wavelength perimetry abnormalities

PURPOSE: To compare retinal nerve fiber layer (RNFL) measurements in normal and glaucoma subjects with short-wavelength automatic perimetry (SWAP) abnormalities and in chronic primary open-angle glaucoma (CPOAG) patients using optical coherence tomography (OCT). METHODS: Forty-eight eyes of normal subjects, 34 eyes of glaucoma suspects with SWAP abnormalities, and 38 eyes of early CPOAG subjects were recruited. All normal and glaucoma suspects had normal conventional automated perimetry visual field results. All participants underwent full clinical ophthalmologic evaluation followed by OCT RNFL measurements. RESULTS: Compared with normal controls, OCT RNFL thickness was significantly lower in glaucoma suspects with abnormal SWAP (inferotemporal and superotemporal thickness values) and CPOAG patients (average, superior, inferior, inferotemporal, and superotemporal thickness values) (P < 0.01). Some parameters were found to be significantly lower in CPOAG patients than the glaucoma suspects with abnormal SWAP (average, inferior, inferotemporal, and superotemporal thickness values) (P < 0.01). CONCLUSIONS: OCT RNFL measurements appear to correlate well with SWAP abnormalities in glaucoma, and may detect glaucomatous damage earlier than standard conventional automated perimetry. This study suggests that OCT may recognize the earliest evidence of structure alterations in CPOAG.     

The relationship between optical coherence tomography and scanning laser polarimetry measurements in glaucoma

PURPOSE: To investigate the relationship between optical coherence tomography (OCT) and scanning laser polarimetry (SLP) in measuring peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous eyes. METHODS: Fifty glaucomatous eyes were evaluated in this study. Evaluations were analyzed two ways. First, parameters of the Stratus OCT (average thickness, superior/inferior average) and GDx VCC (TSNIT average, nerve fiber indicator (NFI), superior/inferior average) were correlated using the Pearson's correlation coefficient (r). Secondly, comparison (r) of these parameters was completed using the mean deviation (MD) of visual field defect. RESULTS: The following parameters were found to be significantly correlated (P < 0.005). TSNIT average/average thickness (r = 0.673), NFI/average thickness (r = -0.742), superior average (r = 0.841), and inferior average (r = 0.736). In the correlation analysis using the severity of visual field defect, all these parameters had statistically meaningful correlations (P < 0.005). CONCLUSIONS: GDx VCC and Stratus OCT are highly correlated in glaucomatous eyes. Therefore, peripapillary RNFL thickness measured by Stratus OCT and GDx VCC may be equally helpful in the diagnosis of glaucoma.     

Reproducibility of retinal nerve fiber thickness measurements using the stratus OCT in normal and glaucomatous eyes

PURPOSE: To determine the reproducibility of Stratus Optical Coherence Tomography (OCT) retinal nerve fiber layer (RNFL) measurements around the optic nerve in normal and glaucomatous eyes. METHODS: One eye was chosen at random from 88 normal subjects and 59 glaucomatous subjects distributed among mild, moderate, and severe glaucoma, determined by visual field testing. Subjects underwent six RNFL thickness measurements performed by a single operator over a 30-minute period with a brief rest between sessions. Three scans were taken with the high-density Standard RNFL protocol, and three were taken with the Fast RNFL protocol, alternating between scan protocols. RESULTS: Reliability, as measured by intraclass correlation coefficient (ICC), was calculated for the overall mean RNFL thickness and for each quadrant. The ICC for the mean Standard RNFL thickness (and lower 95% confidence interval [CI]) in normal and glaucomatous eyes was 0.97 (0.96 CI) and 0.98 (0.97 CI), respectively. The ICC for the mean Fast RNFL thickness in normal and glaucomatous eyes was 0.95 (0.93 CI) and 0.97 (0.95 CI), respectively. Quadrant ICCs ranged between 0.79 and 0.97, with the nasal quadrant being the least reproducible of all four quadrants, using either the Standard or Fast RNFL program. The test-retest variability ranged from 3.5 microm for the average RNFL thickness measurements in normal eyes to 13.8 microm for the nasal quadrant measurements in glaucomatous eyes, which appeared to be the most variable. CONCLUSIONS: Reproducibility of RNFL measurements using the Stratus OCT is excellent in normal and glaucomatous eyes. The nasal quadrant appears to be the most variable measurement. Standard RNFL and Fast RNFL scans are equally reproducible and yield comparable measurements. These findings have implications for the diagnosis of glaucoma and glaucomatous progression.