Reproducibility of measuring retinal nerve fiber density. Comparison of optical coherence tomography with the nerve fiber analyzer and the Heidelberg retinal tomography device

Background. Glaucoma is associated with a progressive loss of retinal ganglion cell axons and the evaluation of the thickness of the retinal nerve fibre layer (RNFL) is important for early diagnosis and follow-up. Results of RNFL thickness measurements may vary according to the devices used. Therefore, the present study has analysed and compared the reproducibility of data obtained with three different instruments. Methods. RNFL thickness was determined using a circular identification line around the optic nerve head by optical coherence tomography (OCT), a Heidelberg Retina Tomograph (HRT) and a Nerve Fiber Analyser (NFA). Each eye was tested six times. The values for RNFL thickness were calculated for the superior, inferior, nasal and temporal areas. A one-way analysis of variance with random effects was chosen to estimate the variance components. The intraclass correlation coefficient (ICC) as a measure of reliabi-lity and the coefficient of variation (CV%) as a measure of precision were determined to estimate the reproducibility of RNFL thickness measurements. Results. With all three instruments, the reproducibility of measurements between the superior, inferior, temporal and nasal areas did not differ significantly suggesting that reproducibility does not depend on the thickness of the RNFL. Data obtained by NFA showed the highest ICC values (0.9) and lowest CV% values (7.0), followed by those obtained by HRT (reliability ICC 0.8; precision CV% 12). A markedly lower degree of reproducibility was found for the OCT compared to NFA and HRT (reliability ICC 0.5; precision CV% 15). Conclusion. The comparison of RNFL thickness measurements with OCT, NFA, and HRT showed that the NFA yielded the most reliable results followed by HRT.     

Discriminating ability of optical coherence tomography data in staging glaucomatous damage

Objective: To evaluate the ability of retinal nerve fibre layer (RNFL) thickness and optic nerve head (ONH) measurements, as determined by optical coherence tomography (OCT), to discriminate between normal eyesight and glaucoma and also among the different stages of glaucoma.Design: Observational cross-sectional study.Participants: Eighty-one controls and 213 glaucoma patients were enrolled in the study.Methods: The discriminating powers of OCT parameters for the detection of glaucoma and subgroups were compared by the area under the receiver operating characteristic (AUROC) curves.Results: The best RNFL thickness parameters for discriminating between early glaucoma and control eyes were inferior (0.74 [SE 0.04] μm), average (0.74 [SD 0.03] μm), and superior (0.68 [SD 0.03] μm). Among the ONH parameters, the best AUROC curve values were cup area (0.83 [SD 0.33]), cup/disc (C/D) area ratio (0.82 [SD 0.03]), and vertical integrated rim area (VIRA) (0.82 [SD 0.03]). The best AUROC values belonged to the RNFL thickness and were inferior (0.80 [SD 0.03]), superior (0.79 [SD 0.03]), and 6 o’clock (0.78 [SD 0.03]). The highest AUROC values were horizontal integrated rim width (HIRW) (0.74 [SD 0.04]), VIRA (0.64 [SD 0.04]), and rim area (0.63 [SD 0.04]) among the ONH parameters for early versus moderate glaucoma. The best AUROC values were inferior (0.81 [SD 0.03]), 6 o’clock (0.79 [SD 0.03]), and superior (0.78 [SD 0.04]) among the RNFL, and the best AUROC values were cup area (0.81 [SD 0.03]),VIRA (0.81 [SD 0.03]), and C/D area ratio (0.80 [SD 0.03]) among the ONH parameters, for moderate versus advanced glaucoma.Conclusions: RNFL and ONH OCT parameters might provide information for determining glaucomatous damage.     

Comparison of retinal nerve fibre layer measurements from time domain and spectral domain optical coherence tomography systems

Objective: To compare retinal nerve fibre layer (RNFL) thickness measurements acquired using spectral domain (SD) and time domain (TD) optical coherence tomography (OCT) systems.Study Design: Prospective clinical study.Participants: Twenty eyes of 20 healthy volunteers.Methods: All patients underwent 3 sets of circular OCT scans around the optic disc using both a TD OCT system, and a new SD OCT system. RNFL thickness measures within each of 4 quadrants, as well as overall mean RNFL thickness, were compared. Bland-Altman plots were also used to assess agreement.Results: Using the RTVue-100, RNFL measurements in the superior quadrant were, on average, 20 μm greater than those obtained from the Stratus (151.8 μm vs 131.7 μm, p < 0.0001). RNFL measures within other quadrants and overall mean RNFL thickness were not significantly different between systems. Bland-Altman plots indicated large differences between Stratus and RTVue-100 for all variables, with 95% limits of agreement spanning clinically important ranges of >50 μm for all RNFL variables.Conclusions: Significant differences exist between RNFL measurements obtained from the TD and SD OCT systems used in this study. These related, but distinct, technologies are not interchangeable. Further studies will be required to allow for appropriate clinical use of new SD OCT systems.     

OCT检测视网膜神经纤维层厚度及视盘参数在青光眼早期诊断应用

目的 通过光学相干断层成像术(OCT)检测视网膜神经纤维层(RNFL)厚度及视盘结构参数,结合视野改变,探讨OCT在青光眼早期诊断中的应用价值.方法 采用OCT对34只眼疑似闭角型青光眼(SG)患者、36只眼慢性闭角型青光眼(CACG)早中期患者、10只眼正常人行RNFL及视盘扫描,观察各组的RNFL厚度及视盘结构的图像特征;将各象限RNFL厚度和平均RNFL厚度的均数进行总体比较及任意两组间比较;将视乳头水平、垂直杯盘比及杯/盘面积比的均数进行比较;将平均RNFL厚度与视野指数进行相关分析.结果 三组间各象限RNFL厚度、平均RNFL厚度、视盘参数差异有统计学意义(P<0.05);正常人与SG组下方、上方及平均RNFL厚度差异有统计学意义(P<0.05);正常人与CACG早中期组各象限RNFL厚度及平均RNFL厚度差异均有统计学意义(P<0.05);CACG早中期组与SG组上方、下方、鼻侧及平均RNFL厚度差异有统计学意义(P相似文献   

不同分期青光眼结构与功能的相关性研究

目的 探讨不同分期的青光眼患者光学相干断层扫描(optical coherence tomography,OCT)检测的视网膜神经纤维层(retinal nerve fiber layer,RNFL)厚度与视野光敏感度的相关性.方法 用RTVue100-2频域OCT和OCTOPUSI01视野计对青光眼患者110例(110眼)进行检测.应用Spearman等级相关系数分析确定RNFL厚度与光敏感度的相关性,包括平均RNFL厚度与平均敏感度(mean sensitivity,MS)、上方和下方平均RNFL厚度与相对应半侧视野区MS的相关性.结果 早中晚期青光眼患者RNFL厚度分别为(99.30±9.43) μm、(82.30±9.06)μm、(69.50±7.54)μm,MS分别为(22.67±1.34)dB、(16.87±1.62)dB、(10.20±2.25)dB,各期青光眼组之间两两比较差异均有统计学意义(均为P＜0.05).早期青光眼患者平均RNFL厚度、上方和下方平均RNFL厚度与相对应视野区MS均呈正相关关系(平均RNFL厚度rs=0.412,上方平均RNFL厚度rs0.511,下方平均RNFL厚度rs=0.342,均为P＜0.05);中期青光眼患者平均RNFL厚度、上方平均RNFL厚度与相对应视野区MS呈正相关关系(平均RNFL厚度rs=0.372,上方平均RNFL厚度rs=0.407,均为p＜0.05),下方平均RNFL厚度与上方半侧视野区MS无相关性(rs=0.115,P＞0.05);晚期青光眼患者平均RNFL厚度、上方和下方平均RNFL厚度与相对应视野区MS均无相关性(平均RNFL厚度rs=0.057,上方平均RNFL厚度rs=0.050,下方平均RNFL厚度rs=0.226,均为P＞0.05).早期青光眼患者平均RNFL厚度与MS的相关性(rs=0.412,P=0.013)高于中期青光眼患者(rs=0.372,P=0.025),但二者的差异无统计学意义(P＞0.05).结论 随着青光眼病程的进展,青光眼结构和功能的相关性逐渐降低;晚期青光眼不存在显著结构和功能相关性.     

Early detection of thinning of retinal nerve fiber layer in glaucomatous eyes by optical coherence tomography 3000: analysis of retinal nerve fiber layer corresponding to the preserved hemivisual field

The retinal nerve fiber layer (RNFL) thickness was measured with the optical coherence tomography using version 3.0 software (OCT3000) in 153 eyes of 153 normal subjects. The mean of the average RNFL thickness over the entire 360 degrees in the control group was 92.5 +/- 12.9 microm which was significantly thinner than the normative data of 95.9 +/- 11.4 microm included with the OCT3000 (p < 0.01). The RNFL thickness decreased with increasing age (p < 0.01, r = -0.395). The RNFL thickness was also measured in 53 eyes of 53 patients with glaucoma whose superior (13 eyes) or inferior (40 eyes) perimetric hemifields were normal. Only the RNFL thickness corresponding to the preserved perimetric hemifields were measured by OCT3000 and scanning laser ophthalmoscopy (SLO). The RNFL thickness in the superior and inferior 30 degrees sectors, the maximum and average RNFL thickness in the superior (S(max) and S(avg)), and inferior quadrants (I(max) and I(avg)) were analyzed.The S(max), S(avg), I(max), I(avg), and the RNFL thickness in the superior (p < 0.05), superotemporal and inferotemporal sectors (p < 0.01) in the glaucoma patients without a nerve fiber layer defect (SLO) were significantly thinner than in the control subjects in same age. OCT3000 measurements showed that the RNFL thickness in glaucomatous eyes with normal perimetric visual fields and SLO was significantly thinner than the RNFL thickness in normal eyes.     

Scanning laser polarimetric analysis of retinal nerve fiber layer thickness in Turkish patients with glaucoma and ocular hypertension

PURPOSE: To assess the thickness of the retinal nerve fiber layer (RNFL) in patients with different stages of glaucoma, in comparison with ocular hypertensive (OHT) and healthy subjects in a Turkish population. METHODS: Scanning laser polarimetry was done with a GDx Nerve Fiber Analyzer (NFA, GDx version, 1.0.08) on 270 eyes with glaucoma, 52 OHT eyes, and 81 normal eyes. The eyes were classified as having early (146 eyes), moderate (66 eyes) and severe (58 eyes) glaucoma based on the Humphrey Visual Field indices. We compared 14 NFA parameters by analysis of variance (ANOVA) and Scheffe multiple comparison analysis. Receiver operator characteristic curves (ROC) and Fisher linear discriminant analysis (LDF) were used to measure the sensitivity and specificity of the NFA parameters. RESULTS: Except for symmetry, all NFA parameters showed significant differences between the groups (p<0.05). The eyes with glaucoma had significantly thinner RNFL than healthy eyes (p<0.01). The RNFL retardation measurements of OHT eyes were lower than controls, but higher than the early glaucoma group. The sensitivity and specificity of the GDx System were 87% and 72.8%, respectively. Applying LDF, the group with the highest sensitivity and specificity (85.9% and 74.1%) was determined as inferior ratio, superior/nasal ratio, superior maximum and the Number. CONCLUSIONS: Assessment of RNFL thickness with scanning laser polarimetry can distinguish glaucoma, OHT and normal subjects with relatively high sensitivity and specificity.     

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.     

Retinal nerve fibre layer thickness in full‐term children assessed with Heidelberg retinal tomography and optical coherence tomography: normal values and interocular asymmetry

Purpose: This study aimed to investigate normal values and interocular differences in retinal nerve fibre layer (RNFL) thickness, using optical coherence tomography (OCT) and Heidelberg retinal tomography (HRT), in 5–16‐year‐old children born at full‐term with normal birthweights. Methods: Fifty‐six children with normal visual acuity and refraction were examined with Stratus OCT and HRT. Three examinations were performed in each eye. One eye in each child was randomized for analyses of normal values. Findings in 54 eyes were evaluated. Mean values of RNFL thickness were calculated. Coefficients of variance and intraclass correlations were calculated. The correlation between right and left eyes and the limits of difference were determined for both methods. Results: Mean RNFL thickness was 98.4 μm (standard deviation [SD] 7.88 μm) assessed with OCT and 213.0 μm (SD 54.0 μm) assessed with HRT. No correlations between age or gender and RNFL thickness were found. The coefficients of variance were 2.9% and 5.6% for OCT and HRT, respectively, and intraclass correlations were 0.85 and 0.88, respectively. The limits of difference between the two eyes ranged from ?9 μm to 9 μm with OCT and from ?109 μm to 87 μm with HRT. Conclusions: Both OCT and HRT can be used in children aged 5–16 years, but OCT provides less variability in determinations of RNFL thickness, both in repeated examinations of the same eye and in comparisons between the two eyes. The present study provides values for normal RNFL thickness in healthy children which can be used to make comparisons with values in children with optic nerve diseases.     

Detecting the Progression of Normal Tension Glaucoma: A Comparison of Perimetry,Optic Coherence Tomography,and Heidelberg Retinal Tomography

Purpose

We compared the abilities of Stratus optical coherence tomography (OCT), Heidelberg retinal tomography (HRT) and standard automated perimetry (SAP) to detect the progression of normal tension glaucoma (NTG) in patients whose eyes displayed localized retinal nerve fiber layer (RNFL) defect enlargements.

Methods

One hundred four NTG patients were selected who met the selection criteria: a localized RNFL defect visible on red-free fundus photography, a minimum of five years of follow-up, and a minimum of five reliable SAP, Stratus OCT and HRT tests. Tests which detected progression at any visit during the 5-year follow-up were identified, and patients were further classified according to the state of the glaucoma using the mean deviation (MD) of SAP. For each test, the overall rates of change were calculated for parameters that differed significantly between patients with and without NTG progression.

Results

Forty-seven (45%) out of 104 eyes displayed progression that could be detected by red-free fundus photography. Progression was detected in 27 (57%) eyes using SAP, 19 (40%) eyes using OCT, and 17 (36%) eyes using HRT. In early NTG, SAP detected progression in 44% of eyes, and this increased to 70% in advanced NTG. In contrast, OCT and HRT detected progression in 50 and 7% of eyes during early NTG, but only 30 and 0% of eyes in advanced NTG, respectively. Among several parameters, the rates of change that differed significantly between patients with and without progression were the MD of SAP (p = 0.013), and the inferior RNFL thickness (p = 0.041) and average RNFL thickness (p = 0.032) determined by OCT.

Conclusions

SAP had a higher detection rate of NTG progression than other tests, especially in patients with advanced glaucoma, when we defined progression as the enlargement of a localized RNFL defect. The rates of change of the MD of SAP, inferior RNFL thickness, and average RNFL thickness differed between NTG patients with and without progression.     

视网膜神经纤维层定量测定在青光眼方面的应用

青光眼的主要病理过程是视网膜节细胞轴突（即视神经纤维）的丢失，故测量视网膜神经纤维层（ｒｅｔｉｎａｌｎｅｒｖｅｆｉｂｅｒｌａｙｅｒ，ＲＮＦＬ）来确定轴突丢失的程度在青光眼的早期诊断和治疗上具有非常重要的意义。近年来，计算机图像分析技术应用于眼科，它能对ＲＮＦＬ作出客观的量化检测。该文综述有关文献，就ＲＮＦＬ定量测定方法的原理，以及它们在青光眼ＲＮＦＬ损害检测方面的应用情况作一介绍。     

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.     

Nerve fibre layer changes in highly myopic eyes by optical coherence tomography

Objective: The purpose of this study was to investigate any correlations that may exist between retinal nerve fibre layer (RNFL) thickness and high myopia by optical coherence tomography (OCT).Design: Case-control study.Participants: Ten patients (20 eyes) with high myopia and 10 control patients (20 eyes) matched for age and sex were recruited from a database search of 1 vitreoretinal practice in Regina, Sask.Methods: The RNFL thickness of 10 highly myopic patients and 10 control patients matched for age and sex from a clinical practice was determined using the Stratus OCT. All 10 highly myopic patients selected for the study had a spherical equivalent of ≥−10.0 D OU and an intraocular pressure <21 mm Hg OU, and failed to display glaucomatous changes such as disc hemorrhages and glaucomatous cupping in either eye. None of the patients included in the study had evidence of concomitant ophthalmic disease and none had had previous refractive surgery. Axial length measurements were done on all patients using the IOL Master.Results: The mean (SD) RNFL thicknesses in the control and myopic groups were 108.8 (10.6) μm and 80.0 (18.6) μm, respectively, with t = 6.0 and p − 0.001. A negative correlation of −0.712 with p < 0.001 was found between RNFL thickness and axial length.Conclusions: When interpreting the RNFL thickness of highly myopic patients by OCT, careful attention must be given to the inherently thinner RNFL to avoid a false glaucoma diagnosis.     

早期青光眼不同类型视盘视网膜神经纤维层厚度分析

目的　探讨早期青光眼患者不同类型视盘的视网膜神经纤维层（ｒｅｔｉｎａｌｎｅｒｖｅｆｉｂｅｒｌａｙｅｒ,ＲＮＦＬ）厚度,以了解不同类型视盘的早期青光眼患者的ＲＮＦＬ厚度的特点。方法　应用光学相干断层扫描（ｏｐｔｉｃａｌｃｏｈｅｒｅｎｃｅｔｏｍｏｇｒａｐｈｙ,ＯＣＴ）技术检查视盘ＲＮ-ＦＬ厚度,将收集到的ＯＣＴ视盘检查结果分为６组:对照组大视盘组、中视盘组、小视盘组,每组各２０眼,早期青光眼大视盘组、中视盘组、小视盘组各２０眼。ＯＣＴ测量１２０眼各钟点平均ＲＮＦＬ厚度。检测对照组和早期青光眼患者１２个钟位的视盘ＲＮＦＬ厚度。结果　对照组不同类型视盘组的ＲＮＦＬ厚度曲线均在下方和上方形成双峰,在鼻侧和颞侧形成波谷,各组下方峰均高于上方峰。其中大视盘组患者ＲＮＦＬ厚度（１０５．６０±５．８７）μｍ,其次是中视盘组（１０７．０５±７．２９）μｍ和小视盘组（１０８．４０±７．２７）μｍ。对照组大、中、小视盘组的ＲＮＦＬ厚度差异无统计学意义（Ｐ＞０．０５）。早期青光眼ＲＮＦＬ厚度曲线的上或下方峰值降低,但仍然具备上、下方的双峰特征,各组的下方峰皆高于上方峰。其中大视盘组患者ＲＮＦＬ厚度最薄（７０．２５±１４．７１）μｍ,其次是中视盘组（８５. ５５±１５．３９）μｍ和小视盘组（８７．５５±９．４６）μｍ,大视盘组与中视盘组、小视盘组的视盘ＲＮＦＬ厚度的差异有统计学意义（均为Ｐ＜０．０５）,中视盘组与小视盘组的ＲＮＦＬ厚度差异无统计学意义（Ｐ＞０．０５）。早期青光眼患者与对照组不同类型视盘的ＲＮＦＬ均为厚度差异均有统计学意义（均为Ｐ＜０．０５）。结论　对照组不同大小的视盘并不影响ＲＮＦＬ厚度,早期青光眼患者视盘的ＲＮＦＬ厚度明显变薄,但仍然具备上、下方的双峰特征,各组的下方峰皆高于上方峰,其中大视盘患者的ＲＮＦＬ比中、小视盘受损更严重。     

Evaluation of relationship between retinal nerve fiber layer thickness progression and visual field progression in patients with glaucoma

Purpose

To evaluate the capability of optical coherence tomography (OCT), retinal nerve fiber layer (RNFL) thickness, and visual field (VF) measurements in glaucoma progression detection.

Methods

The study examined 62 eyes of 37 glaucoma patients observed over a 3-year period. All eyes underwent at least four serial RNFL measurements performed by Cirrus OCT, with the first and last measurements separated by at least 3 years. VF testing was performed by using the Swedish interactive threshold algorithm (SITA) Standard 30-2 program of the Humphrey field analyzer (HFA) on the same day as the RNFL imaging. Both serial RNFL thicknesses and VF progression were assessed by the guided progression analysis (GPA) software program. RNFL thickness progression was evaluated by event analysis. Total deviation (TD) in the superior or inferior hemifield was also examined.

Results

A total of 295 OCT scans and 295 VFs were analyzed. Five eyes exhibited progression by OCT only and 8 eyes exhibited progression by VF GPA only. When the analysis was based on the combined measurement findings, progression was noted in 6 eyes. The average of the progressive hemifield TD at baseline for combined RNFL and VF progression was ?3.21 ± 1.38 dB, while it was ?2.17 ± 1.14 dB for RNFL progression and ?9.12 ± 3.75 dB for VF progression. The average of the progressive hemifield TD indicated a significant advancement of VF progression as compared to RNFL progression (P = 0.002).

Conclusions

When a mild VF defect is present, OCT RNFL thickness measurements are important in helping discern glaucoma progression.     

Comparison of ability of time-domain and spectral-domain optical coherence tomography to detect diffuse retinal nerve fiber layer atrophy

Purpose

Our aim was to evaluate and compare diagnostic capabilities of time-domain (Stratus) and spectral-domain (Cirrus) optical coherence tomography (OCT) to detect diffuse retinal nerve fiber layer (RNFL) atrophy.

Methods

This study assessed 101 eyes from 101 glaucoma patients with diffuse RNFL atrophy and 101 eyes from 101 age-matched healthy individuals. Two experienced glaucoma specialists graded red-free RNFL photographs of eyes with diffuse RNFL atrophy using a four-level grading system. The area under the receiver operating characteristic curves (AUC) of normal eyes was compared with that of eyes with diffuse atrophy. Sensitivity and specificity of each OCT device were calculated on the basis of its internal normative database.

Results

The largest AUC for Stratus and Cirrus were obtained for average RNFL thicknesses (0.96 and 0.94, respectively). Comparison of the AUC with different RNFL atrophy grades revealed no significant difference between the two OCT devices. Using an internal normative database at a <5 % level, the overall sensitivity of Stratus ranged from 58.0 to 84.0 %, whereas that of Cirrus ranged from 75.0 to 87.0 %. According to the normative database, the highest Stratus sensitivity was obtained with the temporal–superior–nasal–inferior–temporal (TSNIT) thickness graph, and the highest Cirrus sensitivity with the TSNIT thickness graph and the deviation map.

Conclusions

The AUC obtained from Cirrus were comparable with those from Stratus. On the basis of their normative databases, these devices had similar diagnostic accuracy. Our results suggest that the diagnostic capabilities of the two instruments to detect diffuse RNFL atrophy are similar.     

A comparison of optical coherence tomography and retinal nerve fiber layer photography for detection of nerve fiber layer damage in glaucoma

PURPOSE: To compare optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness measurements with established methods for assessment of glaucomatous damage using RNFL photography and visual field testing. DESIGN: Cross-sectional study. PARTICIPANTS: Fifty-eight eyes of 58 healthy volunteer ocular hypertensive patients, glaucoma suspect patients, and glaucoma patients were included. METHODS: Optical coherence tomography 3.4-mm diameter circular scans were obtained within 3 months of RNFL photography and standard achromatic visual field testing. Three independent observers graded RNFL photographs using two standardized protocols. For each method, superior and inferior arcuate bundles were scored separately, and interobserver and intraobserver variation was measured. Standard achromatic visual field mean deviation in the superior and inferior hemifields was compared with RNFL damage as assessed by photography and OCT RNFL thickness measurements. MAIN OUTCOME MEASURES: Visual field mean deviation and severity of glaucomatous RNFL damage as assessed by photography. RESULTS: Optical coherence tomography RNFL thickness decreased with increasing RNFL damage as assessed by photography using both methods of photographic assessment. Standard achromatic perimetry mean deviation was significantly associated with OCT RNFL thickness (R(2) = 35%-43%) and RNFL photography severity score (R(2) = 18%-29%). CONCLUSIONS: These results suggest that the OCT shows promise for providing quantitative measures of RNFL thickness for diagnosing and monitoring glaucoma.     

Increasing scans per examination improves the reproducibility on retinal nerve fiber layer measurements by optical coherence tomography.

PURPOSE: To investigate whether increasing the number of scans per examination would improve the reproducibility of retinal nerve fiber layer (RNFL) measurements by optical coherence tomography (OCT) in healthy and glaucomatous eyes. METHODS: A total of 28 eyes of 28 healthy subjects and 20 eyes of 20 patients with primary chronic open-angle glaucoma were recruited. OCT RNFL assessments were obtained in one randomly selected eye. Each subject underwent seven scans on five separate occasions within a 1-month period. RESULTS: In the healthy group, the intervisit mean coefficient of variations (COV's) for the average RNFL thickness (100 sampling points) and the quadrant RNFL measurements (25 sampling points) were similar in a series of three, five, and seven scans per examination (p > 0.05), but COV's for the two clock-hour segment measurements (seven sampling points, superotemporal and inferotemporal) were significantly lower in a series of five and seven scans per examination than that of three scans per examinations (p < 0.01). In the glaucoma groups, COV's for the two quadrant (superior and inferior) and five clock-hour segment RNFL measurements (superior, superotemporal, temporal, inferotemporal, and superonasal) were significantly lower in a series of five and seven scans per examination than that of three scans per examination (p < 0.01). There was no statistical difference in the COV's between a series of five scans and that of seven scans per examination in all OCT RNFL thickness parameters in healthy and glaucomatous eyes (p > 0.05). Similar results were observed with intravisit COV comparisons. CONCLUSION: Increasing the number of scans per examination may improve the reproducibility of quadrant and clock-hour segment OCT RNFL measurements in healthy and glaucomatous eyes. A series of five scans per examination is recommended for OCT RNFL measurements.     

Using retinal architecture to help characterize multiple sclerosis patients

Objective: We compared retinal nerve fibre layer (RNFL) thickness and visual function in a heterogeneous multiple sclerosis (MS) cohort to determine whether optical coherence tomography (OCT) may complement the existing methods used to characterize MS patients.Design: Cross-sectional cohort study.Participants: One hundred and ninety-three patients with optic neuritis (ON) as a clinically isolated syndrome (CIS) (n = 63), relapsing-remitting MS (RRMS) (n = 108), secondary progressive MS (SPMS) (n = 13), and primary progressive MS (PPMS) (n = 9).Methods: All patients underwent standardized ophthalmic, neurological, and OCT testing at a single academic institution.Results: RNFL values were reduced in PPMS (94.3 μm), RRMS (99.6 μm), and SPMS eyes (84.7 μm) relative to CIS eyes (105.7 μm) (p < 0.0001). RNFL values were lower in eyes with recurrent ON (64.2 μm) relative to eyes affected by a single ON event (86.3 μm) (p < 0.0001). The strongest correlation between RNFL thickness and neurological disability occurred in RRMS patients (r = −0.51, p < 0.0001). RNFL thickness correlated with visual field sensitivity for CIS (r = 0.23, p < 0.01) and RRMS (r = 0.22, p < 0.01) patients. Simple linear regression showed that every 10 μm decrease in RNFL correlated with a 5.8 decibel decrease in visual field sensitivity (adjusted R² = 0.35, p < 0.0001) for RNFL values less than 75 μm.Conclusions: There were robust correlations between RNFL thickness and visual function, particularly in ON eyes. OCT may complement the existing tools used to characterize MS patients, but further studies are needed.     

青光眼视网膜神经纤维层厚度变化及其与视野缺损的相关性

目的　利用光学相干断层扫描（ｏｐｔｉｃａｌｃｏｈｅｒｅｎｃｅｔｏｍｏｇｒａｐｈｙ,ＯＣＴ）检测早期原发性开角型青光眼和可疑青光眼患者视网膜神经纤维层（ｒｅｔｉｎａｌｎｅｒｖｅｆｉｂｅｒｌａｙｅｒ,ＲＮＦＬ）厚度的变化,并分析其与视野缺损的相关性。方法　收集来我院就诊的可疑青光眼患者３５例（６３眼）为Ａ组,早期原发性开角型青光眼患者４１例（７２眼）为Ｂ组,对照组３４例（６６眼）为Ｃ组,采用ＯＣＴ仪和Ｈｕｍｐｈｒｅｙ７４０ｉ全自动视野计分别对３组受检者进行视盘周围ＲＮ-ＦＬ厚度和视野检测,比较３组患者的ＲＮＦＬ厚度,分析青光眼组ＲＮＦＬ厚度与视野缺损间的关系。结果　Ａ组的上方、下方象限及平均ＲＮＦＬ厚度与Ｃ组对应象限比较,差异均有统计学意义（均为Ｐ＜０．０５）;Ｂ组与Ｃ组比较平均及各象限ＲＮＦＬ厚度差异均有统计学意义（均为Ｐ＜０．０５）;Ａ组与Ｂ组比较上方、下方、鼻侧象限及平均ＲＮＦＬ厚度差异均有统计学意义（均为Ｐ＜０．０５）。三组受检者各象限及全周视野缺损两两比较,差异均有统计学意义（均为Ｐ＜０．０５）。Ｂ组平均及各象限ＲＮＦＬ厚度与视野缺损程度均呈负相关（均为Ｐ＜０．０５）。结论　青光眼患者ＲＮＦＬ厚度变薄,并且与视野缺损程度呈负相关。