Comparability of retinal nerve fiber layer thickness measurements of optical coherence tomography instruments

PURPOSE: To compare retinal nerve fiber layer (RNFL) measurements between two ocular coherence tomography (OCT) instruments (OCT 2000 and Stratus OCT; Carl Zeiss Meditec, Dublin, CA) and compare their diagnostic precision. METHODS: One hundred thirty-nine consecutive subjects were imaged (3 x 3.4-mm diameter circular scans) on the same day with each instrument. Thirty-five patients were excluded due to poor-quality images. RNFL thicknesses measured by the two instruments were compared, and receiver operating characteristic (ROC) curves were used to determine diagnostic precision. RESULTS: A randomly selected eye of each of 104 participants (28 with open-angle glaucoma, 40 with suspected glaucoma, and 36 healthy subjects) was analyzed. RNFL thickness measurements generally were thicker with OCT 2000 than with Stratus OCT. The difference in global RNFL thickness between instruments was within 20 microm in 66 (65%) of subjects and within 10 microm (the instrument's limit of resolution) in 25 (25%) subjects. Application of a correction factor to OCT 2000 measurements predicted Stratus OCT RNFL thickness within 10 microm of the observed measurement in 75% of the eyes. For both instruments, highest ROC curve areas (better discrimination between glaucomatous and normal eyes) were found in the inferior sector. Discrimination using global RNFL thickness was better with Stratus OCT than OCT 2000 (P = 0.043). CONCLUSIONS: RNFL thickness measurements measured by OCT 2000 can be approximated to measurements made by Stratus OCT using correction factors calculated by this study. However, there remains considerable variability that exceeds the limits of resolution afforded by the instruments themselves. Therefore comparisons between instruments using these approximations should be interpreted with caution.     

Comparison of retinal nerve fiber layer thickness between Stratus and Spectralis OCT

Purpose

To compare the peripapillary retinal nerve fiber layer (RNFL) thickness of normal patients and those with various glaucoma diseases by time domain (Stratus) and spectral domain (Spectralis) optical coherence tomography (OCT).

Methods

The RNFL thickness as measured by the Stratus and Spectral OCT was compared (paired t-test). The relationship and agreement of RNFL thickness between the two OCT modalities were evaluated by Pearson correlation, Bland-Altman plot, and area under the receiver operating characteristic curve.

Results

Two-hundred seventeen eyes of 217 patients, including twenty-four normal eyes, ninety-one glaucoma suspects, seventy-six normal tension glaucoma cases, and twenty-six primary open angle glaucoma cases (POAG) were analyzed. The peripapillary RNFL thicknesses as measured by Stratus OCT were significantly greater than those measured by Spectralis OCT. However, in quadrant comparisons, the temporal RNFL thickness obtained using Stratus OCT were significantly less than those obtained using Spectralis OCT. Correlations between RNFL parameters were strong (Pearson correlation coefficient for mean RNFL thickness = 0.88); a high degree of correlation was found in the POAG group. Bland-Altman plotting demonstrated that agreement in the temporal quadrant was greater than any other quadrant.

Conclusions

Both OCT systems were highly correlated and demonstrated strong agreement. However, absolute measurements of peripapillary RNFL thickness differed between Stratus OCT and Spectralis OCT. Thus, measurements with these instruments should not be considered interchangeable. The temporal quadrant was the only sector where RNFL thickness as measured by Spectralis OCT was greater than by Stratus OCT; this demonstrated greater agreement than other sectors.     

Comparison of the GDx VCC scanning laser polarimeter and the stratus optical coherence tomograph in the detection of band atrophy of the optic nerve

AIM: To compare the ability of scanning laser polarimeter (SLP) with variable corneal compensation (GDx VCC) and optical coherence tomograph (Stratus OCT) to discriminate between eyes with band atrophy (BA) of the optic nerve and healthy eyes. METHODS: The study included 37 eyes with BA and temporal visual field (VF) defects from chiasmal compression, and 29 normal eyes. Subjects underwent standard automated perimetry (SAP) and retinal nerve fibre layer (RNFL) scans using GDx VCC and Stratus OCT. The severity of the VF defects was evaluated by the temporal mean defect (TMD), calculated as the average of 22 values of the temporal total deviation plot on SAP. Receiver operating characteristic (ROC) curves were calculated. Pearson's correlation coefficients were used to evaluate the relationship between RNFL thickness parameters and the TMD. RESULTS: No significant difference was found between the ROC curves areas (AUCs) for the GDx VCC and Stratus OCT with regard to average RNFL thickness (0.98 and 0.99, respectively) and the superior (0.94; 0.95), inferior (0.96; 0.97), and nasal (0.92; 0.96) quadrants. However, the AUC in the temporal quadrant (0.77) was significantly smaller (P<0.001) with GDx VCC than with Stratus OCT (0.98). Lower TMD values were associated with smaller RNFL thickness in most parameters from both equipments. CONCLUSION: Adding VCC resulted in improved performance in SLP when evaluating eyes with BA, and both technologies are sensitive in detecting average, superior, inferior, and nasal quadrant RNFL loss. However, GDx VCC still poorly discriminates RNFL loss in the temporal quadrant when compared with Stratus OCT.     

Glaucoma detection using different Stratus optical coherence tomography protocols

PURPOSE: To examine and compare the diagnostic accuracy of retinal nerve fibre layer (RNFL) thickness measurements using different Stratus optical coherence tomography (OCT) scanning protocols. METHODS: Stratus OCT data for 90 healthy subjects and 62 glaucoma patients with mild or moderate visual field loss were prospectively collected and analysed using four RNFL thickness protocols that differed in terms of image resolution and number of scans. Cut-off levels corrected for age and refractive error were defined by reference values derived from an independent normal database. Sensitivity and specificity were calculated for average RNFL thickness for the full circle scan, and for the quadrant and clock hour circle scan sectors at p < 5% and p < 1% cut-off values. RESULTS: Regular- and high-resolution images performed equally well, and single best-quality scans were as good as the average of three scans to distinguish between healthy and glaucomatous eyes. Full circle RNFL thickness yielded similar or better diagnostic accuracy than that of sectors. Sensitivities ranged from 84% to 87% and specificities from 89% to 93% for full circle RNFL thickness at the p < 5% cut-off level. CONCLUSIONS: The abilities of four different Stratus OCT RNFL thickness protocols to distinguish between eyes with predominantly mild glaucomatous field loss and healthy eyes were very similar. Thus diagnostic accuracy did not differ between high- and regular-resolution protocols, nor between global (full circle) and localized (sector) OCT parameters, which suggests a diffuse component in early glaucomatous RNFL damage.     

Comparison of the influence of cataract and pupil size on retinal nerve fibre layer thickness measurements with time-domain and spectral-domain optical coherence tomography

Background: To investigate and compare the effect of cataract and pupil size on retinal nerve fibre layer (RNFL) thickness measurements using spectral‐domain optical coherence tomography (Cirrus OCT) and time‐domain OCT (Stratus OCT). Design: Prospective, hospital‐based study. Participants: Twenty‐five eyes from 25 normal subjects undergoing cataract surgery. Methods: Three retinal nerve fibre layer (RNFL) thickness measurements were taken before and after dilation, preoperatively and postoperatively, using Cirrus 200 × 200 Optic Disc Scan and Stratus Fast RNFL Scan. Main Outcome Measures: Linear regression, intraclass correlation coefficient (ICC) and coefficient of variation analysis. Results: Cataract removal caused significant increase in RNFL measurements in both modalities (Cirrus P < 0.02; Stratus P < 0.001). There was no significant difference in the increase in measurements between the two machines. Pupil dilation had variable and non‐statistically significant effect in both (P > 0.05). ICC showed excellent reproducibility with Cirrus OCT after mydriasis, preoperatively (ICC = 0.78–0.90) and postoperatively (ICC = 0.90–0.97), but poor reproducibility before mydriasis (P < 0.75). Stratus OCT achieved excellent reproducibility after cataract removal both before (ICC = 0.86–0.96) and after mydriasis (ICC = 0.92–0.95), but poor reproducibility before cataract surgery (P < 0.75). Conclusions: Cataracts, not pupil size, cause significant underestimation of RNFL measurements in both Cirrus and Stratus OCT. The extent of influence exerted does not appear different between the two instruments. Reproducibility of each machine appears to be affected differently. Mydriasis is required to achieve excellent reproducibility with Cirrus OCT, and media clarity is required with Stratus OCT.     

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.     

光学相干断层成像术对原发性开角型青光眼视网膜神经纤维层的定性和定量检测

OBJECTIVE: To study the characteristics of optical coherence tomography (OCT) of primary open angle glaucoma (POAG), the difference of retinal nerve fiber layer (RNFL) thickness between normal persons and patients with POAG and the correlation between RNLF and visual field index. METHODS: Eighty-three cases (149 eyes) with POAG and 83 normal persons (150 eyes) were tested by OCT with circular scans around the optic nerve head (diameter = 3.46 mm) to observe the features of OCT. Statistic analysis was taken to compare the difference of RNFL thickness in quadrants and means between normal and glaucomatous group, and the difference of the thickness among the stages in POAG. Linear correlation and regression analysis was used to show the correlation between RNFL thickness and visual field index of 115 eyes of glaucomatous patients. RESULTS: The RNFL thickness measured by OCT in normal subjects is the thickest in superior and inferior quadrants, less in thickness in temporal and the thinnest in nasal quadrant. The curve showed double peaks. The RNFL of glaucomatous patients showed local thinness or defect, diffuse thinness or combination of the above two types. The mean RNFL thickness of normal group was (90.1 +/- 10.8) microm, (140.4 +/- 10.5) microm, (85.2 +/- 14.0) microm, (140.4 +/- 9.7) microm and (114.2 +/- 6.0) microm, of glaucomatous group was (56.0 +/- 31.0) microm, (81.0 +/- 36.3) microm, (47.1 +/- 27.5) microm, (73.4 +/- 38.4) microm and (64.6 +/- 28.8) microm in temporal, superior, nasal, inferior quadrant and the whole area, respectively. There is significant difference of RNFL thickness between the normal and glaucomatous group (P < 0.000), and there are significant differences among the three stages (early, developing and late) of glaucomatous group (P < 0.000). There is a close negative relationship between RNFL thickness and visual field index (r = -0.796, P < 0.0001). The sensitivity and specificity of RNFL thickness measured by OCT were 93.3% and 92.0%, respectively. CONCLUSION: OCT can quantitatively measure the RNFL thickness and show the difference of RNFL between normal persons and glaucomatous patients. The RNFL thickness gradually decreases while visual field defect increases with the development of POAG.     

Reproducibility of retinal nerve fiber layer measurements across the glaucoma spectrum using optical coherence tomography

Purpose:

The purpose was to determine intra-session and inter-session reproducibility of retinal nerve fiber layer (RNFL) thickness measurements with the spectral-domain Cirrus optical coherence tomography (OCT)^® (SD-OCT) in normal and glaucomatous eyes, including a subset of advanced glaucoma.

Materials and Methods:

RNFL measurements of 40 eyes of 40 normal subjects and 40 eyes of 40 glaucomatous patients including 14 with advanced glaucoma were obtained on the Cirrus OCT^® (Carl Zeiss Meditec, Dublin, CA, USA) five times on 1-day (intra-session) and on five separate days (inter-session). Intraclass correlation coefficient (ICC), coefficient of variation (COV), and test-retest variability (TRT) values were calculated for mean and quadrant RNFL in each group separately. Reproducibility values were correlated with age and stage of glaucoma.

Results:

For intra-session reproducibility, the ICC, COV, and TRT values for mean RNFL thickness in normal eyes were 0.993, 1.96%, and 4.02 µm, respectively, 0.996, 2.39%, and 3.84 µm in glaucomatous eyes, and 0.996, 2.41%, and 3.70 µm in advanced glaucoma. The corresponding inter-session values in normal eyes were 0.992, 2.16%, and 4.09 µm, 0.995, 2.62%, and 3.98 µm in glaucoma and 0.990, 2.70%, and 4.16 µm in advanced glaucoma. The mean RNFL thickness measurements were the most reproducible while the temporal quadrant had the lowest reproducibility values in all groups. There was no correlation between reproducibility and age or mean deviation on visual fields.

Conclusions:

Peripapillary RNFL thickness measurements using Cirrus OCT^® demonstrated excellent reproducibility in normal and glaucomatous eyes, including eyes with advanced glaucoma. Mean RNFL thickness measurements appear to be the most reproducible and probably represent the best parameter to use for longitudinal follow-up.     

Improved reproducibility of retinal nerve fiber layer thickness measurements with the repeat-scan protocol using the Stratus OCT in normal and glaucomatous eyes

Background  Optical coherence tomography has become within the last years an established imaging technique with many applications in ophthalmology, and an important tool which contributes to earlier and more accurate diagnosis of glaucoma. As a consequence, detection sensitivity is highly valued. The aim of this study was to assess the reproducibility of peripapillary retinal nerve fiber layer (RNFL) thickness measurements by the Stratus Optical Coherence Tomograph (OCT) using the Fast- and Repeat-scan protocols in normal and glaucomatous eyes. Methods  In the clinical setting, RNFL thickness measurements were obtained from a control group of 40 subjects, consisting of 20 normal volunteers and 20 glaucoma patients. One eye was randomly chosen from each subject, and underwent five RNFL thickness measurements with the Fast- and five with the Repeat-scan protocol, which was also based on the Fast-scan mode. Reproducibility was assessed by the intraclass correlation coefficient (ICC) and the coefficient of variation (CV) for the overall mean RNFL thickness and for each quadrant and clock hour of the peripapillary area. Results  The Repeat-scan protocol yielded higher ICC and lower CV values in all quadrants and clock hours of the peripapillary area, both in normal and glaucomatous subjects. The difference in CV values between Fast- and Repeat-scan protocol measurements reached statistical significance in the temporal quadrant (P = 0.021) and in clock hour sectors 8, 9 and 12 (P = 0.022, 0.017 and 0.03 respectively). ICC (and CV) for the temporal-, superior-, nasal- and inferior-quadrant RNFL thickness was: for the Fast-scan protocol, 0.913 (7.4%), 0.925 (6.97%), 0.828 (10.31%), 0.964 (4.89%) respectively; and for the Repeat-scan protocol, 0.965 (5.08%), 0.958 (5.26%), 0.906 (8.12%) 0.968 (4.6%) respectively. Conclusions  Reproducibility of RNFL thickness measurements with the Fast- and Repeat-scan protocols by the Stratus OCT is proved to be very high both in normal and glaucomatous subjects. The Repeat-scan protocol shows higher ICC and lower CV values, statistically significant especially on the temporal side of the peripapillary area, which may indicate a higher reproducibility and greater agreement of measurements. These findings support the fact that the Repeat-scan protocol might be considered as a more precise method for evaluation of RNFL thickness. No financial interests in any of the products mentioned in the study.     

Correlation between retinal nerve fibre layer thickness and optic nerve head size: an optical coherence tomography study

AIM: To investigate the correlation between retinal nerve fibre layer (RNFL) thickness and optic nerve head (ONH) size in normal white subjects by means of optical coherence tomography (OCT). METHODS: 54 eyes of 54 healthy subjects aged between 15 and 54 underwent peripapillary RNFL thickness measurement by a series of three circular scans with a 3.4 mm diameter (Stratus OCT, RNFL Thickness 3.4 acquisition protocol). ONH analysis was performed by means of six radial scans centred on the optic disc (Stratus OCT, Fast Optic Disc acquisition protocol). The mean RNFL values were correlated with the data obtained by ONH analysis. RESULTS: The superior, nasal, and inferior quadrant RNFL thickness showed a significant correlation with the optic disc area (R = 0.3822, p = 0.0043), (R = 0.3024, p = 0.026), (R = 0.4048, p = 0.0024) and the horizontal disc diameter (R = 0.2971, p = 0.0291), (R = 0.2752, p = 0.044), (R = 0.3970, p = 0.003). The superior and inferior quadrant RNFL thickness was also positively correlated with the vertical disc diameter (R = 0.3774, p = 0.0049), (R = 0.2793, p = 0.0408). A significant correlation was observed between the 360 degrees average RNFL thickness and the optic disc area and the vertical and horizontal disc diameters of the ONH (R = 0.4985, p = 0.0001), (R = 0.4454, p = 0.0007), (R = 0.4301, p = 0.0012). CONCLUSIONS: RNFL thickness measurements obtained by Stratus OCT increased significantly with an increase in optic disc size. It is not clear if eyes with large ONHs show a thicker RNFL as a result of an increased amount of nerve fibres or to the shorter distance between the circular scan and the optic disc edge.     

Glaucomatous retinal nerve fibre layer defects may be identified in Stratus OCT images classified as normal

Purpose: We aimed to compare the retinal nerve fibre layer (RNFL) in different Stratus optical coherence tomography (OCT) images in glaucoma eyes with RNFL thickness values within normal limits. Methods: We studied the Stratus OCT high‐resolution standard protocol for assessment of peripapillary RNFL thickness. The four glaucoma eyes presented (with reproducible visual field defects, mean deviations from ? 3.49 dB to ? 0.49 dB and structural loss on RNFL and/or disc photography) had results within the 95% normal limits for all OCT parameters (full circle, quadrant or clock hour mean RNFL thickness). We qualitatively compared the RNFL in pseudo‐colour and grey‐scale images defined by the Stratus OCT software with what appeared to be the RNFL when not defined automatically (and in raw data OCT images). Results: A localized RNFL defect was identified in conventional 495‐nm RNFL photographs in all four patients. Obviously, in these selected eyes, the atrophy was not picked up by the OCT RNFL border algorithm, and at the corresponding location a localized RNFL atrophy (narrowing of the high signal intensity RNFL) was either not or just barely detectable in pseudo‐colour OCT. However, defects seemed to be present in OCT grey‐scale and raw data images in all four eyes. Conclusions: Our observations suggest that OCT images obtained in glaucoma eyes that are misclassified by the standard statistical analyses of Stratus OCT may contain information indicating RNFL defects. Thus, the current diagnostic ability of OCT in glaucoma can probably be extended.     

A comparison of structural measurements using 2 Stratus optical coherence tomography instruments

PURPOSE: To compare measures of peripapillary retinal nerve fiber layer (RNFL) thickness, optic disc topography, and central foveal thickness generated using 2 different Stratus optical coherence tomography (OCT) instruments. METHODS: Ten normal subjects and 10 glaucoma subjects were included. One randomly selected eye per subject was scanned consecutively using a fast RNFL thickness protocol, fast macular thickness map, and fast optic disc protocol by 2 experienced operators on 2 instruments. The order of the machines and operators were randomized. The output power of each machine was measured using an optical power meter. For each OCT measurement 2 factor fixed effects analyses of variance were performed and a restricted maximum likelihood variance component analysis of the proportion of variance due to subject, operator, and machine was calculated. RESULTS: Significant differences (P相似文献   

The effect of axial length on the variability of Stratus optical coherence tomography

Purpose

To evaluate the effect of axial length on the variability of retinal nerve fiber layer (RNFL) thickness measurements using the Stratus optical coherence tomography (OCT) in normal and glaucomatous eyes.

Methods

We measured the RNFL thickness in 474 subjects using the Stratus OCT twice during the same day. Axial length was measured with the IOLMaster, and refractive error was the absolute value of the spherical equivalent measured with an auto ref-keratometer. Standard deviation in overall mean RNFL thickness was used as the dependent variable to identify significant correlations.

Results

Long axial length affected the variability in the RNFL thickness value by stratus OCT at the temporal quadrant (p = 0.006) and clock-hour sector 9 (p = 0.001). Refractive error also affected the variability of the RNFL thickness value by stratus OCT at the temporal quadrant (p = 0.025) and clock-hour sector 9 (p = 0.024).

Conclusions

It is clinically significant that longer axial length demonstrates greater variability in temporal area as detected by OCT, a measurement which correlates with the preferably damaged position in the myopic glaucoma eye.     

Comparison of the Diagnostic Ability of Retinal Nerve Fiber Layer Thickness Measured using Time Domain and Spectral Domain Optical Coherence Tomography in Primary Open Angle Glaucoma

 Purpose: To evaluate and compare the diagnostic ability of retinal nerve fiber layer (RNFL) thickness measurements using time domain (Stratus) and spectral domain (Cirrus HD) optical coherence tomography (OCT) in preperimetric and early primary open angle glaucoma (POAG). Methods: A total 62 eyes of 62 normal subjects, 47 eyes of 47 early perimetric damage POAG patients and 30 eyes of 30 preperimetric glaucoma patients were chosen in the study. All the subjects underwent peripapillary RNFL thickness measurements using Stratus OCT and Cirrus HD-OCT on the same day by a single trained operator. The RNFL thickness measured by Stratus OCT and Cirrus HD-OCT was statistically compared using paired t-tests. The relationship between RNFL thickness measured by two OCT instruments was evaluated using Pearson’s correlation coefficient. Areas under the receiver operating characteristic curves (AROC) were calculated and compared. Results: RNFL thickness measured using Stratus OCT was generally thicker than that using Cirrus HD-OCT(P＜0.05). A highly significant correlation between the two OCT instruments measurements was found in four quadrants and average RNFL thickness measurements (P＜0.001). The average RNFL thickness of Cirrus HD-OCT had significantly (P = 0.006) higher diagnostic ability (AROC = 0.951) than that of Stratus OCT (AROC = 0.881) in preperimetric glaucoma. There were no significant differences between the AROCs for other RNFL thickness parameters from Cirrus HD-OCT and Stratus OCT in preperimetric and early glaucoma (P＞0.05). Conclusion: Significant differences and an excellent correlation were noted in terms of RNFL thickness measurements using Stratus OCT and Cirrus HD-OCT. Cirrus HD-OCT presented higher diagnostic ability for preperimetric glaucoma.     

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.     

Stratus OCT与GDxVCC测量正常人与青光眼患者视网膜神经纤维层厚度比较研究

目的 比较相干光断层扫描仪StratusOCT与激光偏振光视网膜扫描仪GDxVCC测量视网膜神经纤维层(RNFL)厚度的相关性及差异,探讨两者测量值与视野的相关性及其对青光眼的诊断效能.方法 84例原发性开角型青光眼(POAG)患者及50名正常人,随机选取一眼进行StratusOCT和GDxVCCRNFL厚度测量及Humphery自动视野计检查.相关分析比较两种仪器测量的全周、上方、下方RNFL厚度;回归分析研究视野的平均偏差与两种仪器测量的RNFL厚度值之间的关系;ROC曲线下面积分析两种仪器诊断青光眼的效能.结果 Stratus OCT测量正常人及POAG患者的全周RNFL厚度分别为(100.00±7.36)μm和(75.12±17.11)μm,GDxVCC对应测量值(57.16±5.05)μm和(48.00.4±8.46)μm.两种仪器测量的RNFL厚度呈线性相关(r>0.75).两种仪器测量的RNFL厚度值与视野的平均偏差呈正相关,三次曲线拟合度较直线相关的拟合度好.对于青光眼诊断,Stratus OCT的最大ROC曲线下面积为0.908,GDxVCC最大ROC曲线下面积为0.842.结论 Stratus OCT与GDxVCC测量RNFL厚度值存在差异,但两者呈线性相关,均与视野的平均偏差呈曲线相关.两种仪器诊断青光眼的效能均较好.     

Glaucoma detection by Stratus OCT

PURPOSE: To investigate the diagnostic accuracy of retinal nerve fiber layer thickness (RNFLT) summary report parameters from Stratus optical coherence tomography (OCT) in glaucoma patients. PATIENTS AND METHODS: We obtained Stratus OCT measurements of peripapillary circle scans (average values) of the regular image resolution "FAST RNFLT" protocol, and of 1 circle scan of the high resolution "RNFLT" protocol in one eye of each of 62 glaucoma patients with mild or moderate visual field (VF) loss and 90 healthy subjects. Sensitivity, specificity, and diagnostic accuracy [(true positive+true negative)/all] were evaluated for all summary report parameters including the newer (eg, "Imax," the maximum thickness point in the inferior quadrant) at the normative limits of the Stratus OCT. RESULTS: The diagnostic accuracy of full circle RNFLT using the 5% normal limit was 89% with the FAST RNFLT and 87% with the RNFLT protocol; this was at least as good as any other parameter. The diagnostic performance of the 2 protocols did not differ significantly for most parameters. In eyes with mild VF loss (n=39) diagnostic sensitivities reached 72% and 77% at specificities >or=95% using the FAST RNFLT and RNFLT protocol, respectively. CONCLUSIONS: The diagnostic accuracy of the full circle RNFLT was as good as any Stratus OCT parameter on the basis of the peripapillary RNFL thickness measurements, including localized measurements. The sensitivity was moderately high in patients with mild glaucomatous VF loss. There seems to be room for further development of OCT interpretation tools for early diagnosis of glaucoma.     

Optical coherence tomography as a tool for monitoring pediatric pseudotumor cerebri

PURPOSE: To evaluate optical coherence tomography (OCT) measurement of peripapillary retinal nerve fiber layer (RNFL) and macular thickness in children with pseudotumor cerebri. METHODS: Prospective observational series of children with pseudotumor cerebri compared against controls matched for age and gender. We included 11 pediatric subjects with clinical pseudotumor cerebri and 37 normal controls. Subjects underwent a complete eye examination including stereo disk photographs and OCT. Peripapillary RNFL and macular thickness were evaluated using the Stratus OCT 3000. The peripapillary RNFL was evaluated with two protocols: Fast RNFL Map protocol with values divided in eight sections, made up of four quadrants, each with an inner and outer ring, and Fast RNFL Thickness (3.4) protocol, using values presented for four quadrants. A Fast Macular Thickness Map was also obtained, and results reported similarly included eight sections, made up of four quadrants, each with an inner and outer ring. RESULTS: The Fast RNFL Map protocol showed an increased RNFL thickness (pseudotumor cerebri vs controls) in the temporal and superior quadrants. The Fast RNFL Thickness (3.4) protocol showed a thicker average RNFL for pseudotumor cerebri eyes compared with controls (125.7 vs 106.5 microm, p < 0.0001). The Fast Macular Thickness Map showed an increased RNFL thickness in the nasal quadrant for the inner ring. The macular volumes for pseudotumor cerebri versus control eyes were 7.21 versus 6.97 mm(3), respectively (p = 0.005). CONCLUSIONS: OCT shows increased RNFL and macular thickness in pseudotumor cerebri and may be a useful clinical tool in these children.     

The effect of various factors on variability of retinal nerve fiber layer thickness measurements using optical coherence tomography

Purpose

To evaluate the effects of various factors on the variability of retinal nerve fiber layer (RNFL) thickness measurements using the Stratus optical coherence tomography (OCT) in normal and glaucomatous eyes.

Methods

Four hundred seventy-four subjects (103 normal eyes and 371 glaucomatous eyes) were scanned to determine the RNFL thickness measurements using the Stratus OCT. Measurements were obtained twice during the same day. The standard deviation (SD) was used to compare the variability in RNFL thickness measurements of the normal subjects to that of the glaucomatous patients. Multivariate regression analysis was used to evaluate which covariates were independent predictors of SD in overall mean RNFL thickness.

Results

The mean SD of all RNFL thickness measurements was larger in the glaucoma group except in one sector. In the multivariate regression analysis, the average signal strength (SS) and the relative SS change (difference in SS between initial and repeat scans, divided by initial SS) were independent predictors of the SD in the RNFL thickness measurements (partial R² = 0.018, 0.013; p = 0.016, 0.040, respectively).

Conclusions

Glaucomatous eyes tend to be more variable than normal eyes in RNFL thickness measurement using the Straus OCT. The average SS and the relative SS changes appear to correlate with the variability in RNFL thickness measurement. Therefore, the results of the RNFL analysis should not be interpreted independently of these factors.     

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.