Sectoral Retinal Nerve Fiber Layer Research Articles

Retinal Nerve Fiber Layer Imaging with Spectral-Domain Optical Coherence Tomography: A Variability and Diagnostic Performance Study

To evaluate and compare the retinal nerve fiber layer (RNFL) measurement variability, diagnostic sensitivity and specificity for glaucoma detection, and strength of the structure-function association obtained with a spectral-domain optical coherence tomography (OCT) device (Cirrus HD-OCT; Carl Zeiss Meditec, Inc., Dublin, CA) and a time-domain OCT device (Stratus OCT; Carl Zeiss Meditec, Inc.). Prospective, cross-sectional study. Ninety-seven normal subjects and 83 glaucoma patients. One eye from each subject was imaged with Cirrus HD-OCT and Stratus OCT. Sixteen and 31 normal eyes were selected randomly to evaluate intravisit repeatability and intervisit reproducibility, respectively. The agreement of RNFL measurements was evaluated with Bland-Altman plots. The diagnostic sensitivity and specificity was examined with the area under the receiver operating characteristic curve (AUC). The association between average RNFL thickness and visual field sensitivity was evaluated with a second-order regression model. Retinal nerve fiber layer measurement variability, AUC, and coefficient of determination (R(2)). The intravisit repeatability of Cirrus HD-OCT ranged between 5.12 and 15.02 mum, and the intervisit reproducibility ranged between 4.31 and 22.01 mum. The intervisit variabilities of sectoral and average RNFL thicknesses were lower in Cirrus HD-OCT compared with Stratus OCT with significant differences at 1, 3, 4, and 8 to 11 o'clock (P< or =0.021). There were proportional biases of RNFL measurements between the 2 OCT devices. The difference of RNFL thicknesses increased with the means. The average (AUC, 0.962 for Cirrus HD-OCT and 0.956 Stratus OCT), superior (AUC, 0.963 and 0.950, respectively), and inferior (AUC, 0.949 and 0.931, respectively) RNFL thicknesses demonstrated the greatest AUCs in both OCT devices with no significant difference detected between the respective measurements (P> or =0.120). The strength of the structure-function association was comparable between Cirrus HD-OCT (R(2) = 0.580) and Stratus OCT devices (R(2) = 0.623; P = 0.918). Although the diagnostic performance and the strength of the structure-function association were comparable between Cirrus HD-OCT and Stratus OCT RNFL measurements, Cirrus HD-OCT demonstrated lower measurement variability compared with Stratus OCT with significant differences at 1, 3, 4, and 8 to 11 o'clock. The poor agreement was likely related to the different inherent characteristics of the 2 OCT systems.

Effects of Age on Optical Coherence Tomography Measurements of Healthy Retinal Nerve Fiber Layer, Macula, and Optic Nerve Head

To determine the effects of age on global and sectoral peripapillary retinal nerve fiber layer (RNFL), macular thicknesses, and optic nerve head (ONH) parameters in healthy subjects using optical coherence tomography (OCT). Retrospective, cross-sectional observational study. A total of 226 eyes from 124 healthy subjects were included. Healthy subjects were scanned using the Fast RNFL, Fast Macula, and Fast ONH scan patterns on a Stratus OCT (Carl Zeiss Meditec, Dublin, CA). All global and sectoral RNFL and macular parameters and global ONH parameters were modeled in terms of age using linear mixed effects models. Normalized slopes were also calculated by dividing the slopes by the mean value of the OCT parameter for interparameter comparison. Slope of each OCT parameter across age. All global and sectoral RNFL thickness parameters statistically significantly decreased with increasing age, except for the temporal quadrant and clock hours 8 to 10, which were not statistically different from a slope of zero. Highest absolute slopes were in the inferior and superior quadrant RNFL and clock hour 1 (superior nasal). Normalized slopes showed a similar rate in all sectors except for the temporal clock hours (8-10). All macular thickness parameters statistically significantly decreased with increasing age, except for the central fovea sector, which had a slight positive slope that was not statistically significant. The nasal outer sector had the greatest absolute slope. Normalized macular slope in the outer ring was similar to the normalized slopes in the RNFL. Normalized inner ring had shallower slope than the outer ring with a similar rate in all quadrants. Disc area remained nearly constant across the ages, but cup area increased and rim area decreased with age, both of which were statistically significant. Global and regional changes caused by the effects of age on RNFL, macula, and ONH OCT measurements should be considered when assessing eyes over time. Proprietary or commercial disclosure may be found after the references.

Agreement between spectral-domain and time-domain OCT for measuring RNFL thickness

Background/aims:To evaluate spectral-domain (SD) optical coherence tomography (OCT) reproducibility and assess the agreement between SD-OCT and Time-Domain (TD) OCT retinal nerve fibre layer (RNFL) measurements.Methods:Three Cirrus-SD-OCT scans and one Stratus-TD-OCT...

Structural and Functional Relationships in Glaucoma Using Standard Automated Perimetry and the Humphrey Matrix

PurposeTo evaluate and compare correlations between structural and functional loss in glaucoma as assessed by optical coherence tomography (OCT), scanning laser polarimetry (GDx VCC, as this was the model used in this study), standard automated perimetry (SAP), and the Humphrey Matrix (Matrix).MethodsNinety glaucomatous eyes identified with SAP and 112 eyes diagnosed using Matrix were independently classified into six subgroups, either S1/M1 (MD>-6dB), S2/M2 (-12<MD<-6dB) or S3/M3 (MD<-12dB), according to the mean deviation (MD) of each test. Average and sectoral retinal nerve fiber layer (RNFL) thickness and percentage of abnormal classifications using the internal normative databases of OCT and GDx VCC were compared among the six subgroups.ResultsIn the SAP subgroups, RNFL thickness values obtained by OCT in the nasal and temporal quadrants and the inferior averages of GDx VCC did not differ between the S1 and S2 subgroups (p=0.137, 0.738 and 0.149, respectively). In the Matrix subgroups, no measurement parameters differed between the M1 and M2 groups except for the overall mean and average inferior RNFL thickness given by OCT and the NFI values of GDx VCC (p=0.013, 0.016 and 0.029, respectively). When abnormal classifications were compared, all measurement parameters, without exception, were significantly different in both the SAP and the Matrix subgroups.ConclusionsSAP subgroups showed a good correlation of structural and functional defects when assessed using OCT and GDx VCC. These correlations were weaker in the Matrix subgroups, especially in the early stages of glaucoma.

Regional Relationship Between Retinal Nerve Fiber Layer Thickness and Corresponding Visual Field Sensitivity in Glaucomatous Eyes

To establish the structure-function relationship between peripapillary retinal nerve fiber layer (RNFL) thickness and visual field (VF) test points in standard automated perimetry. We included 213 eyes with open-angle glaucoma and VF loss in this cross-sectional study. Correlations between individual VF sensitivity at 52 test points and peripapillary RNFL thickness divided into 16 sectors were calculated. The RNFL thickness was measured by Stratus optical coherence tomography. A new VF cluster map corresponding to RNFL sectors was generated by grouping the VF test points with the highest relation to each RNFL sector. The VF sensitivity at each test point was significantly correlated with the sectoral RNFL thickness. The highest coefficient of determination (R(2)) for a superotemporal RNFL sector and VF sensitivity at an inferotemporal test point (9 degrees temporal and 15 degrees inferior from the center) in standard automated perimetry was 0.500 (P < .001). Clustered VF test points most highly related to the RNFL sectors were asymmetrically located between the upper and lower hemifields. A newly developed map revealed significant structure-function relationships. We describe an association between VF sensitivity at test points and sectoral RNFL thickness. Nine clustered VF test points corresponding to 9 RNFL regions were demonstrated from the structure-function relationships.

Effect of Improper Scan Alignment on Retinal Nerve Fiber Layer Thickness Measurements Using Stratus Optical Coherence Tomograph

Misalignment of the Stratus optical coherence tomograph scan circle placed by the operator around the optic nerve head (ONH) during each retinal nerve fiber layer (RNFL) examination can affect the instrument reproducibility and its theoretical ability to detect true structural changes in the RNFL thickness over time. We evaluated the effect of scan circle placement on RNFL measurements. Observational clinical study. Sixteen eyes of 8 normal participants were examined using the Stratus optical coherence tomograph Fast RNFL thickness acquisition protocol (software version 4.0.7; Carl Zeiss Meditec, Dublin, CA). Four consecutive images were taken by the same operator with the circular scan centered on the optic nerve head. Four images each with the scan displaced superiorly, inferiorly, temporally, and nasally were also acquired. Differences in average and sectoral RNFL thicknesses were determined. For the centered scans, the coefficients of variation (CV) and the intraclass correlation coefficient for the average RNFL thickness measured were calculated. When the average RNFL thickness of the centered scans was compared with the average RNFL thickness of the displaced scans individually using analysis of variance with post-hoc analysis, no difference was found between the average RNFL thickness of the nasally (105.2 microm), superiorly (106.2 microm), or inferiorly (104.1 microm) displaced scans and the centered scans (106.4 microm). However, a significant difference (analysis of variance with Dunnett's test: F=8.82, P<0.0001) was found between temporally displaced scans (115.8 microm) and centered scans. Significant differences in sectoral RNFL thickness measurements were found between centered and each displaced scan. The coefficient of variation for average RNFL thickness was 1.75% and intraclass correlation coefficient was 0.95. In normal eyes, average RNFL thickness measurements are robust and similar with significant superior, inferior, and nasal scan displacement, but average RNFL thickness is greater when scans are displaced temporally. Parapapillary scan misalignment produces significant changes in RNFL assessment characterized by an increase in measured RNFL thickness in the quadrant in which the scan is closer to the disc, and a significant decrease in RNFL thickness in the quadrant in which the scan is displaced further from the optic disc.

Longitudinal analysis of retinal changes after branch retinal artery occlusion using optical coherence tomography

Background Branch retinal artery occlusion (BRAO) causes inner retinal ischemia leading to permanent inner retinal dysfunction and visual field loss in affected retinal sectors. Optical coherence tomography (OCT) offers a novel way to evaluate in vivo retinal morphologic changes in BRAO in both acute and longitudinal phases. This case report describes OCT findings in BRAO at acute presentation and at follow-up, including the longitudinal evaluation of retinal and peripapillary retinal nerve fiber layer (RNFL) thickness. Case report A 58-year-old white man with an acute branch retinal artery occlusion was examined by OCT at initial presentation and at 2, 4, and 8 months. At initial presentation, OCT line scan showed thickening and hyper-reflectivity of the inner retina with shadowing of photoreceptor and retinal pigment epithelial layers. At 2 months, hyper-reflectivity and thickening were reduced. At 4 months, the inner retina showed no hyper-reflectivity and was attenuated. Peripapillary RNFL thickness was reduced in corresponding sectors. Findings at the 8-month follow-up were unchanged from the 4-month visit. Conclusions OCT provides useful information regarding the evolution of inner retinal attenuation in BRAO. Differential diagnosis of sectoral peripapillary RNFL thinning should include previous BRAO.

Changes in RNFL Thickness According to the Myopia in Patients with Glaucoma and Ocular Hypertension

Purpose: To evaluate the changes in retinal nerve fiber layer (RNFL) thickness according to the degree of myopia in patients with glaucoma and ocular hypertension. Methods: Ninety-eight patients (165 eyes) diagnosed with glaucoma or ocular hypertension underwent optical coherence tomography (OCT) and scanning laser polarimetry using variable corneal compensation (GDx-VCC) to analyze the correlation between the degree of myopia and the thickness of the RNFL. A partial correlation coefficient analysis was performed to adjust for various factors such as age, laterality, intraocular pressure, and the mean deviation from visual field test, which can influence the RNFL thickness. Results: The average, nasal, superior, and inferior sectorial RNFL thicknesses measured by OCT significantly decreased with increasing myopia (p

Preperimetric Glaucoma Assessment With Scanning Laser Polarimetry (GDx VCC)

To evaluate the capability of the GDx VCC nerve fiber analyzer to detect preperimetric glaucoma across 12 retinal nerve fiber layer (RNFL) peripapillary sectors. Data were obtained in a cross-sectional, hospital clinic-based study; 699 eyes from 699 glaucoma suspects were enrolled in this protocol. All subjects underwent ophthalmologic examination, static automated perimetry [Humphrey 24-2 Swedish interactive threshold algorithm (SITA) Standard], optic nerve stereoscopic photographs, red-free digital RNFL photographs and GDx VCC examination. Group S included 283 normal eyes and 39 preperimetric glaucoma eyes with RNFL superior or diffuse defects in the fiber layer photographs. Group I included 324 normal subjects and 24 with preperimetric glaucoma eyes with RNFL inferior or diffuse defects in fiber layer photographs. Mean values of the area under the curve (AUC) for receiver operating characteristic analysis for inferior average (Inf Avg), temporal-superior-nasal-inferior temporal average (TSNIT Avg), superior average (Sup Avg), and the nerve fiber indicator were significantly less in the eyes with RNFL defects than the control group compared with the AUC for thickness at hour 12 and at hour 6 calculated from the RNFL sector density. The AUC for receiver operating characteristic analysis of the new parameters improved by 12% with respect to the best GDx VCC standard values. Our results confirm that the 12 sector divisions of the GDx VCC have better diagnostic reliability in preperimetric glaucoma, and are able to improve the discrimination capability between normal and early damaged RNFLs.

Relationship Between Patterns of Visual Field Loss and Retinal Nerve Fiber Layer Thickness Measurements

To investigate the association between patterns of visual field (VF) loss and retinal nerve fiber layer (RNFL) thickness measurements. Observational cross-sectional study. One hundred twenty-one glaucoma patients and 65 healthy subjects from the Diagnostic Innovations in Glaucoma Study (DIGS) were included. All glaucoma patients had repeatable abnormal VFs and scanning laser polarimetry (SLP) RNFL thickness measurements. RNFL measurements were obtained from 16 equal parapapillary sectors. Patterns of VF loss were classified as arcuate, partial arcuate, nasal step, or paracentral in each VF hemifield. Logistic regression analysis was performed to determine which RNFL sectors were associated with each VF pattern. The ability of SLP to discriminate between eyes with different VF patterns and healthy eyes using receiver operating characteristic (ROC) curve analyses also was investigated. VF patterns in the superior hemifield were significantly associated with RNFL sectors in the temporal inferior hemiretina (P < .05). ROC curve areas for discrimination between eyes with different VF patterns and healthy eyes ranged from 0.85 to 0.95. VF patterns in the inferior hemifield were most strongly associated with temporal superior RNFL sectors (P < .05). ROC curve areas for discrimination between different VF patterns and healthy eyes ranged from 0.73 to 0.98. SLP could discriminate between apparently unaffected VF hemifields in glaucoma eyes and VF hemifields in healthy eyes. Parapapillary RNFL thickness was topographically related to patterns of VF loss. SLP can differentiate between apparently unaffected VF hemifields in glaucoma eyes and normal VF hemifields in healthy eyes.

Korrelation zwischen glaukomatösen Halbfeldskotomen und Messungen der Nervenfaserschichtdicke mittels Scanning-Laser-Polarimetrie

The purpose of the present study was to investigate wether a reduction of the retinal nerve fiber layer (RNFL) in patients with hemifield scotoma can be measured with scanning laser polarimetry and wether regional RNFL parameters can be correlated with the corresponding visual field indices. We included one eye from each of 40 normal subjects and one eye from each of 40 glaucoma patients. Automated perimetry was performed and the RNFL was analyzed. HMD values obtained by white-white (W/W) and blue-yellow (B/Y) perimetry failed to correlate significantly with most of the corresponding RNFL parameters obtained with the GDx. Significant correlations were only shown for the inferior HMD (W/W and B/Y) and the superior ratio, superior average, and deviation superior. Furthermore, we found a high correlation between differences of upper and lower GDx parameters and differences of upper and lower visual field indices of W/W and B/Y perimetry. Scanning laser polarimetry can detect differences in RNFL sectors in patients with functional hemifield differences and carries the potential to detect changes in RNFL thickness at an early stage.

Predicting Subsequent Visual Field Loss in Glaucomatous Subjects With Disc Hemorrhage Using Retinal Nerve Fiber Layer Polarimetry

To predict progression of visual field loss after an episode of disc hemorrhage in glaucoma patients on the basis of retinal nerve fiber layer (RNFL) GDx polarimetry measurements analyzed by wavelet-Fourier analysis (WFA). Retrospective GDx data from 16 subjects (10 progressors and 6 non-progressors based on visual fields) obtained near the time of disc hemorrhage were analyzed to predict which patients would have visual field progression. Polarimetry scans throughout a follow-up period (31 months average) were also analyzed to compare field progression to RNFL thickness change after the hemorrhage. Mean RNFL thickness inferred from the polarimetry data at sixteen 22.5 degrees sectors at distances of 1.6, 1.7, and 1.8 disc diameters were used. Data were analyzed by applying to appropriate regions of disc hemorrhage patients a structural analysis (WFA) we had developed previously. A linear discriminant function (Fischer) was produced and a leave-one-out method using separate training and test data was used to assure validity of the results. Patients who subsequently progressed were successfully predicted with moderate success (sensitivity / specificity was 0.77 / 0.88 with ROC area = 0.858). A separate analysis comparing pre- and post-hemorrhage RNFL sector thickness revealed clear evidence of RNFL thinning at the inferior and superior sectors before progression of visual field. The thinning of RNFL thickness was not restricted to regions corresponding to the location of the hemorrhage. Wavelet-Fourier analysis can differentiate progressors from non-progressors with moderate accuracy. Comparison to a prior study of this same cohort emphasizes that relatively small regions must be considered (as opposed to larger quadrants) to see these significant changes in RNFL.

Short-wavelength automated perimetry results are correlated with optical coherence tomography retinal nerve fiber layer thickness measurements in glaucomatous eyes

Purpose To determine the relationship between retinal nerve fiber layer (RNFL) thickness measured using optical coherence tomography (OCT) and short wavelength–sensitive visual function measured using short-wavelength automated perimetry (SWAP). Design Retrospective observational case series. Methods Subjects were recruited from the longitudinal University of California, San Diego, Diagnostic Innovations in Glaucoma Study and included 29 glaucoma patients with OCT imaging and reliable SWAP visual field (VF) testing within a 6-month window. Main outcome measures Correlations between deviation from normal (thinner than 97.5% of normal) RNFL measurements taken at 30° sectors (12 sectors described as clock hours) and SWAP average pattern deviation within 21 VF zones were determined. The number of OCT-measured RNFL sectors outside of normal limits and the number of VF zones outside of normal limits also were compared. Results The OCT nerve fiber layer thickness was outside of the normal limits in at least 1 sector in 26 (89.6%) patients. Twenty-eight (96.5%) patients had at least 1 SWAP VF zone outside of normal limits. Optical coherence tomography sectors 6-o'clock, 7-o'clock, and 8-o'clock (inferior and inferotemporal) and SWAP VF zones 13, 14, and 16 (superior hemifield central and arcuate areas) were the most frequently damaged. In general, the strongest R 2 associations were between inferior and inferior temporal RNFL sectors (e.g., 6-o'clock, 7-o'clock) and superior nasal/arcuate VF zones (e.g., zones 13, 14, 15) and between superior and superior temporal RNFL sectors (e.g., 12-o'clock, 11-o'clock) and inferior central and arcuate VF zones (e.g., zones 5, 6, 7) ( R 2 range = 24.3%–37.3%, all Ps ≤ 0.005). Most nonsignificant associations were found between superior RNFL sectors and superior VF zones. Conclusion Retinal nerve fiber layer thickness measured with OCT is topographically correlated with glaucomatous VF defects measured with SWAP.