Quadrant Retinal Nerve Fiber Layer Research Articles

Application of optical coherence tomography in glaucoma suspect eyes

Purpose: The aim of the study was to compare the optical coherence tomography (OCT) parameters of the optic nerve head (ONH) and retinal nerve fibre layer (RNFL) and to identify which measurements are best able to differentiate between normal and glaucoma suspect eyes.Methods: The study included 27 eyes with ocular hypertension (OHT), 33 eyes with pre‐perimetric glaucoma (PG), 30 perimetrically unaffected eyes of patients with glaucoma in the fellow eye (FE) and 58 eyes of age‐matched normal volunteers. All subjects underwent a complete eye examination with standard automated perimetry, optic disc photography and OCT imaging. Peripapillary ‘fast RNFL thickness scans’ and ‘fast optic disc scans’ were performed with time‐domain OCT. The ONH and RNFL parameters were compared among the four study groups. The ONH and RNFL parameters were examined alone and then combined via four linear discriminant functions (LDF): LDF 1, the optimal combination of ONH parameters; LDF 2, the optimal combination of RNFL parameters; LDF 3, the optimal combination of both ONH and RNFL parameters; and LDF 4, the optimal combination of the best 11 parameters. The areas under the receiver operating curves (AUC) and the sensitivity at fixed specificity of at least 80 and 95 per cent were calculated for single parameters and LDF combinations and then compared. The best 11 parameters were selected based on their AUC values.Results: Comparative analysis of OCT parameters revealed statistically significant differences in all seven ONH parameters in both PG and FE groups (and only in one ONH measurement in the ocular hypertensive group) when compared with normal eyes. Most of the RNFL parameters demonstrated statistically significant differences in all of the study groups when compared with the control group. The max‐min parameter (0.835), inferior quadrant (0.833) and average RNFL thickness (0.829) obtained the highest AUC values in the whole glaucoma suspect group. The rim area had the best diagnostic accuracy among the ONH parameters (AUC = 0.817). The AUC values of the four LDF were: 0.825 (LDF 1), 0.882 (LDF 2), 0.902 (LDF 3) and 0.888 (LDF 4). Statistically significant differences were found between the AUC values of the single best ONH and RNFL parameters and LDF 3 and LDF 4.Conclusions: In the present study, RNFL parameters presented with better discriminatory abilities than ONH parameters in the OHT and FE groups. The ONH parameters demonstrated better diagnostic precision in differentiating between PG and normal eyes. The average RNFL thickness, max–min parameter and inferior quadrant RNFL thickness had the best abilities among single OCT measurements for discriminating between glaucoma suspect (including all ocular hypertensive, PG and FE eyes) and normal eyes. The combination of RNFL parameters only or both ONH and RNFL parameters, using linear discriminant analysis, provided the best classification results, improving the diagnostic accuracy of the instrument.

The effect of software upgrade on optical coherence tomography measurement of the retinal nerve fiber layer thickness

Purpose:To determine the effect of software upgrades on retinal nerve fiber layer (RNFL) thickness measurements taken by spectral domain optical coherence tomography (SD-OCT).Methods:Eighty normal eyes (40 patients) were scanned for RNFL thickness measurements using Spectralis (Heidelberg Engineering, Heidelberg, Germany) SD-OCT. Scan analysis was performed using version 4.0 software and then reanalyzed with version 5.1.3. Student paired t testing and Pearson's correlation coefficient were used for statistical analysis.Results:Average and quadrant RNFL thicknesses generated using version 4.0 and 5.1.3 software on Spectralis demonstrated high correlation (r = 0.955-0.998). Average RNFL thickness using version 4.0 was 0.08μm thinner than version 5.1.3 (p = 0.409). Quadrant RNFL differences ranged from -0.26 to +0.97μm (p = 0.146-0.915). Segmentation errors were reduced 33% after the upgrade.Conclusion:Minor RNFL thickness changes may occur after software upgrades in Spectralis OCT. The differences did not reach statistical significance but segmentation errors were improved.

Evaluation of retinal nerve fiber thickness in myopic eyes by optical coherence tomography

The purpose of this study was to evaluate the relationship between retinal nerve fiber layer thickness measured by optical coherence tomography and the axial length/refractive error in myopic eyes. Medical records of 30 healthy male subjects and 50 male patients with miyopia (spherical equivalent between -1.0 D and -8.75 D) were analyzed retrospectively in the study. Spherical equivalent, axial length, mean and four quadrant retinal nerve fiber layer thickness measurements of one eye were recorded in all patients. Retinal nerve fiber layer thickness measurements were compared between the two groups. Relationship between axial length/spherical equivalent and retinal nerve fiber layer thickness was analyzed. The mean axial length in the control and myopic groups was 23.36±0.65 mm and 25.58±1.50 mm, respectively (t=7.59, p

Age and Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography

PurposeTo evaluate the association between age and peripapillary retinal nerve fiber layer (RNFL) thickness measured by Cirrus high-definition (HD) spectral domain optical coherence tomography (OCT) in healthy Korean subjects.MethodsA total of 302 eyes from 155 healthy Korean subjects (age range, 20 to 79 years) underwent RNFL thickness measurements using the Cirrus HD-OCT. Average, quadrant, and clock-hour RNFL thickness parameters were analyzed in terms of age using linear mixed effect models.ResultsAverage RNFL demonstrated a slope of -2.1 µm per decade of age (p < 0.001). In quadrant analysis, superior (-3.4 µm/decade, p < 0.001) and inferior (-2.9 µm/decade, p < 0.001) quadrants showed steeper slopes, whereas temporal (-1.1 µm/decade, p < 0.001) and nasal (-1.0 µm/decade, p < 0.001) quadrants revealed shallower slopes. Among the 12 clock-hour sectors, clock hours 6 (-4.5 µm/decade, p < 0.001) and 1 (-4.1 µm/decade, p < 0.001) showed the greatest tendency to decline with age; RNFLs of the 3 (-0.2 µm/decade, p = 0.391) and 4 (-0.6 µm/decade, p = 0.052) o'clock hour sectors did not show significant decay.ConclusionsRNFL thickness was associated with age, especially in superior and inferior areas. The topographic distribution of correlation between age and RNFL thickness was not uniform.

Evaluation of the Optic Nerve and Retinal Nerve Fiber Layer in Myopic Individuals

Clinical discrimination between myopic tilted optic discs and glaucomatous optic neuropathy is often challenging, especially when considering that myopia is a risk factor for the development of glaucoma. Myopic tilted discs are usually larger than average, with associated relative cupping and thinner neuroretinal rim tissue. Histopathologic study has revealed thinner parapapillary retinal tissue in these eyes. Optical coherence tomography (OCT)-measured average retinal nerve fiber layer (RNFL) thickness has been found to decrease with longer axial length and higher myopic refractive error. Parapapillary RNFL quadrant and clock-hour analyses result in a higher false-positive rate in myopic eyes. Careful slit-lamp examination, quality baseline stereoscopic disc photographs, and frequent serial visual field testing are essential to the follow-up of myopic individuals with suspected glaucoma. A novel diagnostic parameter, OCT-derived ganglion cell analysis, may prove to be useful in the diagnosis and follow-up of these individuals.

Misalignments in the Retinal Nerve Fiber Layer Evaluation Using Cirrus High-definition Optical Coherence Tomography

To evaluate the frequency and characteristics of misalignments (MAs) in the retinal nerve fiber layer (RNFL) analysis protocol of spectral-domain optical coherence tomography (Cirrus) and determine factors associated with MAs. Three hundred eyes (162 normal and 138 glaucomatous eyes) were included in this cross-sectional study. The MAs were considered limited when they affected only part of the scan line, and complete (CMA) when they were observed in the entire scan line. A subgroup (153 cases) with repeated scans was analyzed to compare the RNFL thicknesses in the scans with and without CMAs. Two hundred ninety-nine limited MAs were found in 140 eyes (46.7%) and 151 CMAs were found in 91 eyes (30.3%). The frequency and number of CMAs were significantly related to age (P<0.05). Seventy-two CMAs were in the measurement ring in 48 eyes, more frequently in the 3 and 9-o'clock positions (P=0.001) and the horizontal quadrants (P=0.001). Among the repeated scans, the number of cases with CMAs was similar to the first scan (P=0.32). No significant differences were found in global or quadrant RNFL thickness between scans with and without CMAs. CMAs were present in the first or second scans in about 30% of cases and were related to older age. CMAs were more frequently in horizontal meridians and quadrants. No differences in RNFL thickness were found between scans with and without CMAs in the same patients. Scans with CMAs in the measurement ring can be considered in the RNFL evaluation.

Retinal nerve fiber layer and macular inner retina measurements by spectral domain optical coherence tomograph in Indian eyes with early glaucoma

To compare the diagnostic abilities of peripapillary retinal nerve fiber layer (RNFL) and macular inner retina (MIR) measurements by spectral domain optical coherence tomography (SD-OCT) in Indian eyes early glaucoma. In an observational, cross-sectional study, 125 eyes of 64 normal subjects and 91 eyes of 59 early glaucoma patients underwent RNFL and MIR imaging with SD-OCT. Glaucomatous eyes had characteristic optic nerve and RNFL abnormalities and correlating visual field defects and a mean deviation of better than or equal to -6 dB on standard automated perimetry. Areas under the receiver operating characteristic curves (AUC), sensitivities at a fixed specificity and likelihood ratios (LRs) were estimated for all RNFL and MIR parameters. The AUCs for the RNFL parameters ranged from 0.537 for the temporal quadrant thickness to 0.821 for the inferior quadrant RNFL thickness. AUCs for the MIR parameters ranged from 0.603 for the superior minus inferior MIR thickness average to 0.908 for ganglion cell complex focal loss volume (GCC-FLV). AUC for the best MIR parameter (GCC-FLV) was significantly better (P<0.001) than that of the best RNFL parameter (inferior quadrant thickness). The sensitivities of these parameters at high specificity of 95%, however, were comparable (52.7% vs58.2%). Evaluation of the LRs showed that outside normal limits results of most of the RNFL and MIR parameters were associated with large effects on the post-test probability of disease. MIR parameters with RTVue SD-OCT were as good as the RNFL parameters to detect early glaucoma.

Retinal nerve fiber layer thickness measured by

AbstractPurpose Our study aims to assess retinal nerve fiber layer (RNFL) thickness in patients affected by schizophreniaMethods Ten schizophrenic patients were enrolled.They were compared with 10 age‐matched controls. In all subjects, optic nerve head measurements, peripapillary RNFL thickness, macular thickness and volume were measured by optical coherence tomography.Results Schizophrenic patients showed an statistically significant reduction of the overall RNFL thickness compared with those values observed in control eyes. We also observed reduced peripapillary RNFL thickness in nasal quadrant in schizophrenic patients when compared with controls. The remaining peripapillary RNFL quadrants, macular thickness and volume did not reveal differences between both groups. No statistically significant differences were observed between control group and schizophrenia patients with regard to ONH measurements, macular thickness and volume.Conclusion Schizophrenia patients had a reduction of peripapillary RNFL thickness evaluated by OCT. To our knowledge, neither reduced RNFL thickness nor macular thickness and volume have been previously documented in patients diagnosed with schizophrenia. These findings suggest that neuronal degeneration could be present in the retina of schizophrenic patients as previously observed in neurodegenerative disorders.

P.1.f.002 The effects of early post-natal treatment with ketamine on learning, memory and nociception in rats

To assess, with optical coherence tomography (OCT), any changes in peripapillary retinal nerve fiber layer (RNFL) thickness in glaucoma patients after reduction of intraocular pressure (IOP).Prospective observational case series.Twenty-one eyes of 21 glaucoma patients who underwent medical or surgical intervention to lower IOP.Patients with elevated IOP underwent fast peripapillary RNFL measurements with the Stratus OCT (model 3000, software version 4.04; Carl Zeiss Meditec, Dublin, CA) before and after the IOP was lowered by medical or surgical therapy.Changes in overall and quadrant RNFL thickness with respect to change in IOP.The OCT scans were performed before intervention (range, 0–38 days before; mean±standard deviation [SD], 9.8±9.3 days) and after intervention (range, 32–74 days; mean±SD, 46.8±11.2 days) to measure peripapillary RNFL thickness. Mean IOP (mean±SD) decreased from 31.5±8.2 mmHg to 12.8±4.6 mmHg with the intervention (P<0.001). Twenty of 21 eyes had an IOP reduction of more than 30%. There was no significant change in the overall RNFL thickness associated with the lowering of IOP (mean±SD, 1.02±10.3 μm; P = 0.653). Quadrant analysis did not show a significant change in the RNFL thickness of any of the 4 quadrants (superior, −1.71±14.5 μm, P = 0.593; inferior, 2.38±16.8 μm, P = 0.523; temporal, 2.19±9.50 μm, P = 0.303; and nasal, 1.24±12.5 μm, P = 0.655). No relationship was found between any of the changes in OCT parameters or percent change in OCT parameters and the extent of IOP reduction, or whether IOP was lowered medically or surgically, with or without adjusting for preintervention OCT measurements as an indication of disease severity (P values ranged from 0.331 to 0.985).No significant change in the RNFL thickness was associated with the lowering of IOP by medical or surgical therapy, as measured by OCT.

Effects of Changing Operators and Instruments on Time-Domain and Spectral-Domain OCT Measurements of Retinal Nerve Fiber Layer Thickness

To determine the amount of interoperator and interinstrument variability introduced into retinal nerve fiber layer (RNFL) thickness measured with Stratus OCT and Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) in normal and glaucomatous eyes. Thirty-seven eyes from 37 subjects (20 normal and 17 with glaucoma) were included in the study. Each eye was scanned with one Stratus OCT and one Cirrus OCT by two operators. The eyes were then scanned with a different Stratus OCT and Cirrus OCT by one of the operators. Average, quadrant, and clock-hour RNFL measurements were compared between operators and between instruments after determining the proportion of variance due to subjects, operators, and instruments by means of variance component analysis. Significant differences were observed between Stratus OCT instruments, but not between Cirrus OCT instruments, in average (P = .01), inferior (P = .006), and nasal (P < .001) quadrant RNFL thickness in glaucomatous eyes. Interoperator differences in RNFL thickness measured with both types of instruments were non-significant. The interoperator variability ranged from 0% to 1% on Stratus OCT and was 0% on Cirrus OCT, whereas the interinstrument variability ranged from 0% to 3% for Stratus OCT and from 0% to 1% for Cirrus OCT. The interoperator variability of RNFL thickness measured with Stratus OCT and Cirrus OCT, as well as the interinstrument variability of measurements obtained with Cirrus OCT, are non-significant. However, there is significant variability between RNFL measurements performed on two different Stratus OCT instruments.

β-Zone Parapapillary Atrophy and the Rate of Retinal Nerve Fiber Layer Thinning in Glaucoma

To evaluate whether β-zone parapapillary atrophy (PPA) is associated with the rate of retinal nerve fiber layer (RNFL) thickness change as assessed by trend-based analysis using time-domain optical coherence tomography (OCT). This retrospective cohort study included 202 glaucomatous eyes that were observed for ≥3 years with serial OCTs and stereo disc photographs. Subjects were divided into two groups according to the presence (n = 144) or absence of β-zone PPA (n = 58). The rates of progressive thinning in global, quadrant, and clock-hour OCT RNFL thicknesses were determined using linear regression and compared between groups. Logistic regression analysis was used to determine the factors associated with the rate of global RNFL thinning. The mean rate for global RNFL thinning over time was -1.03 ± 1.50 μm/year. Eyes with β-zone PPA showed a significantly faster rate of RNFL thinning than did eyes without β-zone PPA in the inferior quadrant and 7 o'clock sector (values of P < 0.0029). Multivariate analysis showed significant influence of the presence of β-zone PPA and the percentage increase in the PPA to disc area ratio during the follow-up on the rate of OCT RNFL thinning (odds ratio [OR], 3.314, P = 0.007; OR, 2.894, P = 0.003, respectively). Glaucomatous eyes with β-zone PPA are at increased risk for progressive RNFL thinning.

Anatomic and functional correlation of frequency-doubling technology perimetry (FDTP) in multiple sclerosis

To study the correlation between the results of frequency-doubling technology perimetry (FDTP), visual function (visual acuity, contrast vision, standard automated perimetry (SAP)) and the thickness of the retinal nerve fiber layer (RNFL) throughout the course of multiple sclerosis (MS). Sixty-six eyes of thirty-three patients suffering from MS were chosen. Thirty-five eyes had a previous history of optic neuritis (ON group) and thirty-one eyes had no previous history of optic neuritis (non-ON group). The FDTP was performed with the N-30 screening program. Visual acuity was determined with the Snellen scale and the ETDRS (Early Treatment Diabetic Retinopathy Study) scale, the contrast vision with the Pelli-Robson and Sloan tests and the SAP with the Humphrey 750 perimeter. The thickness of the RNFL was measured using the STRATUS OCT™ optical coherence tomography (OCT). The visual field FDTP was divided into three sectors corresponding to the three SAP sectors and to the three RNFL quadrants of the OCT. The FDTP was significantly correlated (P<0.0001) to the contrast vision and to the SAP results (mean deviation (MD) and the different sectors among themselves). In the ON group, the MD FDTP was significantly correlated to the average RNFL thickness (r=0.44, P=0.0091). A decrease of 5 decibels (dB) of the MD FDTP corresponded to a decrease of 11.7 μm of the average RNFL thickness (Y=2.34×X+87.5). The strong correlation with SAP and RNFL confirms the value of FDTP in assessing optic nerve damage throughout the course of MS.

Trend-Based Analysis of Retinal Nerve Fiber Layer Thickness Measured by Optical Coherence Tomography in Eyes with Localized Nerve Fiber Layer Defects

To evaluate the rate of change in retinal nerve fiber layer (RNFL) thickness measured by optical coherence tomography (OCT) in eyes with stable and progressive localized RNFL defects and to investigate, in a trend-based approach, the diagnostic capability of OCT in the detection of progressive RNFL thinning. The study included 153 glaucomatous eyes with localized RNFL defects. The patients were divided into nonprogressors (n = 77) and progressors (n = 76) on the basis of an evaluation of serial red-free photographs. The rates of progressive thinning in global, quadrant, and clock-hour OCT RNFL thicknesses were determined, by linear regression, and were compared between groups. Areas under receiver operating characteristic curves and sensitivities at fixed specificities were calculated for each parameter. The rate of progressive RNFL thinning was significantly faster in progressors than in nonprogressors globally; in the inferior quadrant; in the 10, 11, 6, and 7 o'clock sectors; and in the affected quadrant and clock-hour sector thicknesses (all P ≤ 0.001). The rate of RNFL thinning in affected clock-hour sectors had the highest ability to discriminate between stable and progressive RNFL thinning with a sensitivity of 62% (95% confidence interval, 50%-73%) at a specificity ≥80%. Agreement between OCT and red-free photography was strongest when the criterion of -3.6 μm/year with P < 0.1 was used for each clock hour. The rate of OCT RNFL thinning was significantly greater in patients with progressive localized RNFL defects than in those with stable localized defects. The data suggest that trend-based analysis of OCT RNFL thickness may be useful in glaucoma progression analysis and may complement other diagnostic tests.

Inter-Device Agreement of Retinal Nerve Fiber Layer Thickness Measurements Using Spectral Domain Cirrus HD OCT

PurposeTo assess the inter-device agreement of peripapillary retinal nerve fiber layer (RNFL) thickness measurements by 2 spectral domain Cirrus HD optical coherence tomography (OCT) devices in healthy Korean subjects.MethodsEleven eyes of 11 healthy volunteers were enrolled in the present study. Each eye was scanned with the Optic Disc Cube 200 × 200 scan of 2 Cirrus HD OCT devices for peripapillary RNFL thickness calculation. The inter-device agreements of the 2 Cirrus HD OCTs for average, quadrant, and clock-hour RNFL thickness values were determined with Wilcoxon signed rank test, Friedman test, Cronbach's alpha (α), intraclass correlation coefficient (ICC), coefficient of variation (COV), and Bland-Altman plot.ResultsThe mean age of the participants was 25.82 ± 3.28 years and all had a 0.00 logarithm of the minimum angle of resolution of best-corrected visual acuity. The signal strengths of scans from the 2 Cirrus HD OCT were not significantly different (p = 0.317). The inter-device agreement of average RNFL thickness was excellent (α, 0.940; ICC, 0.945; COV, 2.45 ± 1.52%). However, the agreement of nasal quadrant RNFL thickness was not very good (α, 0.715; ICC, 0.716; COV, 5.72 ± 4.64%). Additionally, on the Bland-Atman plot, the extent of agreement of the 2 Cirrus HD OCTs for RNFL thickness was variable according to scanned sectors.ConclusionsThe inter-device agreement of 2 spectral domain Cirrus HD OCT devices for peripapillary RNFL thickness measurements was generally excellent but variable according to the scanned area. Thus, physicians should consider this fact before judging a change of RNFL thicknesses if they were measured by different OCT devices.

Comparison of Peripapillary Retinal Nerve Fiber Layer Thickness Measured by Spectral vs. Time Domain Optical Coherence Tomography

Purpose: To compare the peripapillary retinal nerve fiber layer (RNFL) thickness measured by spectral and time domain optical coherence tomography (OCT).Patients and Methods: One hundred and eighty-eight subjects (normal tension glaucoma, n = 80; primary open angle glaucoma, n = 49; healthy controls, n = 59) were included in this study. Peripapillary RNFL thickness was measured by an Optic Disc Cube 200 × 200 scan of the spectral domain Cirrus HD OCT and by a Fast RNFL scan of the time domain Stratus OCT. They were compared using linear regression (R2), Bland-Altman plots, weighted Kappa (Kw) coefficients, and areas under the receiver operating characteristic curve (AROC).Results: Except for the inferior quadrant, RNFL thickness measurements by Cirrus HD OCT were thinner than Stratus OCT (all p < 0.001); for the inferior quadrant, this tendency was vice versa (p = 0.043). Average RNFL thicknesses of the two OCTs showed a good correlation (R2, 0.852) but not excellent agreement (mean of difference, 4.0 μm; +1.96 SD, 10.7 μm; -1.96 SD, -18.6 μm). Regarding the probability codes, only the average RNFL thickness had almost perfect agreement (Kw, 0.983). In addition, Cirrus HD OCT had the largest AROC for the superior quadrant (0.795), but Stratus OCT had the largest AROC for average RNFL thickness (0.764) (p = 0.281).Conclusions: Except for the inferior quadrant, the average and quadrants RNFL thickness measured by the Cirrus HD OCT were thinner than the Stratus OCT. Regarding discriminating power for glaucoma detection, the Cirrus HD OCT was better than the Stratus OCT for the superior and inferior quadrant RNFL thicknesses but not for the average RNFL thickness.

Retinal nerve fiber layer thickness measured by optical coherence tomography in patients with schizophrenia: A short report

Background and Objectives: Our study aims to assess retinal nerve fiber layer (RNFL) thickness in patients affected by schizophrenia. Methods: Ten schizophrenic patients (mean age 39 +/- 13 years, best corrected visual acuity ≥ 20/20, refractive error between +/-2 diopters, and intraocular pressure <18 mmHg) were enrolled. They were compared with 10 age-matched controls. In all subjects, optic nerve head (ONH) measurements, peripapillary RNFL thickness, macular thickness and volume were measured by optical coherence tomography (OCT). Results: Schizophrenic patients showed an statistically significant reduction of the overall RNFL thickness (95+/-13 μm, range: 53-110) compared with those values observed in control eyes (103+/-8 μm, range: 88-119) (p = 0.047, Mann-Whitney U test). We also observed reduced peripapillary RNFL thickness in nasal quadrant in schizophrenic patients (75+/-17 μm, range: 41-111) when compared with controls (84+/-10 μm, range: 67-105) (p = 0.048, Mann-Whitney U test). The remaining peripapillary RNFL quadrants, macular thickness and volume did not reveal differences between both groups. No statistically significant differences were observed between the control group and schizophrenia patients with regard to ONH measurements, macular thickness and volume. Conclusions: Schizophrenia patients had a reduction of peripapillary RNFL thickness evaluated by OCT. To our knowledge, neither reduced RNFL thickness nor macular thickness and volume have been previously documented in patients diagnosed with schizophrenia. These findings suggest that neuronal degeneration could be present in the retina of schizophrenic patients as previously observed in neurodegenerative disorders.

Quantification of Retinal Nerve Fiber Layer Thickness in Normal Eyes, Eyes with Ocular Hypertension, and Glaucomatous Eyes with SD-OCT

To quantitatively evaluate and compare retinal nerve fiber layer (RNFL) thickness between normal eyes, eyes with ocular hypertension (OHT), and glaucomatous eyes in an Indian population using spectral domain optical coherence tomography (SD-OCT). Average and quadrant RNFL values were compared among three groups (66 normal eyes, 55 OHT eyes, and 51 glaucomatous eyes) and the discriminating power of each parameter was evaluated by calculating areas under receiver operator curves (AROCs). The mean RNFL thickness was 93.45 ± 16.9 μm in glaucomatous eyes, significantly less than in normal (112.48 ± 6.8 μm) and OHT (110.09 ± 10.9 μm) eyes. OHT eyes had significantly thinner RNFL thickness in the temporal quadrant (P = .006) than normal eyes. RNFL thickness in glaucomatous eyes differed significantly from normal eyes in most parameters except nasal quadrant (P = .1) and from OHT eyes in most parameters except temporal (P = .4) and nasal quadrants (P = .3). The parameter with the largest AROC to discriminate between OHT and normal eyes was temporal quadrant (0.65). Inferior quadrant RNFL thickness had the largest AROC (0.93) to distinguish between OHT and glaucomatous eyes and normal and glaucomatous eyes. SD-OCT identified differences in most parameters between eyes with glaucoma and normal eyes and also between eyes with glaucoma and OHT. Overlap of RNFL thickness between normal and OHT eyes limits the ability of this instrument to differentiate between normal and OHT subjects.

Acute Primary Angle Closure Attack Does Not Cause an Increased Cup-to-Disc Ratio

To determine if an increased cup-to-disc ratio (CDR) and retinal nerve fiber layer (RNFL) loss occur after acute primary angle closure (APAC). Prospective, observational case series. Twenty participants with unilateral APAC provided 20 affected eyes and 20 fellow eyes (controls) for analysis. After initial presentation, participants attended 3 further assessments over a 12-month period (visit 2, within 2 weeks; visit 3, 2-3 months; and visit 4, 6-12 months), in which they underwent the following investigations: Heidelberg Retinal Tomography (Heidelberg Engineering, Dossenheim, Germany), optical coherence tomography of the RNFL and macula, and automated perimetry. Cup-to-disc ratio, optic cup area, neuroretinal rim area, RNFL thickness, macular thickness, and volume. There was no change from visits 2 to 4 in CDR (0.46 ± 0.17 vs. 0.47 ± 0.20; P = 0.94), neuroretinal rim area (1.64 ± 0.55 vs. 1.64 ± 0.57; P = 0.96), or other optic nerve head parameters analyzed in eyes with APAC. The mean overall RNFL thickness decreased from 106.6 ± 17.9 μm to 92.9 ± 18.3 μm between visits 2 and 3 (P<0.01) in affected eyes. The superior quadrant RNFL thickness decreased from 134.8 ± 25.9 μm to 113 ± 25.7 μm (P<0.01), and the inferior quadrant RNFL thickness decreased from 139.1 ± 28.4 μm to 115.6 ± 24.9 μm (P<0.01). There was no significant change in macular thickness or volume. This study demonstrated that an increase in CDR does not occur after APAC that is treated promptly, although RNFL loss does occur.

Effect of signal strength on reproducibility of peripapillary retinal nerve fiber layer thickness measurement and its classification by time-domain optical coherence tomography

To assess the effect of signal strength (SS) on reproducibility of peripapillary retinal nerve fiber layer (RNFL) thickness measurement (measurement agreement) and its color-coded classification (classification agreement) by time-domain optical coherence tomography (OCT). Two consecutive Stratus OCT scans with the Fast RNFL protocol were performed in 658 participants. Intraclass correlations and the linear-weighted kappa coefficient were calculated as indicators of RNFL measurement and classification agreement in participants grouped according to the difference in SS between consecutive OCT scans (interscan SS difference). Groups with a larger interscan SS difference (= 2) had lower measurement agreement than those with a smaller interscan SS difference (0 or 1) for the temporal quadrant and total average RNFL. Classification agreement for the nasal quadrant was lower in the groups with a larger interscan SS difference (= 2) than in those with a smaller interscan SS difference. The tendency of SS to affect classification and measurement agreement remained similar in the group with thinner RNFL thickness (≤85 μm), but not in the group with thicker RNFL. Careful attention should be paid when comparing two or more OCT scans for RNFL thickness measurement or its color-coded classification as the agreement may be sensitive to SS differences.

Spectral-Domain Optical Coherence Tomography for Detection of Localized Retinal Nerve Fiber Layer Defects in Patients With Open-Angle Glaucoma

To evaluate and compare time-domain (Stratus) and spectral-domain (Cirrus; both Carl Zeiss Meditec, Dublin, California) optical coherence tomography (OCT) for the detection of localized retinal nerve fiber layer (RNFL) defects in patients with open-angle glaucoma. Patients with localized RNFL defects and age-matched normal control participants were consecutively enrolled from July 1 to December 31, 2008. Sixty-six eyes from 66 patients and 66 eyes from 66 normal controls were imaged with Stratus OCT (fast RNFL scan mode) and Cirrus OCT (optic disc cube mode). The ability to detect the RNFL defect by using quadrant clock-hour maps from both OCTs and a Cirrus OCT deviation map were compared with red-free RNFL photography, which is the criterion standard for visualizing RNFL defects. The Cirrus OCT deviation map exhibited significantly higher overall sensitivity (92.42%) in detecting the RNFL defects compared with the other maps, which were derived from a 3.46-mm-diameter peripapillary cross-sectional RNFL scan of both OCTs (P < .001). The Cirrus OCT quadrant map had a higher specificity; however, it was not statistically significant (P = .07). Compared with the other maps, the Cirrus OCT derivation map had the lowest cutoff angle for the width (10.69°) of the RNFL defect. The deviation map from Cirrus OCT was more sensitive in detecting RNFL defects than the clock-hour and quadrant maps derived from cross-sectional peripapillary RNFL measurements by Stratus and Cirrus OCTs. The ability to detect localized RNFL defects on clock-hour or quadrant RNFL maps did not significantly differ between Stratus OCT and Cirrus OCT.