Peripapillary Retinal Nerve Fiber Layer Thickness Measurements Research Articles

Diagnostic Ability of Fourier-Domain vs Time-Domain Optical Coherence Tomography for Glaucoma Detection

To compare retinal nerve fiber layer (RNFL) thickness assessments and the discriminating ability of Fourier-domain optical coherence tomography (FD-OCT) with that of time-domain optical coherence tomography (TD-OCT) for glaucoma detection. Prospective, nonrandomized, observational cohort study. Normal and glaucomatous eyes underwent complete examination, standard automated perimetry, optic disc photography, TD-OCT (Stratus OCT; Carl Zeiss Meditec, Dublin, California, USA), and FD-OCT (RTVue; Optovue Inc, Fremont, California, USA). One eye per subject was enrolled. Two consecutive scans were acquired using a 3.46-mm diameter scan with TD-OCT and a 3.45-mm diameter scan with FD-OCT. For each of 5 RNFL parameters, the area under the receiver operator characteristic curve was calculated to compare the ability of FD-OCT and TD-OCT to discriminate between normal and glaucomatous eyes. Fifty healthy persons (mean age, 65.3 +/- 9.9 years) and 50 glaucoma patients (mean age, 67.7 +/- 10.5 years) were enrolled. Average, superior, and inferior RNFL thickness measurements (in micrometers) were significantly (P < .01) greater with FD-OCT compared with TD-OCT in normal eyes (103.3 +/- 12.6 vs 96.3 +/- 10.7, 134.5 +/- 18.6 vs 113.9 +/- 16.3, and 129.7 +/- 16.9 vs 125.5 +/- 15.8, respectively) and glaucomatous eyes (P < .001; 77.6 +/- 17.6 vs 70.4 +/- 18.6, 108.0 +/- 26.8 vs 86.8 +/- 30.2, 82.2 +/- 3.3 vs 73.5 +/- 26.1, respectively). The area under the receiver operator characteristic curves for RNFL thickness were similar (P > .05) using FD-OCT (average, 0.88; superior, 0.80; inferior, 0.94) and TD-OCT (average, 0.87; superior, 0.79; inferior, 0.95). Cross-sectional peripapillary RNFL thickness measurements obtained using FD-OCT generated with the RTVue are greater than those obtained with TD-OCT and have similar diagnostic performance for glaucoma detection.

Retinal nerve fiber layer thickness in nonarteritic anterior ischemic optic neuropathy: OCT characterization of the acute and resolving phases

To evaluate longitudinal changes in retinal nerve fiber layer (RNFL) thickness in patients with nonarteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography (OCT). Prospective, observational case series study. Sixteen eyes from 15 consecutive patients affected with NAION were analyzed. The fellow unaffected eyes served as controls. Patients were divided into three different study groups: (1) patients with visual field (VF) defect confined to the inferior hemifield (five eyes), (2) patients with diffuse VF loss (seven eyes), and (3) patients with central or centrocecal scotoma (four eyes). The main outcome was peripapillary RNFL thickness measurement by Stratus-OCT. In group 1, OCT demonstrated RNFL involvement limited to the temporal , superior and nasal optic disc quadrants, both in acute and athophic stages. Diffuse RNFL damage involving all quadrants around the disc was observed in group 2 patients. Group 3, by contrast, revealed RNFL atrophy limited to the superior and temporal sectors of the disc. OCT can identify different patterns of RNFL involvement specific to different classic VF defects in eyes with NAION. Our results corroborate previous histologic findings in optic nerves affected with NAION.

Retinal Nerve Fiber Layer Split Bundles Are True Anatomic Variants

The presence of retinal nerve fiber layer (RNFL) split bundles recently was described in normal eyes scanned using scanning laser polarimetry. In this study, the authors set out to ascertain whether RNFL split bundles can be found in histologic sections of normal human eyes. Histologic study of postmortem human eyes. Fourteen normal postmortem eyes obtained from 13 individuals. Peripapillary RNFL thickness measurements were plotted, for each eye, from ring sections of 3.0, 3.5, 4.0, and 4.5 mm in diameter. The presence of superior or inferior split RNFL patterns, or both, was sought. The presence of superior or inferior split bundles or both in the histologic data. Five of 14 eyes demonstrated a distinct histologic pattern of RNFL split bundles, of which 3 were found superiorly and 2 inferiorly. None of these 14 eyes demonstrated both a definite superior and a definite inferior split. This study provides histologic evidence demonstrating that RNFL split bundles are likely a true anatomic finding, rather than an imaging artifact, and that their presence seems to be relatively common in normal eyes. The presence of a split bundle, being a normal variant, should be distinguished from RNFL loss.

Retinal Sensitivity and Retinal Nerve Fiber Layer Thickness Measured by Optical Coherence Tomography in Glaucoma

To define the relationship between retinal light sensitivity and peripapillary retinal nerve fiber layer (RNFL) thickness as measured using the Stratus optical coherence tomograph (OCT). Prospective study. Institutional. A total of 126 healthy subjects, 42 patients with ocular hypertension (OHT) and 64 patients with primary open-angle glaucoma (POAG) were examined by the 24/II program of the Humphrey Field Analyzer (Carl Zeiss Meditec, Inc, Dublin, California, USA), and the Fast RNFL Thickness examination of the OCT. Individual visual field (VF) test scores and peripapillary RNFL thickness measurements were grouped into six topographically corresponding sectors whose mean values were then calculated. One eye per patient was randomly chosen. The correlations between mean retinal sensitivity (expressed both in decibel and unlogged scales) and RNFL thickness were described with linear and logarithmic regression analyses. With reference to all 232 individuals, the equation that best explained the model was logarithmic when using the decibel scale, and either linear or logarithmic when using the unlogged scale. A statistically significant, age-adjusted correlation between function and structure was found in most sectors both using the decibel (logarithmic regression analysis r(2) 0.24 to 0.61, P < .001), and the unlogged scale (r(2) 0.37 to 0.53, P < .001 in both linear and logarithmic regression analyses). When using the decibel scale, the logarithmic equation may better explain the function/structure relationship between retinal sensitivity and OCT-measured RNFL thickness along a wide spectrum of glaucoma continuum. These results support the need to combine functional and structural tests in the detection of early glaucoma.

Reproducibility of Peripapillary Retinal Nerve Fiber Layer and Macular Retinal Thickness Measurements Using Optical Coherence Tomography

We investigated the interoperator reproducibility of peripapillary retinal nerve fiber layer (RNFL) and macular retinal thickness measurements using optical coherence tomography (OCT) in healthy Taiwanese eyes. In this study, OCT-3 was used by three trained and experienced operators to measure peripapillary RNFL and macular retinal thickness in a randomly chosen single eye from each normal subject. Mean thickness levels and the differences in thickness measurements among the three operators were calculated and compared. The eyes of 39 subjects (24 females and 15 males) were enrolled. The mean age of the subjects was 30.4 +/- 16.1 years (range, 11-46 years). The mean pupil diameter after pupillary dilation was 7.4 +/- 0.6mm (range, 6-9 mm). Comparing peripapillary RNFL and macular retinal thickness measurements after pupillary dilation, there were no significant differences in: superior, inferior, temporal, and nasal peripapillary areas; 6 mm total macular volume and foveal thickness; and 1, 3 and 6 mm perifoveal areas among the three operators. In this study, OCT thickness measurements showed good interoperator reproducibility among three trained and experienced operators.

Scanning Laser Polarimetry With Variable Corneal Compensation and Optical Coherence Tomography in Tilted Disk

To determine whether scanning laser polarimetry with variable corneal compensation (GDx-VCC) or optical coherence tomography (OCT) is helpful for the analysis of the retinal nerve fiber layer (RNFL) thickness in glaucoma subjects with tilted disk. Retrospective case-control study. We included 21 glaucomatous eyes with tilted disk and 35 glaucomatous eyes without tilted disk. Peripapillary RNFL thickness measurement by GDx-VCC and OCT, and also visual field testing with a Humphrey Field Analyzer program 30-2 (HFA) were performed in all subjects. In the group without tilted disk, the RNFL thickness values obtained with GDx-VCC and OCT analysis had a good correlation with mean deviation (MD), and clearly showed stage-dependent reduction. Conversely, in the group with tilted disk, a discrepancy in the RNFL measurement between GDx-VCC and OCT was observed. The correlation of RNFL measurement to the visual field was further examined at each hemifield (superior and inferior). In the group without tilted disk, the measurements of both instruments at each hemifield were in good correlation with the mean pattern deviation values. However, in the group with tilted disk, the GDx-VCC derived values did not correlate with the visual field defect in both hemifields, whereas OCT was in good association with both mean pattern deviation values. Infrared images acquired with a wavelength of nearly 780 nm revealed a high reflex from the sclera in the tilted disk. Our study has suggested that RNFL analysis by OCT is more suitable for the glaucoma assessment in the tilted disk compared with GDx-VCC.

Retinal Nerve Fibre Layer Measurements in Normal Eyes in Zaria Using Optical Coherence Tomography

Purpose: To determine the retinal nerve fiber layer (RNFL) measurements in normal eyes in Zaria and to investigate the effect of age and axial length on RNFL thickness. Materials and Methods Forty eyes of 40 healthy subjects aged between 18 and 73 underwent peripapillary RNFL thickness measurement by a series of three circular scans with a 3.4 mm diameter (Stratus optical coherence tomography, RNFL thickness 3.4 acquisition protocol). The mean RNFL values were correlated with age and axial length. The statistical analysis used was Pearson's coefficient of correlation, linear regression, and paired t-test with the analyse-it® software for Excel. Results: The mean age of the subjects was 35 years, range18.0-73.0 years. Mean RNFL thickness global average was 107.055 μm standard deviation (SD 9.219 μm) with the RNFL in the superior quadrant being the thickest (mean: 139.0 mm SD 15.0 mm), there was no significant correlation with axial length in this study (P = 0.56) but there was a negative correlation between global RNFL average and age (r = ­0.56 P = 0.0002). Conclusion: This study provides normative RNFL values for normal eyes in Zaria locality. It can be used as a reference for the normal measurements of RNFL in this environment. Age demonstrates a significant negative correlation with RNFL thickness.