Reproducibility of Measurements With the Nerve Fiber Analyzer (NFA/GDx)

Colen, Thomas P; Tjon-Fo-Sang, Martha J.; Mulder, Paul; Lemij, Hans G

doi:10.1097/00061198-200010000-00004

Cited by 51 publications

(36 citation statements)

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“…Maximum modulation, ellipse modulation, and the inferior ratio had the highest diagnostic power in this study, and since the two modulation parameters were designed to capture the difference between the thickest and thinnest areas of the RNFL, 6 they may capture features of the RNFL that reflect relatively early loss of RNFL in AACG. The inferior ratio parameter results in this study may indicate that the RNFL was more susceptible to loss in the inferior regions than in the superior region in AACG, although no significant difference was found for the thickness parameter of the inferior average.…”

Section: Discussionmentioning

confidence: 99%

“…The definitions of these parameters have been described elsewhere. 6,7 Statistical analyses were performed using JMP software (SAS Institute, Cary, NC, USA). Mann-Whitney tests with Bonferroni correction were used to evaluate differences between both study groups for the 12 standard GDx parameters, the RNFL thickness from the nasal and temporal averages, BCVA, refraction (spherical equivalent), visual field indices including mean defect (MD), and CPSD.…”

Section: Methodsmentioning

confidence: 99%

“…Good sensitivity and specificity for separating normal from glaucomatous eyes, and high reproducibility have been demonstrated for the instrument. 5,6 The quantification of RNFL thickness using the GDx in normal subjects, patients with ocular hypertension (OH) and primary open-angle glaucoma (POAG), has been described in various studies. [7][8][9] Primary angle-closure glaucoma (PACG) is the most frequent form of glaucoma in Mongolian-type Asian populations.…”

Section: Introductionmentioning

confidence: 99%

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Scanning laser polarimetry in patients with acute angle-closure glaucoma

Tsai

2004

Eye

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Scanning laser polarimetry in patients with acute angle-closure glaucoma

Tsai

2004

Eye

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“…variability in structural measurements, 13,15 inadvertently including a non-normal eye, if anything, would have increased the variability found in this study.…”

Section: Discussionmentioning

confidence: 77%

“…In contrast, comprehensive intradevice reproducibility data exist for the different imaging devices. 11,[13][14][15][16][17][18] Subject C did not undergo a full eye examination and visual field, and is hence only presumed to be normal. As glaucomatous eyes have previously demonstrated higher showing the between-device distribution of measurements for each subject.…”

Section: Discussionmentioning

confidence: 99%

Inter-device reproducibility of the scanning laser polarimeter with variable cornea compensation

Blumenthal

Frenkel²

2004

Eye

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Objective To evaluate the interdevice reproducibility of retinal nerve fibre layer (RNFL) thickness measurements obtained with the commercially available GDx-VCC, a scanning laser polarimeter with variable (individualized) corneal compensation. Methods A prospective instrument validation study in which 13 GDx-VCC devices were tested. One eye each, from three normal subjects were used to test each of the devices, on the same day, by an experienced operator. Variability and reproducibility for each of five GDx parameters were calculated.Results For each of five tested GDx parameters, the coefficient of variation and 95% confidence interval range (lm), for the 13 devices, respectively, were: TSNIT avg: 5.1%, 3.84 lm; Superior avg: 5.3%, 4.82 lm; Inferior avg: 6.1%, 5.50 lm; TSNIT standard deviation: 8.6%, 2.92 lm; and nerve fibre indicator (NFI): N/A, 5.69. Item reliability (Cronbach's alpha) for the five GDx parameters are: TSNIT-Avg: 0.97, Sup-Avg: 1.00, Inf-Avg: 0.84, TSNIT-SD: 0.99, NFI: 0.99. Conclusions With the commercially available GDx-VCC, our results indicate that RNFL measurements appear reproducible across devices.

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Scanning Laser Polarimetry and Detection of Progression After Optic Disc Hemorrhage in Patients With Glaucoma

et al. 2003

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Objective: To examine retinal nerve fiber layer changes with scanning laser polarimetry (SLP) in the eyes of patients with glaucoma and optic disc hemorrhage.Methods: Automated perimetry and SLP were performed in 17 eyes of 17 patients identified prospectively with optic disc hemorrhage. Criteria for visual field progression were based on decreased sensitivity seen at 3 adjacent points on the total deviation plot. Progression on SLP images was defined as a 15% or more decrease in the average thickness of the affected quadrant (superior or inferior), a 25% or more reduction in the affected quadrant ratio, an increase in the nerve fiber analyzer number of 10 or more (GDx Nerve Fiber Analyzer; Laser Diagnostic Technologies), or any change on Serial Analysis of the SLP images. Main Outcome Measures: Visual field progression and SLP image progression.Results: The mean follow-up was 31 months (minimum, 12 months). Of the 17 eyes, 10 (59%) had visual field progression. No significant change was seen on SLP images for either the total group or the group with visual field progression. Five eyes (29%) showed progression on SLP images, 3 of which also showed visual field progression. Ten eyes showed progression on SLP images that was not confirmed on subsequent imaging. Conclusions:In eyes with visual field progression after optic disc hemorrhage, a significant change in the SLP image was not seen. Fluctuation of SLP results in patients with glaucoma necessitates confirmation of progression seen on SLP images.

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Reproducibility of Measurements With the Nerve Fiber Analyzer (NFA/GDx)

Cited by 51 publications

References 0 publications

Scanning laser polarimetry in patients with acute angle-closure glaucoma

Scanning laser polarimetry in patients with acute angle-closure glaucoma

Inter-device reproducibility of the scanning laser polarimeter with variable cornea compensation

Scanning Laser Polarimetry and Detection of Progression After Optic Disc Hemorrhage in Patients With Glaucoma

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