Combining Nerve Fiber Layer Parameters to Optimize Glaucoma Diagnosis with Optical Coherence Tomography

Abstract

Purpose-To identify the best combination of Stratus optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness parameters for the detection of glaucoma. Design-Observational cross-sectional study.Participants-Eighty-nine age-matched normal and perimetric glaucoma participants enrolled in the Advanced Imaging for Glaucoma Study.Methods-The Zeiss Stratus OCT system was used to obtain the circumpapillary RNFL thickness in both eyes of each participant. Right and left eye clock-hour data are analyzed together, assuming mirror-image symmetry. The RNFL diagnostic parameters were combined using either or-logic or and-logic approaches.Main Outcome Measures-Area under the receiver operating characteristic curve (AROC), sensitivity, and specificity are used to evaluate diagnostic performance.Results-Overall average RNFL thickness has the highest AROC value (0.89) of all single parameters evaluated, followed by the inferior and superior quadrants (0.88 and 0.86, respectively). The clock hours with the best AROC values are in the inferior and superior quadrants. The highest AROC (0.92) was achieved by the or-logic combination of overall, inferior, and superior quadrant RNFL thicknesses. The 3-parameter combination was significantly better than the overall average alone (P = 0.01) The addition of more quadrants or clock hours to the combination reduced diagnostic performance.Conclusions-The best stand-alone diagnostic strategy for Stratus OCT RNFL data is to classify an eye as glaucomatous if the overall, inferior quadrant, or superior quadrant RNFL thickness average is below normal.Glaucoma is an optic neuropathy characterized by irreversible loss of neural tissue and visual field (VF). Currently, definitive glaucoma diagnosis is based on VF testing. However, between 30% and 50% of the ganglion cells may be lost before abnormalities appear in perimetric Optical coherence tomography, first described by Huang et al, 4 is the only imaging modality with sufficiently fine depth resolution to measure the RNFL thickness directly. Measurements of the circumpapillary RNFL are reproducible 7-9 and useful in the early diagnosis of glaucoma. [10][11][12][13][14][15][16][17][18][19] Stratus (Carl Zeiss Meditec, Inc., Dublin, CA) is the most widely used OCT system for glaucoma diagnosis. Stratus measures the RNFL thickness profile along a 3.4-mm-diameter circle around the optic disc. Based on the profile, the averages of overall, quadrant, and clockhour RNFL thickness are computed and displayed. At present, the clinician has no clear guideline on whether one, several, or all of these diagnostic parameters should be used in the clinical diagnosis of glaucoma. Based on the area under the receiver operating characteristic curve (AROC), some studies have shown the overall RNFL thickness average to be the best diagnostic parameter. 11,13,14,16,19 Other studies have shown the inferior 10,17,20 or superior 21 quadrant RNFL thickness average to be the best, in agreement with clinical observation that glaucomatous optic...

Retinal Nerve Fiber Layer Thickness in Normals Measured by Spectral Domain OCT

“…8 Table 4 shows a summary of publications on RNFL thickness evaluation in normal patients using the OCT. [9][10][11][12][13][14][15][16][17][18][19] The table is restricted to studies using 3.4-mm diameter OCT circle scans and to study populations containing predominantly white patients to be able to compare the results with ours (adjusted to mean age, age range, and range of refractive error if information available in the respective publication). The RNFL thickness measured with SOCT in our study was very close to the reported RNFL thicknesses measured with Stratus OCT in most reports, especially in the more recent ones.…”

Keratoconus Diagnosis Using Anterior Segment Polarization-Sensitive Optical Coherence Tomography

“…The AUROC values were computed as in previous studies. 9,33,34 The AUROCs of Mahalanobis distances were also calculated. In addition, for each evaluated parameter, sensitivity and specificity were assessed according to the formula mean þ 2.33 standard deviations for the normal group, and the first percentile value FIGURE 2.…”

Effect of pupil dilation on retinal nerve fibre layer thickness measurements and their repeatability with Cirrus HD-OCT

“…Optical coherence tomography (OCT), first described in 1991 by Huang et al, 1 has a major role in this context and has been applied in the diagnosis of several diseases of the optic nerve, such as glaucoma, optic neuritis, papilledema, hereditary optic neuropathies, and multiple sclerosis. [2][3][4][5][6] Until recently most clinical investigations were carried out by using time-domain OCT (TD-OCT), which has been available since the mid 90s on the OCT 1 and since 2002 on the Stratus OCT (both from Carl Zeiss Meditec, Dublin, CA, USA). TD-OCT uses a scanning interferometer and an 820-nm infrared light source that is split into two separate beams: one beam scans a tissue being analysed, and the other one functions as a reference beam that is reflected by a moving reference mirror.…”