Usefulness of Automated Measurements of Localized Retinal Nerve Fiber Layer Defects Area Using Significance Map

ABSTRACT

PURPOSE: To evaluate the usefulness of automated measurements of the localized retinal nerve fiber layer (RNFL) defects area in patients with glaucoma. METHODS: Fifty one patients with localized RNFL defects in RNFL red-free photographs and 53 healthy subjects were included. All participants were imaged with 3D spectral-domain optical coherence tomography (OCT). The area of defects was measured with the RNFL significance map (red = p < 1% and yellow = p < 5%) using Image J manually and Matlab software automatically. The area under the receiver operating characteristic curve (AUC) was calculated for the RNFL defect area of the RNFL photograph and RNFL maps, circumpapillary RNFL thickness, optic disc parameter, and macular inner retina thickness. RESULTS: High correlation was observed between manually and automatically measured defect areas in the significance map (red area r = 0.904, red and yellow area r = 0.890). The AUC for manually and automatically measured defects area (0.987, 0.966; p < 5%, p = 0.31, respectively) in the significance map was comparable. The latter demonstrated slightly higher but insignificant difference in AUC for inferior quadrant circumpapillary RNFL thickness (0.936; p = 0.22) and was significantly higher than the inferior ganglion cell layer plus inner plexiform layer thickness (0.894) and vertical cup to disc ratio (0.869) (p = 0.018, p = 0.008, respectively). CONCLUSIONS: The automated measurements of the RNFL defect area in the significance map performed adequately in detecting localized RNFL defects and had a better performance than macular inner retina and optic nerve parameters.