Diagnostic Ability of Macular Nerve Fiber Layer Thickness Using New Segmentation Software in Glaucoma Suspects

Abstract

Purpose. To assess the capacity of internal retinal layer thickness measurements made at the macula using new spectral-domain optical coherence tomography (OCT) software to distinguish between healthy subjects and those with suspected glaucoma. The diagnostic performance of such measurements also was compared with that of conventional peripapillary retinal nerve fiber layer (RNFL) thickness measurements. Methods. The study included 38 subjects with suspected glaucoma and 38 age-matched healthy subjects. In one randomly selected eye of each participant, thickness measurements at the level of the macula were made of the nerve fiber layer (mRNFL), the ganglion cell layer (GCL), and the ganglion cell complex (GCC; GCL + internal plexiform layer) through automated OCT segmentation. Peripapillary RNFL thickness (pRNFL) also was determined using the conventional scan. Results. As the only variable showing intergroup variation, mRNFL in the glaucoma suspects was significantly thinner in the quadrants inner inferior (P = 0.003), inner temporal (P = 0.010), and outer inferior (P = 0.017). The variable best able to discriminate between the two groups was inner inferior mRNFL thickness, as indicated by an area below the receiver operating characteristic (ROC) curve of 0.742. Conclusions. Macular RNFL thickness measurements showed an improved diagnostic capacity over the other variables examined to distinguish between healthy subjects and glaucoma suspects.