LAUSR

PURPOSE To compare OCT-measured Bruch's membrane opening-minimum rim width (MRW), peripapillary retinal nerve fiber layer (pRNFL) measurements and MRW:pRNFL ratios in eyes with compressive optic neuropathy (CON), glaucoma and controls, and evaluate the ability of these parameters to differentiate CON from glaucoma. DESIGN Prospective, cross-sectional study. METHODS Setting: single-center tertiary hospital and outpatient clinic. PATIENT POPULATION 115 eyes of 77 subjects, 34 with CON from chiasmal lesions, 21 with glaucoma, and 22 normal controls. OBSERVATION PROCEDURES OCT-measured MRW, pRNFL and MRW:pRNFL ratios for each optic disc sector and global average. MAIN OUTCOME MEASURES MRW, pRNFL and MRW:pRNFL ratios compared using generalized estimated equations. Area under the receiver operating characteristic curve (AUC), positive and negative likelihood ratios were calculated. RESULTS MRW and pRNFL measurements were significantly reduced in CON and glaucoma compared to controls. In glaucoma, MRW was thinner than in CON in the global average, the inferotemporal, superonasal, inferonasal and vertical average measurements, but a significant overlap was observed in many parameters. MRW:pRNFL ratios increased the ability to discriminate between CON and glaucoma, as shown by the high AUCs, high positive likelihood ratios and low negative likelihood ratios, especially in the nasal disc sector and the nasal and temporal average. CONCLUSIONS MRW measurements alone cannot reliably distinguish CON from glaucoma, but the combination of MRW, pRNFL and MRW:pRNFL ratios significantly improves accuracy. When comparing the two conditions, MRW:pRNFL ratios yielded higher AUC, PLR and NLR values, suggesting this parameter may be helpful in clinical practice.