Concordance of Retinal Nerve Fiber Layer Defects between Fellow Eyes of Glaucoma Patients Measured by Optical Coherence Tomography

PurposeTo determine the pattern of agreement of retinal nerve fiber layer (RNFL) defects between fellow eyes of glaucoma patients measured with optical coherence tomography (OCT).DesignObservational, cross-sectional study.MethodsSeventy-seven glaucoma patients (154 eyes) underwent OCT (Stratus) imaging with the fast RNFL thickness protocol in both eyes. RNFL thickness at each location (12 clock-hour sectors and 4 quadrants) was measured. Main outcome measures were correlations between fellow eyes for RNFL thickness and categorical classifications of RNFL thickness. Nonfellow pairs of eyes, matched randomly, were used as controls.ResultsFellow eyes showed significant correlations of RNFL thickness in all sectors and quadrants. Categorical ranking also showed significant agreement between fellow eyes in sectors 1 (P < .01) and 7 (P < .03), and in the superior quadrant (P < .01), inferior quadrant (P < .04), and total RNFL thickness (P < .04). None of the paired eyes in the control analysis showed significant correlations.ConclusionsThe measurement of RNFL thickness and its categorical classification with OCT identified symmetry between fellow eyes of glaucoma patients. Categorical agreement on defective locations was found mostly for the inferior and superior locations, which corresponds with the typical pattern of early glaucomatous damage. Glaucomatous RNFL damage in 1 eye is correlated with damage at corresponding locations of the fellow eye.