Using ImageJ to Evaluate Optic Disc Pallor in Traumatic Optic Neuropathy

PURPOSE To evaluate optic disc pallor using ImageJ in traumatic optic neuropathy (TON). METHODS This study examined unilateral TON patients. The optic disc was divided into 4 quadrants (temporal, superior, nasal, and inferior), consistent with the quadrants on optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness maps. Optic disc photography was performed and disc pallor was quantified using gray scale photographic images imported into ImageJ software. The correlation between optic disc pallor and RNFL thickness was examined in each quadrant. RESULTS A total of 35 patients (31 male, 4 female) were enrolled in the study. The mean participant age was 34.8 ± 15.0 years (range, 5 to 63 years). Overall RNFL thickness decreased in 6 patients, with thinning most often occurring in the inferior quadrant (28 of 35 eyes). There was a significant correlation between optic disc pallor and RNFL thickness (superior, rho = -0.358, p = 0.04; inferior, rho = -0.345, p = 0.04; nasal, rho = -0.417, p = 0.01; temporal, rho = -0.390, p = 0.02). The highest level of correspondence between disc pallor and RNFL thickness values outside of the normative 95th percentiles was 39.3% and occurred in the inferior quadrant. CONCLUSIONS Optic disc pallor in TON was quantified with ImageJ and was significantly correlated with RNFL thickness abnormalities. Thus, ImageJ evaluations of disc pallor may be useful for evaluating RNFL thinning, as verified by OCT RNFL analyses.