Diagnostic Validity of Optic Disc and Retinal Nerve Fiber Layer Evaluations in Detecting Structural Changes after Optic Neuritis

Purpose: To assess the diagnostic validity of morphometric examination of the optic disc and retinal nerve fiber layer (RNFL) thickness to detect permanent structural changes after retrobulbar optic neuritis (ON). Design: Evaluation of a diagnostic test. Participants: Twenty-five patients with a history of retrobulbar ON and 29 disease-free controls. Methods: The optic discs were evaluated by means of confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph [HRT III]), and RNFL thickness by means of scanning laser polarimetry (GDx), and optical coherence tomography (OCT). Vision function was assessed in all subjects by testing visual acuity, contrast sensitivity, color vision, visual field (VF), and visual evoked potentials (VEPs). Statistical comparisons were made between the affected (ON) and unaffected eyes (non-ON) of the patients with ON, and between these eyes and control eyes (Mann-Whitney test and Wilcoxon's test). Receiver operating characteristic (ROC) curves, and sensitivity and specificity in discriminating ON from control eyes, were calculated for the significant parameters. Correlations between the tests were calculated by means of Spearman's correlation coefficient. Main Outcome Measures: We compared OCT, GDx, HRT, and visual testing results in ON eyes versus control eyes. Results: All of the visual function test parameters and RNFL thickness (GDx and OCT) were significantly different between the ON eyes and both the non-ON and control eyes (P