Quantifying axonal loss after optic neuritis with optical coherence tomography

Abstract

The aim of this study was to evaluate any correlation between changes in retinal nerve fiber layer (RNFL) thickness after optic neuritis (ON) and visual outcome. The authors used optical coherence tomography (OCT) to measure RNFL after ON. Fifty-four ON patients underwent repeated evaluations with OCT and standardized ophthalmic testing after. Regression analyses were used to determine the relationship between RNFL thickness and visual function. Thinning of the RNFL was seen in the most of the patients (74%), occurred most often within three to six months of ON. The average RNFL value was thinner (P < .0001) in the affected eye (78 micron) compared with the unaffected eye (100 micron). Patients with incomplete visual recovery demonstrated greater RNFL loss after ON. Regression analyses demonstrated a threshold of RNFL thickness (75 micron), below which RNFL measurements predicted persistent visual dysfunction. The authors conclude that determination of RNFL thickness may predict visual recovery after ON, and that lower RNFL values correlate with impaired visual function. They suggest that OCT may have a potential role as a surrogate marker for axonal integrity within the optic nerve among patients with ON.—Valŕie Biousse