Optical coherence tomography versus automated perimetry for follow-up of optic neuritis

To evaluate the usefulness of optical coherence tomography (OCT) for follow-up of optic neuritis (ON) compared with subjective visual function tests.

Twelve patients with ON underwent a complete ophthalmological evaluation at initial diagnosis, including best corrected visual acuity (VA), visual fields testing and OCT examination. These examinations were repeated periodically over 6 months. Retinal nerve fibre layer (RNFL) thickness evolution was analysed and correlated with VA and visual field mean deviation.

Six months after ON, mean RNFL in the affected eye decreased significantly compared with that in the fellow eye (24.54%). A significant correlation was found between RNFL thinning and final VA (r = 0.807, p = 0.005), with a 1-line drop in VA for every 5.4-micro m decrease. All patients with an altered visual field had an abnormal RNFL value; of the seven patients with normal visual fields, 57% had an abnormal RNFL value (p < 5%).

Optical coherence tomography can detect axonal damage as early as the third month after an isolated initial episode of ON, even in the presence of normal visual fields. Mean RNFL thinning is correlated with final VA.