Change in visual acuity and retinal structures following Repository Corticotropin Injection (RCI) therapy in patients with acute demyelinating optic neuritis: Improvement in low contrast visual acuity in both affected and contralateral eyes in a single-armed open-label study

Abstract

Background: Current treatments after an episode of optic neuritis have limited success protecting the retinal nerves and restoring visual function.

Objective: To assess the effectiveness of Repository Corticotropin Injection (RCI) after the onset of optic neuritis.

Methods: Twenty-four adults were treated with RCI within 2 weeks of symptom onset. Seven exams over 400 days measured low- and high-contrast visual acuity (LCVA and HCVA) and spectral domain optical coherence tomography of the retinal structures. Differences between and among affected and contralateral eyes were assessed using linear mixed models.

Results: HCVA improved in the affected eye over the study (36.2 letters to 52.5), and LCVA improved in both the affected eye (1.8 letters to 6.8) and the contralateral eye (8.3 letters to 11.7). These functional improvements occurred concurrent to a thinning in the papillomacular bundle and the ganglion cell, inner plexiform, and retinal nerve fiber layers, while the inner nuclear, outer plexiform, outer nuclear, and photoreceptor layers thickened.

Conclusion: The eyes affected by the ON and treated with RCI improved in both LCVA and HCVA, and unexpectedly LCVA improved in the contralateral eye as well. This functional improvement was mirrored by structural changes in the retina. This study lays the groundwork for future studies to explore potential neuro-protective and neuro-restorative effects of RCI.

Keywords: ACTH; Low contrast visual acuity; Multiple sclerosis; Optic neuritis; Repository Corticotropin Injection (RCI); Spectral domain optical coherence tomography.