Optic Nerve

The fifth topology in the 2024 McDonald diagnostic criteria¹

Optic neuritis is one of the most common forms of presentation in multiple sclerosis: in 25% of new MS cases optic neuritis is the initial clinical event. Moreover, studies show that 50-70% of all patients with MS will experience optic neuritis at some stage of the condition. Optic neuritis presents with acute unilateral vision loss^{2 - 4}. Visual field defects are present in almost all patients with optic neuritis (97.5%)². Relative afferent pupillary defects (RAPD) occur in 96% of acute unilateral optic neuritis cases⁵, and assessing RAPD is a critical element in the diagnosis and classification of optic neuritis⁶.

 

 

The most frequently observed eye movement disorders in MS are saccadic dysmetria (91%), INO (68%), vestibulo-ocular reflex abnormalities and gaze-evoked nystagmus (36%), fixation instability, and impaired smooth pursuit ^2,7 . Up to 71% of INOs are not detected in routine clinical assessment⁸.

1 Montalban, Xavier et al.  Diagnosis of multiple sclerosis: 2024 revisions of the McDonald criteria. The Lancet Neurology, Volume 24, Issue 10, 850 - 865
2 Frohman EM, Frohman TC, Zee DS, McColl R, Galetta S. The neuro-ophthalmology of multiple sclerosis. Lancet Neurol. 2005;4(2):111-121. 
3 Dhanapalaratnam R, Markoulli M, Krishnan AV. Disorders of vision in multiple sclerosis. Clin Exp Optom. 2022;105(1):3-12.
4 Sheehy CK, Beaudry-Richard A, Bensinger E, Theis J, Green AJ. Methods to Assess Ocular Motor Dysfunction in Multiple Sclerosis. J Neuroophthalmol. 2018;38(4):488-493.
5 Cox TA, Thompson HS, Corbett JJ. Relative afferent pupillary defects in optic neuritis. Am J Ophthalmol. 1981;92(5):685-690. 
6 Petzold A, Fraser CL, Abegg M, et al. Diagnosis and classification of optic neuritis. Lancet Neurol. 2022;21(12):1120-1134.
7 Niestroy A, Rucker JC, Leigh RJ. Neuro-ophthalmologic aspects of multiple sclerosis: Using eye movements as a clinical and experimental tool. Clin Ophthalmol. 2007;1(3):267-272.
8 Frohman TC, Frohman EM, O'Suilleabhain P, et al. Accuracy of clinical detection of INO in MS: corroboration with quantitative infrared oculography. Neurology. 2003;61(6):848-850.