Transorbital ultrasonography for measuring optic nerve atrophy in multiple sclerosis

Abstract

we aimed to evaluate the utility of transorbital ultrasonography (TOS) in optic nerve assessment and quantification of ON atrophy in MS patients, and to determine whether ON atrophy correlates with the disease duration and disability measured on the Kurtzke Expanded Disability Status Scale (EDSS). Prospective, multicentre, blinded cohort study of 59 patients diagnosed with relapsing-remitting MS and 36 controls. When measured with TOS, the diameter of both the right (2.69±0.30mm in cases; 3.20±0.19mm in controls, P<.0001) and left (2.71±0.26mm in cases; 3.24±0.15mm controls, P<.0001) ON of study patients was smaller than controls. We observed a negative correlation between EDSS and both right (ρ=.524) and left (ρ=.469) ON diameter. We also observed a negative correlation between disease duration and both right (r=.602) and left (r=.538) ON diameter. No difference was observed in the diameter of both ON among patients with a history of optic neuritis (right OND 2.68±0.29mm; left OND 2.69±0.25mm) and patients with no history of optic neuritis (right OND 2.70±0.30mm; left OND 2.73±0.27mm) (P=.805; P=.651). The thickness of ON measured with TOS is correlated with EDSS and the duration of the disease without being interfered by the previous history of optic neuritis. TOS could be a reliable technique for measuring ON atrophy in MS.