Transorbital Sonography and Visual Outcome for the Diagnosis and Monitoring of Optic Neuritis.

Abstract

Transorbital sonography (TOS) is a promising tool to support the clinical diagnosis of optic neuritis (ON) by showing thickening of optic nerve. In this study, we aimed to define its specific role in follow-up of ON patients. We measured ultrasonography parameters and visual acuity (VA) at presentation and after 1 year in 45 patients with newly diagnosed ON. Two vascular sonographers used B-mode TOS to evaluate mean optic nerve diameter (OND) and optic nerve sheath diameter (ONSD). Median ONSD values were significantly thicker in patients with ON in the affected eye (6.4 mm, interquartile range [IQR]: 6.0-6.9) at presentation compared with the nonaffected side (5.7 mm; IQR: 5.2-6.1) (P < .001). The median OND was not significantly thicker at presentation in the affected eye (3.0 mm; IQR: 2.9-3.4) compared with the fellow eye (2.9 mm; IQR: 2.8-3.2) (P = .09). Logarithmic VA was significantly compromised at presentation in the affected eye (.16; IQR: .00-.55) compared with fellow eye (.00; IQR: .00-.00) (P < .001). After 1 year, no significant difference (P ≥ .05) was found between ONSD or OND of the affected side compared with the nonaffected side. VA improved in most of the patients but remained significantly impaired in affected eye after 1 year. TOS is a useful tool to support diagnosis of ON. This technique seems to have less value to evaluate atrophy of the optic nerve after 12 months.