Acute Optic Neuritis in Multiple Sclerosis: Evaluation of Hemodynamics in the Ophthalmic Artery with Colour Doppler Imaging

Abstract

Background: Optic neuritis (ON) is a common manifestation of multiple sclerosis. It occurs because of the immune-mediated inflammation of the optic nerve. Some vascular factors that could influence the blood flow in the ophthalmic artery (OA) have been suggested in the pathogenesis of ON as well. The purpose of our study was to evaluate blood flow velocities and resistance (RI) and pulsatile (PI) indexes in the OA in patients with acute unilateral ON. Materials and methods: Orbital color Doppler imaging was performed in 27 consecutive patients during acute unilateral ON prior to corticosteroid treatment. ON was diagnosed on the basis of clinical presentation, acute unilateral loss of vision, and assessment of visual evoked potentials (VEP). The peak-systolic velocity (PSV) and the end-diastolic velocity (EDV) and RI and PI were measured in the OA on both sides. We compared results from affected and unaffected orbits, using the paired t-test. We also measured the same parameters in the middle cerebral arteries (MCA) on both sides. Results: The PSV (p < 0.0001), RI (p < 0.0001), and PI (p < 0.0001) in the OA on the side affected by acute ON were significantly higher compared to the unaffected side. There was no difference in EDV in the OA between affected and unaffected sides (p > 0.05). All the parameters in the MCA on both sides were normal. Conclusion: Pathophysiological changes during acute unilateral ON influence the orbital hemodynamics as documented by increased PSV, RI, and PI in the OA on the side affected by ON.

KEYWORDS:

• Color Doppler imaging
• optic neuritis
• orbital hemodynamics