Orbital Doppler Evaluation of Blood Flow Velocities in Optic Neuritis

Purpose: To evaluate orbital blood flow velocities and optic nerve diameter with Doppler and gray-scale sonography in patients with acute unilateral optic neuritis (ON) Methods: Orbital Doppler and gray-scale sonography was performed in 46 eyes of 23 patients aged 19-47 with acute unilateral ON. ON was diagnosed by an ophthalmologist on the basis of clinical presentation, presence of decreased visual acuity (VA) and assessment of visual evoked potentials (VEP). The peak systolic (PSV) and end-diastolic (EDV) blood flow velocities and resistance and pulsatile indices (RI, PI) of the ophthalmic artery (OA), central retinal and posterior ciliary arteries (CRA, PCAs) and optic nerve diameter were measured in both eyes. We compared results from affected and unaffected eyes using the paired T-test. The area under the receiver-operating characteristic (ROC) curves was used to assess diagnosis of ON on the basis of measured blood flow parameters of the OA, CRA and PCAs and optic nerve diameter. Results: Optic nerve diameter in eyes with ON was significantly higher than that of the control eyes (P<0.001). The mean (SD) optic nerve diameter was 4.1 (0.8) mm in affected eyes and 3.0 (0.4) mm in unaffected eyes (P<0.001). There were no differences in average PSV, EDV, RI and PI of OA and CRA between affected and unaffected eyes (P>0.05). The mean RI in the PCAs (P<0.05) was slightly lower in the eyes with ON than in the contralateral eyes. The area under the ROC curves was 0.928 for optic nerve diameter. Conclusion: Optic nerve diameter was related to ON, but orbital blood flow parameters were not.