Thesis (M.Sc.) - Cairo University - Faculty of Medicine - Department of Neuro Physiology

Background : Acute Optic neuritis is an inflammatory demyelinating condition that associated with increased diameter of optic nerve sheath which can be measured by trans-orbital sonography. Objectives: To assess the accuracy of measuring optic nerve sheath diameter (ONSD) by ultrasound in acute optic neuritis. Methods: This is a prospective non-randomized case control study carried out on 25 patients and 25 controls. All patients presented with first attack of an acute demyelinating optic neuritis. Both patients and controls were submitted to clinical assessment, pattern and flash visual evoked potential and trans-orbital sonography to measure the optic nerve sheath diameter (ONSD) Results: The ONSD was significantly higher in patients with unilateral ((0.6 ± 0.05 cm) and bilateral (0.6 ± 0.1 cm) optic neuritis compared to controls (0.52 ± 0.06 cm), p value < 0.001 and 0.04 respectively, with a cutoff value 0.57 cm. A significant negative correlation was found between the thickness of the ONSD and the visual acuity r= -0.613, while there was significant positive correlation between visual acuity and amplitude of pattern VEP r =0.702, p value < 0.05 for both. Conclusion: ONSD measurement by orbital sonography is a noninvasive, inexpensive, and easy procedure, which represent a promising new tool to support the clinical diagnosis of acute optic neuritis patients

Issued also as CD