Optical coherence tomography in Susac's syndrome.

Susac's syndrome is an autoimmune endotheliopathy with predilection for brain, retina and cochlea (Susac, 1994). Optical coherence tomography (OCT) is a non-invasive method, which is increasingly used in the diagnosis of retinal as well as primary central nervous system diseases. OCT is suggested as a useful diagnostic tool in differentiating Susac's syndrome from multiple sclerosis (MS) (Brandt et al., 2012). This report demonstrates the OCT findings in 3 patients with Susac's syndrome in different stages of the disease. The OCT demonstrated decreased retinal nerve fiber layer (RNFL) thickness, which was patchy in nature and more prominent in the nasal quadrants. We also observed loss of the normal foveal contour, which is uncharacteristic for MS. The extent and degree of the OCT abnormalities in our patients correlated with the stage and severity of the disease and correlated with the findings on the visual field studies. We confirm that OCT is a useful diagnostic tool in Susac's syndrome and helps to differentiate it from MS. Furthermore, OCT may be a non-invasive alternative to fluorescein angiography in longitudinal follow up of these patients.