Optical Coherence Tomography in Clinically Isolated Syndrome

Abstract

Objective: Optical coherence tomography (OCT) is a non-invasive, accurate and simple high resolution technique to quantify the thickness of retinal nerve fiber layer (RNFL). Measurement obtained with OCT may represent a surrogate biomarker for multiple sclerosis (MS). The aim of the study was to examine retinal nerve fiber layer measured by OCT in patients with clinically isolated syndromes (CIS) and to investigate whether RNFL thickness is useful for determining the prognosis of patients with CIS. Methods: Patients with CIS underwent a complete neurological examination. High field brain MRI(3T), cervical MRI and lumbal puncture were performed within three months of the first attack. They also underwent an ophthalmological evaluation including visual acuity and optical coherence tomography (OCT) within the first week after diagnosis. Results: Twenty-four patients with CIS were recruited, including 8 patients with optic neuritis (ON),6 with spinal cord syndrome, 5 with brainstem symptoms and 5 with sensory and other syndromes. Oligoclonal IgG bands were present in 57% of patients. Seven patients fulfilled at least three out of four Barkhof criteria in MRI. 54.2% of all patients and 56.3% of the patients without ON showed the presence of at least one quadrant of an optic nerve with a decreased RNFL thickness. The presence of at least one quadrant of an optic nerve with a RNFL thickness at a p < 5% cut-off value had a sensitivity of 71% and a specificity of 59% for predicting positive MRI (dissemination in space). Specificity increased to 82% if the cut-off value is set at p < 1%. Conclusion: Patiens with CIS but without ON showed affected RNFL thickness. OCT is an easier, faster and more cost-efficient exploration than MRI. OCT may be useful for predicting conversion in multiple sclerosis and useful as a surrogate biomarker. Follow-up is needed to confirm these preliminary results