Optical coherence tomography in clinically isolated syndrome: no evidence of subclinical retinal axonal loss.

BACKGROUND Optical coherence tomography has emerged as a new tool for quantifying axonal loss in multiple sclerosis (MS). A reduction in retinal nerve fiber layer (RNFL) thickness is correlated with Expanded Disability Status Scale score and brain atrophy. OBJECTIVE To investigate RNFL and macular volume measurements using optical coherence tomography in the clinically isolated syndrome population. DESIGN Prospective case series. Settings Neurologic clinics at the university hospitals of Lille and Strasbourg (France). PARTICIPANTS Fifty-six consecutive patients with clinically isolated syndrome (18 with optic neuritis and 38 without optic neuritis) and 32 control subjects. MAIN OUTCOME MEASURES Macular volume and RNFL thickness. RESULTS Mean (SD) overall RNFL thickness (98.98 [10.26] microm) and macular volume (6.86 [0.32] microm(3)) in the clinically isolated syndrome population were not significantly different compared with the controls (98.71 [9.08] mum and 6.92 [0.38] microm(3), respectively). No link was noted between atrophy of the RNFL or macula and conversion to MS at 6 months. CONCLUSIONS Optical coherence tomography does not reveal retinal axonal loss at the earliest clinical stage of MS and does not predict conversion to MS at 6 months.