Abstract
Purpose: :
To assess the ability of Optical Coherence Tomography (OCT), Scanning Laser Polarimetry (GDx VCC) and Confocal Scanning Laser Ophthalmoscopy (HRT III) in detecting RNFL and/or optic disc damage in patients with history of acute retrobulbar optic neuritis and a complete recovery of visual acuity.
Methods: :
Twenty five patients (mean age 37 years) with a previous episode of unilateral optic neuritis and 29 control subjects (mean age 35) underwent a throughout ophthalmological work up including visual acuity, contrast sensitivity, colour vision, SAP, electrophysiological examinations, and morphometric analysis of optic disc and RNFL. The affected eyes were compared with the unaffected fellow eyes and with control eyes from age matched healthy volunteers. First, we evaluated correlation between clinical tests (visual acuity, contrast sensitivity and colour vision), standard automated perimetry (SAP), visual evoked potentials (VEP) and RNFL thickness as measured by OCT, GDx and HRT. Then we assessed the sensitivity, specificity and area under the curve (AUROC) of the best performing OCT, GDx and HRT parameters. Statistical significance was set at p<0.01.
Results: :
A highly significant thinning of RNFL in affected eyes when compared with control eyes (p<0,001) and fellow eyes (p<0,001) was observed with both OCT and GDx. No significant difference in optic disc parameters among groups was found with HRT. Significant correlations (p<0.01) were found between RNFL thickness measured with OCT and GDx and colour vision and visual field. No significant correlation was found with visual evoked potentials (P100 latency). The AUROC for RNFL thickness was 0,905 with OCT and 0,885 with GDx. OCT and GDx showed good sensitivity (72-80%) at a 95% specificity in detecting patients with previous optic neuritis.
Conclusions: :
OCT and GDx VCC can detect axonal loss in optic neuritis. This could be useful for therapeutic decisions as cases with severe axonal damage may need a long-life therapy, and cases with absent or poor axonal damage may only deserve to be followed up without therapy.
Keywords: neuro-ophthalmology: optic nerve • nerve fiber layer • imaging/image analysis: clinical