Abstract
Purpose: :
To evaluate the thickness of inner retinal layers in the macula using frequency domain optical coherence tomography (fdOCT) in patients with demyelinating diseases with a view towards detection and differential diagnosis.
Methods: :
A total of 45 normal controls and a cross-section of 135 patients were evaluated. Subjects were divided in 5 different groups: controls (C, n=84 eyes), neuromyelitis optica (NMO, n=50 eyes), longitudinally extensive transverse myelitis (LETM, n=56 eyes), multiple sclerosis (MS) with optic neuritis (MS-ON, n=43 eyes), and MS without ON (MS-nON, n=74 eyes). The individual layers from macular fdOCT (3DOCT-1000; Topcon, Inc) cube scans (128 Bscans) were segmented using a previously validated automated algorithm, [1] which was then manually hand-corrected [2]. For each scan, we determined the thickness of the retinal nerve fiber layer (RNFL), the combined retinal ganglion cell and inner plexiform layers (RGCL+), and the inner nuclear layer (INL). Generalized estimation equation models, accounting for age and inter-eye correlations, were used to determine statistical significance.
Results: :
The RNFL was significantly thinner than controls for all patient groups (p≤0.01 for all groups). Macular RGCL thickness was significantly thinner than controls for the NMO, MSON and MSnON (p<0.001 for the 3 groups). The INL thickness was significantly thicker than controls for the NMO (p=0.003) and LETM (p=0.006) patients but not for MSON or MSnON. Notably, while the RNFL and RGCL were not significantly different between the NMO and MSON groups, the NMO patients had a significantly thicker INL than the MSON(p=0.02) patients.
Conclusions: :
The RNFL was thinner than controls in every patient group, particularly interesting was the statistically significant thinning of the LETM patients (p = 0.001), though the RGCL+ in these patients was not significantly different from controls. Further, the difference in INL thickness between the NMO patients and MS with ON patients may hold promise for differentiating these groups based on fdOCT scans.1. Yang Q et al (2010), Opt. Exp; 2. Raza et al (2011) Archives.
Clinical Trial: :
http://www.clinicaltrials.gov NCT01024985
Keywords: neuro-ophthalmology: diagnosis • ganglion cells • imaging/image analysis: clinical