Optical coherence tomography imaging device comparison study in papilloedema secondary to idiopathic intracranial...

Optic nerve imaging assessing papilloedema is an increasingly important clinical measure to guide treatment. The aim of this study was to understand the agreement between two commonly used OCT devices and whether pooling of papilloedema OCT imaging data could be easily facilitated.

People living with idiopathic intracranial hypertension (IIH) underwent non-dilated same-day OCT imaging performed on Spectralis SD-OCT (Heidelberg Engineering, Heidelberg, Germany) and Cirrus 6000 OCT (Carl Zeiss Meditec, Dublin, CA). Comparable measurements were collected (retinal nerve fibre layer (RNFL), maximum height of the optic nerve head and macular ganglion cell layer assessment). Bland-Altman plots were constructed, intraclass correlation coefficient (ICC) and Pearson correlation coefficient were calculated.

Ninety-seven people with a definite diagnosis of IIH were included: 95% were women with a mean age of 31 years. Mean global RNFL thickness was 117.4μm (SD 41.6) on the Spectralis platform and 122.5μm (SD 53.8) on the Cirrus platform. There was excellent agreement between the devices for RNFL thickness measurements (ICC = 0.922), although the Bland-Altman plot revealed increasing discrepancy at higher RNFL thicknesses. Maximum disc height displayed good agreement (ICC = 0.882) between devices. There was a very strong positive correlation between Spectralis GCL volume and Cirrus GC-IPL thickness(r = 0.911).

This OCT imaging dataset spanning a range of papilloedema severity in people with a definite diagnosis of IIH showed good relative agreement of RNFL measurements between Spectralis and Cirrus devices at RNFL thicknesses close to normal, but greater variance with more severe papilloedema. RNFL measurements from the two devices cannot be used interchangeably. Macular GCL assessments showed a strong positive linear correlation.