Parapapillary choroidal microvasculature in retrobulbar optic neuritis: An optical coherence tomography angiography...

To compare superficial and deep vascular characteristics of the optic disc in retrobulbar optic neuritis using optical coherence tomography angiography (OCT-A).

Nineteen patients with unilateral non-infectious retrobulbar neuritis were included in the study. The contralateral eyes of each patient were served as controls. OCT-A scans of the optic discs were performed in a 4.5 × 4.5 mm rectangular area, while macular OCT-A scans were performed in a 6 × 6 mm rectangular area. Various parameters, including radial peripapillary capillary (RPC) density, peripapillary retinal nerve fibre layer (pRNFL) thickness, cup volume, rim area, disc area, cup-to-disc (c/d) area ratio, and vertical and horizontal c/d ratios were automatically obtained using the instrument software. The density for superficial capillary plexus (SCP) and deep capillary plexus (DCP) were assessed using macular OCT-A. Parapapillary choroidal microvascular (PPCMv) density was calculated using MATLAB software.

Parafoveal inferior, perifoveal total and inferior SCP densities were significantly decreased in eyes with optic neuritis when compared with contralateral control eyes in OCT-A measurements (respectively, p = 0.027, p = 0.041, p = 0.045). The axial lengths, (p = 0.72), vertical and horizontal cup-disc ratios, and disc area, cup-disc areas, cup volumes, and pRNFL thicknesses between the groups were similar (for each, p>0.05).

This study demonstrated for the first time that patients with retrobulbar optic neuritis had decreased SCP densities, though it did not cause any changes in PPCMv density.