Swept-source OCT angiography imaging of the macular capillary network in glaucoma

To evaluate the macular capillary network density of superficial and deep retinal layers (SRL/DRL) by swept-source optical coherence tomography angiography (OCTA) in patients with primary open angle glaucoma (POAG) and to compare the results with those of normal subjects.

In this prospective study, 24 eyes of 24 normal individuals and 24 eyes of 24 patients with mild to moderate POAG underwent fovea centred 6×6 mm cube macular OCTA imaging by a swept-source OCTA device (Triton, Topcon, Tokyo, Japan). Quantitative analysis of the retinal vasculature was performed by assessing vessel density (VD) as the ratio of the retinal area occupied by vessels at the SRL and DRL.

The mean VD (ratio) at the SRL and DRL was statistically significantly lower in patients with POAG (SRL, p<0.001; DRL, p<0.001). In the SRL, the mean±SD VD ratio was 0.34±0.05 in patients with POAG and 0.40±0.02 in normal individuals (p<0.001). In the DRL, the mean (SD) ratio was 0.37±0.05 in patients with POAG and 0.43±0.02 in normal individuals (p<0.001). The mean VD at the SRL was significantly correlated with ganglion cell inner plexiform layer thickness (r=0.42, p=0.04) but not with visual field mean deviation (r=0.4, p=0.06) and retinal nerve fibre layer thickness (r=0.5, p=0.06). The mean VD at the DRL did not show significant correlation with any other glaucoma parameter (p>0.05).

The assessment of macular VD by swept-source OCTA may offer additional information for detection of glaucoma.