Application of Optical Coherence Tomography Angiography in True and Pseudo Optic Disc Swelling

We assessed the optic disc microvasculature in healthy subjects and patients with optic nerve head drusen (ONHD), active papilledema, and acute non-arteritic anterior ischemic optic neuropathy (NAION) using optical coherence tomography angiography (OCTA). Sixteen eyes with ONHD, 31 eyes with active papilledema, 16 eyes with acute NAION, and 32 healthy eyes were included in this prospective and comparative case series. Peripapillary retinal nerve fiber layer (RNFL) thickness and optic disc vasculature maps were recorded by OCTA. Average RNFL thicknesses were greater in the eyes with ONHD, papilledema, and NAION than in control eyes (all Ps < 0.001), but this parameter did not differ among patient groups. In comparison to healthy eyes, the peripapillary vessel density in the ONHD group was not lower ( P = 1.000), in contrast to the papilledema and NAION groups ( P = 0.008, and P < 0.001, respectively). The only difference between eyes with papilledema and ONHD was lower peripapillary vessel density in the papilledema group ( P = 0.018). All vessel density values were lower in the eyes with NAION in comparison to the ONHD (all P s ≤ 0.002). In addition, in the eyes with NAION, the inside disc vessel density was lower than papilledema ( P < 0.001). Peripapillary vascular density is affected during the course of ONHD, papilledema, and NAION. Despite the observed decrease in the vessel density values in true disc edema, further studies are needed to evaluate the application of OCTA for differentiating true from pseudo optic disc edema.