Quantitative Analysis of Radial Peripapillary Capillary Network in Patients With Papilledema Compared with Healthy Subjects Using Optical Coherence Tomography Angiography

Background: To quantitatively compare the peripapillary microvascular network between patients with papilledema and healthy subjects using swept source optical coherence tomography angiography. Methods: In this retrospective observational study, patients with papilledema secondary to idiopathic intracranial hypertension and healthy controls were imaged with swept source optical coherence tomography angiography (PLEX Elite 9000; Carl Zeiss Meditec, Dublin, CA) using a 6 x 6 mm scan pattern centered on the optic disc. The capillary perfusion density (CPD) and capillary flux index (CFI) of the radial peripapillary capillaries in the retinal nerve fiber layer (RNFL) were calculated using Zeiss algorithm. Results: Thirty-nine eyes of 20 patients with papilledema and 66 eyes of 33 healthy subjects were imaged. The mean (P < 0.01), superior (P < 0.01), inferior (P < 0.01), and temporal (P = 0.02) CPD significantly differed between both groups. No significant difference was found between both groups for the CFI. The mean (P < 0.01), superior (P < 0.01), inferior (P = 0.01), temporal (P < 0.01), and nasal (P < 0.01) quadrants of the RNFL were positively associated with the CFI. The mean (P < 0.01), superior (P = 0.01), inferior (P = 0.01), temporal (P < 0.01), and nasal (P = 0.01) quadrants of the RNFL were negatively associated with the CPD. Conclusion: Our study showed a decreased peripapillary capillary density without changes in flux intensity in eyes with papilledema. There were a positive association between the CFI and the RNFL and a negative association between the CPD and the RNFL. It confirmed the discriminatory ability of OCTA in differentiating a papilledema secondary to IIH from a normal optic disc, while providing complementary information for understanding papilledema pathophysiology.