Objective: The aim of this study is to assess the ultrastructure and vascular density of the optic disc and macula by optical coherence tomography angiography (OCT-A) in patients with Polycythemia Vera (PV) and to compare with healthy controls.

Material and Method: Twenty-four eyes of 12 PV patients and 34 eyes of 17 healthy subjects with similar age and sex were recruited in this study. AngioVue OCT-A images were taken in an area of 4.5 X 4.5 mm for optic disc and 6X6 mm for macula. Retinal nerve fiber layer (RNFL) thickness, radial peripapillary capillary vessel density, central macular thickness, macular capillary plexus vascular densities, foveal avascular zone, acircularity index were measured.

Results: RNFL thickness in the superior and temporal area were significantly thinner in PV patients than in controls (respectively 126.83± 16.76 & 138.94± 14.02 p =0.004; 69.62± 10.15 &76.94 ±10.15 p =0.009). Peripapillary capillary vessel density in whole image, peripapillary and superior peripapillary region were significantly reduced in PV patients (48.50± 2.80 & 49.86 ± 2.18 p =0.042; 51.85± 2.98 & 53.22± 2.24 p =0.050; 51.69± 2.88 & 53.48± 2.55 p =0.016). Superficial macular vessel density were significantly reduced in whole image, parafoveal and perifoveal regions in PV patients (45.27 ±2.73 & 47.34±3.01 p= 0.014; 45.76± 3.87 &48.16±4.14 p =0.037; 45.84±2.76 & 48.06±3.09 p =0.008). Parafoveal choriocapillary vessel density was significantly increased in PV patients (67.48±3.16 & 65.29±4.23 p =0.034).

Conclusion: RNFL thickness decreases, peripapillary and macular vessel density decreases and choriocapillary vessel density increases in PV patients. This can be related to increased blood viscosity and delayed blood flow.