Analysis of Optic Nerve and Macula Microvasculature in Patients with Polycythemia Vera Using Optical Coherence Tomography Angiography

Objective We aimed to investigate the microvascular structure of the macula and optic nerve head in patients with polycythemia vera (PV) by using optical coherence tomography (OCT) and OCT angiography (OCTA). Materials and Methods Thirty patients with no systemic disease other than PV and 27 healthy individuals between the ages of 18 and 60 were included in the study. The patients underwent a detailed ophthalmologic evaluation including best corrected visual acuity (BCVA), intraocular pressure measurement with a non-contact tonometer, anterior segment and fundus examination with a biomicroscope, OCT and OCTA measurements, as well as blood tests. Data from one eye of each study participant was evaluated. Results In the macula, superficial capillary plexus (SCP) vascular density (VD) (%) values ​​were found to be significantly lower in the patient group compared to the control group in the inferior half (p = 0.015), superior (p = 0.042), temporal (p = 0.044) and inferior (p = 0.020) areas of the parafovea and in the inferior area of ​​the perifovea (p = 0.043). Deep capillary plexus (DCP) VD values ​​were lower in the patient group compared to the control group in the whole area (p = 0.001), superior half (p = 0.002), inferior half (p = 0.001), parafovea (p < 0.001), and perifovea (p = 0.008). When radial peripapillary capillary plexus (RPCP) VD values ​​from the optic disc were investigated, significantly lower values ​​were observed in the peripapillary (p = 0.007) and nasal superior (p = 0.004) quadrants in the patient group. Conclusion The significantly lower SCP, DCP and RPCP VD values in the patient group may be related to increased blood viscosity, microcirculatory disorders, and ischemia in PV patients. In particular, the slowdown of retinal and choriocapillary circulation due to hyperviscosity may be considered as the basic mechanism explaining the decrease in VD values.