NONINVASIVE EVALUATION OF CHORIORETINAL AND PERIPAPILLARY MICROVASCULAR ALTERATIONS IN ESSENTIAL THROMBOCYTHEMIA

To evaluate the retinal, peripapillary, and choroidal microvascular structures in patients with essential thrombocythemia (ET), a myeloproliferative neoplasm characterized by sustained thrombocytosis and an increased risk of thrombotic events, using optical coherence tomography angiography (OCTA).

This prospective, cross-sectional study included 20 ET patients and 20 age- and sex-matched healthy controls. All participants underwent spectral-domain OCTA to assess vessel density (VD) in the superficial and deep retinal capillary plexuses (SCP and DCP), radial peripapillary capillary (RPC) network, and choriocapillaris (CC). Structural parameters, including central macular thickness (CMT), macular ganglion cell complex (mGCC), retinal nerve fiber layer (RNFL), and foveal avascular zone (FAZ), were also evaluated. Statistical analyses included independent samples t-tests or Mann-Whitney U tests based on data distribution.

Patients with ET exhibited significantly increased CMT compared with controls ( P = 0.019), whereas RNFL and mGCC thicknesses showed no significant differences. Peripapillary whole image VD and RPC VD in the nasal-inferior quadrant were significantly reduced in the ET group ( P = 0.042 and P = 0.039, respectively). Most notably, DCP VD was significantly decreased in both parafoveal ( P = 0.004) and perifoveal ( P = 0.010) regions across all quadrants. No significant differences were observed in SCP VD, FAZ metrics, or CC flow parameters ( P > 0.05 for all).

Patients with ET demonstrate subclinical retinal microvascular alterations predominantly affecting the DCP and peripapillary circulation, whereas superficial retinal and choroidal vasculature remains relatively preserved. OCTA may serve as a sensitive, noninvasive tool for detecting early retinal involvement in ET.