The Features of Vessel Densities and Hemorheological Parameters in Patients With Central Retinal Vein Occlusion: A Prospective Randomized Case-Control Study.

Background: This study analyzed changes in the vessel densities (VDs) and hemorheological parameters of patients with central retinal vein occlusion (CRVO). Methods: A prospective randomized case-control study was conducted, which included 80 CRVO patients (the study group) and 80 participants with normal fundus (the normal control group). Best-corrected visual acuity (BCVA), optic disc and macular VD, and other structural parameters (C/D ratio, RNFL thickness, etc.) were measured with optical coherence tomography angiography. Hemorheological parameters, including whole blood viscosity at low shear rate (LSR-WBV; 5/s) and high shear rate (HSR-WBV; 200/s), and erythrocyte aggregation index (AI), were also measured. Results: LSR-WBV, HSR-WBV, and AI were significantly higher in CRVO patients (9.009 ± 1.595 mPa·s, 4.981 ± 0.617 mPa·s, and 3.405 ± 1.679) than in participants with normal fundus (8.409 ± 1.110 mPa·s, 4.523 ± 0.597 mPa·s, and 2.880 ± 1.517) (all p < 0.05). CRVO eyes had significantly lower visual acuity, smaller C/D and cup volume, thicker peripapillary RNFL, and lower optic disc and macular VD than unaffected eyes and normal eyes (all p < 0.05). VD inside the optic disc and deep capillary plexus in unaffected eyes was markedly decreased when compared with that in normal eyes (all p < 0.05). BCVA in CRVO eyes was particularly correlated with VD inside disc (p=0.001 and r = -0.391). Conclusion: CRVO patients presented with more serious thrombophilia and higher hemorheological parameters, and the blood perfusion was significantly decreased in the optic disc and macula of CRVO eyes and was partially reduced in unaffected eyes. Moreover, optic disc blood perfusion exerted greater impacts on visual acuity, and inside-disc VD might be the greatest risk factor.