Platelet and Thrombophilia-Related Risk Factors of Retinal Vein Occlusion

Abstract

Retinal vein occlusion (RVO) is a heterogenous disorder in which the formation of a thrombus results in the retinal venous system narrowing and obstructing venous return from the retinal circulation. The pathogenesis of RVO remains uncertain, but it is believed to be multifactorial and to depend on both local and systemic factors, which can be divided into vascular, platelet, and hypercoagulable factors. The vascular factors include dyslipidaemia, high blood pressure, and diabetes mellitus. Regarding the platelet factors, platelet function, mean platelet volume (MPV), platelet distribution width (PDW), and platelet large cell ratio (PLCR) play key roles in the diagnosis of retinal vein occlusion and should be monitored. Nevertheless, the role of a hypercoagulable state in retinal vein occlusion remains unclear and requires further studies. Therefore, the following article will present the risk factors of RVO associated with coagulation disorders, as well as the acquired and genetic risk factors of thrombophilia. According to Virchow’s triad, all factors mentioned above lead to thrombus formation, which causes pathophysiological changes inside venous vessels in the fundus of the eye, which in turn results in the vessel occlusion. Therefore, a diagnosis of retinal vein occlusion should be based on both eye examination and general examination, including laboratory tests.

Multi-color imaging in a unilateral central retinal artery occlusion following dengue fever: A case report and literature review

“…Retinal vascular occlusion can occur due to systemic conditions, such as diabetes, hypertension, hyperlipidemia, autoimmune diseases, atherosclerosis, and cardiac conditions [15][16][17][18]. Hematological conditions predisposing to increased levels or activity of procoagulant factors (prothrombin, factor Va, thrombin, fibrinogen), decreased levels or activity of endogenous anticoagulants (protein C, protein S, antithrombin III), decreased levels or activity of fibrinolytic compounds (plasminogen and plasmin), increased levels or activity of lipoproteins, or genetic mutations in factor V may cause retinal vascular occlusions [15][16][17][18].…”

Platelet-Derived Procoagulant Microvesicles Are Elevated in Patients with Retinal Vein Occlusion (RVO)

“…Importantly, larger platelets are characterized by the production of higher levels of thromboxane A2 and an increased expression of glycoprotein Ib and IIb/IIIa receptors, which is responsible for activation of platelets [ 17 ]. Despite the fact that arterial and venous thrombosis were considered to be separate phenomena for a long time, they are characterized by many common features in their pathophysiology as well as their risk factors [ 18 , 19 ]. Both types of thrombosis share the occurrence of a hypercoagulable state and inflammatory condition, incidence of prothrombotic microvesicles, and excessive platelet activation [ 18 , 19 ].…”

“…Despite the fact that arterial and venous thrombosis were considered to be separate phenomena for a long time, they are characterized by many common features in their pathophysiology as well as their risk factors [ 18 , 19 ]. Both types of thrombosis share the occurrence of a hypercoagulable state and inflammatory condition, incidence of prothrombotic microvesicles, and excessive platelet activation [ 18 , 19 ].…”

Antivascular endothelial growth factor for macular oedema secondary to retinal vein occlusion: a systematic review and meta-analysis

“…Retinal vein occlusion (RVO) is a heterogeneous disease, in which the thrombus is formed the retinal venous system, resulting in the obstruction of venous return from the retinal circulation. 1 The classification of RVO depends on the site of occlusion: branch RVO (BRVO) and central RVO (CRVO). 2 Both CRVO and BRVO can be further classified into non-ischaemic subtype and ischaemic subtype based on the amount of retinal capillary perfusion.…”

“…Retinal vein occlusion (RVO) is a heterogeneous disease, in which the thrombus is formed the retinal venous system, resulting in the obstruction of venous return from the retinal circulation 1. The classification of RVO depends on the site of occlusion: branch RVO (BRVO) and central RVO (CRVO) 2.…”