In a study of 56 patients with retinal vein occlusions, Dodson and coworkers (cited in 1) noted statistically significant high levels of beta-thromboglobulin and platelet factor IV. These are platelet-specific proteins stored in alpha-granules that are released into the plasma during platelet aggregation. The increase in platelet proteins may indicate an enhanced platelet activation state in vivo. Increased levels of plasma beta-thromboglobulin along with an enhanced platelet release of proteins are noted in hyperlipidemic patients, in diabetic patients, and also in patients with CRVO who are not diabetic and have a normal lipid profile.

Priluck (cited in 1) reported a case of CRVO associated with increased platelet aggregability in response to epinephrine, collagen, and ADP. This hypercoagulable state slows blood flow and promotes thrombus formation.