Cluster 283: rvo retinal csr hypercoagulability glaucoma hyperviscosity hypertension ocular history occlusion 
Cluster 621: portal vein main thrombosis invasion mesenteric smv superior encasement occlusion 
Cluster 817: rvo retinal occlusion vein history current evidence risk factors patients 
Cluster 1668: retinopathy retinal serous occlusion vein rvo csr central history current 
Cluster 2172: retinal detachment macular degeneration degenerative history vein ophthalmologic occlusion neurosensory