Retinal vein occlusion is the second most common retinal vascular disease after diabetic retinopathy.¹

In central retinal vein occlusion (CRVO), the occlusion is at or proximal to the lamina cribosa of the optic nerve. CRVO is divided into two categories which affect treatment and prognosis: nonischemic and ischemic.²

CRVOs are most commonly associated with advanced age and hypertension, but other risk factors include glaucoma, diabetes, hyperlipidemia, and various hypercoagulable conditions.²

Acute CRVO is a clinical diagnosis manifesting intraretinal hemorrhages in all quadrants, dilated tortuous retinal vasculature, cotton wool spots, optic disc edema, and macular edema.²

In nonischemic CRVOs, visual acuity (VA) is typically better than 20/200 with no relative afferent pupillary defect (RAPD) and an overall good prognosis for visual recovery. In ischemic CRVOs, VA is typically worse than 20/200 with an RAPD, a high chance of anterior segment neovascularization, and an overall poor prognosis for visual recovery.³

In chronic CRVO, small vessels that normally connect the retinal and choroidal circulation near the optic nerve head expand and develop into optociliary shunt vessels which redirect venous drainage from the occluded central retinal vein to the choroid, vortex veins, and ophthalmic veins.³

One key role for optical coherence tomography (OCT) in this diagnosis is identification of macular edema. This may include intraretinal and/or subretinal edema, characterized on OCT as hyporeflective cystoid spaces within the retina (Figure 8.1, white asterisks) or subretinal (Figure 8.1, yellow asterisks), respectively.⁴

There may be hyperreflective foci (HF; Figure 8.1, green arrows) in any layer of the retina and even within the vitreous. HF are thought to be extravasated lipoproteins, and they may serve as a negative prognostic biomarker for final visual acuity.⁵

In acute disease, there may be inner retinal hyperreflectivity, which may represent ischemic damage or retinal disruption.⁶

There may be microaneurysms, hard exudates, cotton wool spots, or neovascularization.

There may be disorganization of the retinal inner layers (DRILs), ellipsoid zone (EZ) and external limiting membrane (ELM) disruption, reduced cone outer segment tip (COST) visibility, and epiretinal membrane.⁴