The leading cause of a central retinal vein or a branch retinal vein occlusion is hypertension (branch > central). Other causes include hypercoaguable states, thrombi, and atherosclerotic events. 20% associated with primary open angle glaucoma (POAG). Retinal vein occlusion is the second most common significant retinal vascular disease behind only diabetic retinopathy.

Occlusion of vein leads to hemorrhaging from the capillaries, not the vein itself.

• Majority of patients over 50 years old. Over 50% have associated vascular disease or diabetes.
• Presenting symptom is a sudden, painless loss of vision.
• Two types:
  
  
  1. Ischemic
  • Ischemic CRVO much more severe.
  • VA markedly reduced, usually 20/200 or worse. CF and HM vision common. Positive APD.
  • Massive hemorrhaging in all four quadrants.
  • Severe macular edema, may get disc edema.
  • Often multiple cotton wool spots.
  • IVFA shows significant capillary dropout and non-perfusion (>10 dd). Photopic flicker ERG abnormal.
  • NVI, NVD, NVE much more common. High rate of secondary neovascular glaucoma. NVI far more common than NVD, NVE.
  
  
  2. Non-ischemic
  • Less severe presentation than ischemic CRVO and better prognosis (40% of cases).
  • VA moderately reduced; often 20/60 to 20/100 range. No APD.
  • Hemorrhaging in all four quadrants.
  • Moderate macular edema.
  • Very few or no cotton wool spots.
  • IVFA shows little to no significant capillary dropout and non-perfusion.
  • NVI and secondary neovascular glaucoma very rare, relatively good prognosis for some visual recovery.
  
  Both can show concurrent cilioretinal artery occlusions. Several findings help to differentiate between the two; IVFA is the definitive test.
• There are no consistently proven adequate treatments to help restore vision in CRVO patients. Canulization with TPA has shown promise in early studies as has radial neurotomy.
• The CVO study asked two questions:
  
  
  1. Is grid laser surgery successful in restoring vision in patients with macular edema?
  2. Should prophylactic PRP be used to prevent NVI in ischemic CRVO?
  
  The answer to both questions proved to be no! Grid laser surgery lessened the macular edema but did not improve vision. Prophylactic PRP was unwarranted compared to careful follow-up (actually worse outcome if neovascularization did develop).
• Since no treatment exists, careful follow-up to watch for neovascular complications is the focus of management. In ischemic cases, see the patient weekly for the first 4 to 6 weeks looking very carefully at the non-dilated iris on each visit. In non-ischemic cases, the first follow-up can be 2 to 3 weeks later. Non-ischemic cases can become ischemic (up to 20%) so still need to follow closely. See monthly after 1 month for the next 3 to 4 months. Complications may develop after this point, but it is more rare for them to do so. If neovascularization develops, PRP must be performed as soon as possible to help prevent neovascular glaucoma.
• VSR is an impending CRVO state with multiple quadrant hemorrhaging but no full blown occlusion (terminology debate).
• ? pressure lowering agents at this stage.

Select picture or text to view a larger image.
	Ischemic CRVO
	Ischemic CRVO
	Non-ischemic CRVO
	Non-ischemic CRVO
	Non-ischemic CRVO
	Early CRVO
	Resolving ischemic CRVO with collaterals
	Capillary dropout from ischemic CRVO
	Collaterals status post CRVO
	Collaterals status post CRVO
	Impending CRVO/venous stasis retinopathy
	Fibrotic neovascularization status post anastomosis surgery for ischemic CRVO

Papillophlebitis An inflammatory variant of CRVO striking otherwise healthy, young adults. Disc edema out of proportion with retinal hemorrhaging (significant disc edema compared to mild four quadrant hemorrhaging). May see disc edema only in early stages. Usually mild VA reduction to around the 20/30 level but can be worse. Vague prodrome of scintillating, colored lights with visual disturbances. Enlarged blind spot on the visual field. Dilated and tortuous veins. Condition is self limiting over the course of several months and a complete recovery is the norm. Is a systemic work-up necessary?

Select picture or text to view a larger image. Papillophlebitis Peripheral blot hemorrahges in papillophlebitis Nerve swelling and venous dilation in papillophlebitis Nerve swelling and venous dilation in papillophlebitis

BRVO (Branch Retinal Vein Occlusion)

• Occlusion of a branch retinal vein by the same mechanisms that occur in CRVO. Rarely ischemic, commonly non-ischemic. Level of impairment depends upon location of the occlusion.
• VA compromised if edema or blood reaches the macula or if there is long-term macular ischemia. Neovascular complications are more rare; NVD and NVE more common than NVI in hemicentral occlusions.
• Spontaneous improvement in vision can occur as the macular edema resolves.
• BRVO study showed that grid laser therapy was effective at improving vision from 3 to 18 months post event. Sheathotomy--controversial.
• Follow monthly for 3 months then consider grid therapy if VA 20/40 or worse and IVFA shows edema instead of macular non-perfusion.

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	Hemicentral BRVO
	Hemicentral BRVO
	Hemicentral BRVO
	BRVO
	BRVO
	BRVO
	Hemicentral BRVO
	Hemicentral BRVO in a patient with glaucoma
	Hemicentral BRVO status post laser treatment
	Hemicentral BRVO status post laser treatment with a macular hole from long-standing macular edema

In both CRVO and BRVO, collateral vessels may form to help drain blood--don't confuse with neovascularization.