Retinal Vein Occlusion
Retinal vein occlusion [central (CRVO), branch (BRVO)]
CRVO – thrombus of central retinal vein near lamina cribosa (Green, 1981) BRVO – thrombus at arterioveinous crossing point from atherosclerosis (Frangieh, 1983)
CRVO – hypertension, open angle glaucoma, diabetes mellitus (The Eye Disease Case-Control Study Group, 1996) BRVO – hypertension, cardiovascular disease, open angle glaucoma, and high body mass index (not diabetes mellitus) (The Eye Disease Case-Control Study Group, 1993)
CRVO – A thrombus forms at the central retinal vein near the lamina cribosa (Green, 1981) BRVO – Arterial compression onto veins causes turbulence which may lead to endothelial cell damage and thrombus formation (Frangieh, 1983)
Retinal vein occlusions can cause retinal ischemia, neovascular complications such as glaucoma, vitreous hemorrhage and retinal traction, and macular edema.
Maximal management of associated risk factors.
Patients often report a history of cardiovascular risk factors including a history of diabetes mellitus and hypertension.
To diagnose and monitor for associated sequelae, clinicians must perform a thorough undilated slit lamp anterior segment examination with gonioscopy and dilated fundus examination with ophthalmoscopy. In addition, fluorescein angiography and optical coherence tomography may supplement clinical decision making.
Retinal vein occlusions demonstrate variable degrees of intraretinal hemorrhage, cotton wool spots, macular edema, subretinal fluid, collateral vessels (chronic), iris and retinal neovascularization, dilated and tortuous veins, and ghost vessels.
Common: Central or peripheral monocular vision loss Less common: Transient visual obscurations or asymptomatic
Since the differential diagnosis is limited, retinal vein occlusions are often diagnosed with history and physical examination alone.
Fluorescein angiography may be used to determine the degree of retinal ischemia and diagnose macular edema. This may be important for prognostic reasons and to predict the development of sequelae. Optical coherence tomography may be used to diagnose macular edema and gauge response to treatment.
In older patients with cardiovascular risk factors, no laboratory tests are needed. In atypical cases such as younger patients and bilateral or recurrent retinal vein occlusions, laboratory tests such as a complete blood count, fasting serum glucose, serum protein electrophoresis, homocystein, serum viscosity, and thrombophilic screening (factor V Leiden mutation, protein C or S deficiency, antithrombin III deficiency, antiphospholipid antibodies) may be considered.
Ocular ischemic syndrome, diabetic retinopathy, human immunodeficiency virus (HIV) retinopathy, hypertensive retinopathy, retinopathy related to blood dyscrasias
No effective treatment is available for retinal vein occlusions. However, the iris or retinal neovascularization or macular edema may be managed with medical or laser intervention.
Medical therapy can limit complications from retinal vein occlusions. Off-label anti-VEGF intraocular injections can cause regression of iris neovascularization (Ciftci, 2009) and macular edema (Spaide, 2009; Kondo, 2009). In addition, the SCORE study demonstrated the benefit of triamcinolone acetonide for macular edema secondary to central retinal vein occlusions (vs. sham) (Ip, 2009) but did not demonstrate benefit for branch retinal vein occlusions (vs. focal laser) (Scott, 2009).
Medical follow up
Ischemic retinal vein occlusions can cause iris or retinal neovascularization in addition to macular edema and should be observed with an undilated iris and angle examination followed by a dilated fundus examination on a period basis.
The Central Retinal Vein Occlusion Study supported panretinal photocoagulation for iris neovascularization after it occurs. (CVO Study Group N Report, 1995) It did not support grid photocoagulation for macular edema. (CVO Study Group M Report, 1995) The Branch Vein Occlusion Study supported the use of grid laser photocoagulation of edematous area. (BVO Study Group, 1984) In addition, The BVO Study Group recommended sectoral panretinal photocoagulation for the development of retinal neovascularization. (BVO Study Group, 1986)
Surgical follow up
Complications associated with intravitreal injections include infection, bleeding, retinal detachment, cataract, and both infectious and sterile uveitis; however, these complicatations remain relatively rare. Triamcinolone acetonide can also cause a steroid-induced glaucoma.
The prognosis is highly variable depending on the location of the retinal vein occlusion, degree of ischemia, and development of sequelae.
Green WR, Chan CC, Hutchins GM, Terry JM. Central retinal vein occlusion: a prospective histopathologic study of 29 eyes in 28 cases. Retina. 1:27-55, 1981.
The Eye Disease Case-Control Study Group. Risk factors for central retinal vein occlusion. Archives of Ophthalmology. 114(5):545-54, 1996.
The Eye Disease Case-Control Study Group. Risk Factors for branch retinal vein occlusion. American Journal of Ophthalmology. 116(3):286-96,1993.
Frangieh GT, Green WR, Barraquer-Sommers E, et al. Histopathologic study of nine branch retinal vein occlusions. Archives of Ophthalmology. 100:1132-40, 1982.
The Central Vein Occlusion Study Group: Evaluation of grid-pattern photocoagulation for macular edema in central vein occlusion: the CVOS Group M Report. Ophthalmology 102:1425-33, 1995.
The Central Vein Occlusion Study Group: A randomized clinical trial of early panretinal photocoagulation for ischemic central vein occlusion: the CVOS Group N Report, Ophthlamology 102:1434-44, 1995.
Branch Vein Occlusion Study Group. Argon laser photocoagulation for macular edema in branch vein occlusion. American Journal of Ophthalmology. 98:271-82, 1984.
Branch Vein Occlusion Study Group. Argon laser scatter photocoagulation for prevention of neovascularization and vitreous hemorrhage in branch vein occlusion. Archives of Ophthalmology. 104:34-41, 1986.
Ciftci S, Sakalar YB, Unlu K, et al. Intravitreal bevacizumab combined with panretinal photocoagulation in the treatment of open angle neovascular glaucoma. European Journal of Ophthalmology. 19(6):1028-33, 2009.
Spaide RF, Chang LK, Klancnik JM, et al. Prospective study of intravitreal ranibizumab as a treatment for decreased visual acuity secondary to central retinal vein occlusion. American Journal of Ophthalmology. 147(2):298-306, 2009.
Kondo M, Kondo N, Ito Y, et al. Intravitreal injection of bevacizumab for macular edema secondary to branch retinal vein occlusion. Retina. 29:1242-48, 2009.
Ip MS, Scott IU, VanVeldhuisen PC, et al. A randomized trial comparing the efficacy and safety of intravitreal triamcinolone with observation to treat vision loss associated with macular edema secondary to central retinal vein occlusion: the Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) study report 5. Archives of Ophthalmology. 127(9):1101-14, 2009.
Scott IU, Ip MS, VanVeldhuisen PC, et al. A randomized trial comparing the efficacy and safety of intravitreal triamcinolone with standard care to treat vision loss associated with macular Edema secondary to branch retinal vein occlusion: the Standard Care vs Corticosteroid for Retinal Vein Occlusion (SCORE) study report 6. Archives of Ophthalmology. 127(9):1115-28, 2009.