Branch retinal vein occlusion (BRVO)

I.        Describe the approach to establishing the diagnosis

A.     Describe the etiology of this disease

1.      Exact mechanisms unknown: 

2.      The retinal vein and artery share a common adventitial sheath

3.      If arteriosclerotic changes are found in the artery which often lies on top of the branch retinal vein, a thrombus may be the result of a thrombosis in the retinal vein

B.     Define the relevant aspects of epidemiology of the disease

1.      Occur more commonly in patients 50 years or older

2.      Increased association with diabetes, hypertension, hyperlipidemia

C.    List the pertinent elements of the history

1.      History of systemic diseases such as diabetes, hypertension

2.      History of ocular disease: primary open-angle glaucoma

3.      Visual acuity impairment, blurred central vision or presence of floaters

D.    Describe pertinent clinical features

1.      Measure intraocular pressure in both eyes

2.      Evaluate the fellow eye for glaucomatous changes

3.      Dilated fundus exam with stereoscopic and biomicroscopic evaluation

4.      Assess the fundus for macular edema, retinal hemorrhages, cotton-wool spots, retinal neovascularization, capillary dropout

5.      Collateral vessels may occur around the occlusion site of the branch retinal vein occlusion, or to an adjacent unaffected retinal watershed (i.e., across the raphe?)

E.     Describe appropriate laboratory testing for establishing the diagnosis

1.      The following tests are not required for diagnosis but may be important to evaluate whether the affected eye has the ischemic or non-ischemic type of BRVO to determine if treatment is considered

a.      Fundus photographs

b.      Fluorescein angiography especially for macular edema

II.      Define the risk factors

A.     Systemic diseases: hypertension, diabetes, systemic inflammatory disorders (e.g., systemic lupus erythematosus), hyperlipidemia

B.     Ocular disease: primary open-angle glaucoma

C.    Local inflammation (toxoplasmosis, etc.)

III.    List the differential diagnosis

A.     Diabetic retinopathy

B.     Radiation retinopathy

C.    Hemi central retinal vein occlusion

D.    Juxtafoveal telangiectasia

E.     Epiretinal membrane

IV.   Describe patient management in terms of treatment and follow-up

A.     Initial observation for most patients

B.     In following the patients with the ischemic type of BRVO, the presence of retinal neovascularization or hemorrhage would warrant scatter photocoagulation (in distribution of BRVO)

C.    After a period of observation of 3 to 6 months, patients with persistent macular edema and visual acuity 20/40 or worse, should consider focal laser photocoagulation

D.    Glaucoma may need treatment

E.     Describe medical therapy options

1.      Good blood pressure control

2.      Treatment of dyslipidemia

3.      Treatment of diabetes, if present

F.     Describe surgical therapy options

1.      Laser photocoagulation

a.      Consider for eyes with vision 20/40 or worse

b.      Focused on edematous retina

c.      Applied with a light grid pattern using 50 to 100 microns spot size

d.      Light grey color of the laser spots

e.      Leaking microvascular abnormalities are treated directly and collaterals vessels are avoided

2.      Scatter laser photocoagulation for retinal neovascularization and vitreous hemorrhage

a.      Apply to areas of nonperfusion adjacent to the neovascularization

b.      Apply with 200 to 500 microns spot size, using 0.07 to 0.10 second duration

c.      Moderate intensity, apply the burns approximately 1 burn width

3.      Intravitreal corticosteroids are currently being investigated for the treatment of macular edema associated with BRVO

V.   List the complications of treatment, their prevention and management

            A.     Accidental or inadvertent treatment of the fovea with laser

            B.     Reduced central contrast sensitivity in region of scatter laser 

            C.    Choroidal neovascularization from laser burn site