Branch retinal vein occlusion
 

There is tortuosity of the retinal vein (superotemporal vein is the most commonly involved) with dot  and blot and flamed haemorrhages along the nerve fibre layer. The macula may show macula oedema.  Look for any peripheral neovascularization or fibrosis in the peripheral retina. (Note: examine the nasal  side of the retina to be certain that the occlusion is branch and not hemi-retinal vein occlusion). Examine the eye for: hypertensive retinopathy such as artero-venous nipping sectorial pan-photocoagulation for peripheral neovascularization macular laser scars from focal photocoagulation for macular oedema

Questions:

1. What are the causes of visual loss in branch retinal vein occlusion?

Answer
The main cause of visual loss is macular oedema and this may be exudative or ischaemic.
Other causes include vitreous haemorrhage secondary to peripheral neovascularization and tractional retinal detachment.

2. What is the recommendation for macular oedema according to the Brach Retinal Vein Occlusion Study?

Answer
The Study looks at the benefit of argon laser photocoagulation for patients with macular oedema secondary to branch retinal vein occlusion. In the recommendation: no treatment is considered for at least 3 months as half of the patients retain a visual acuity of 6/12 or better at one year follow-up. If macular oedema reduces vision to 6/12 or worse at 3-month follow-up and the fluorescein angiography shows no signs of macular ischaemia, argon laser in a grid pattern to areas of capillary leakage can improve the vision. 60% of treated eye compared with 34% of untreated eyes have a vision of 6/12 or better at 3-year follow-up).

3. What is the benefit of prophylactic laser photocoagulation for patient with ischaemic branch retinal vein occlusion?

Answer
The Branch Retinal Vein Occlusion Study shows that patients who were treated with sectorial pan-photocoagulation has a reduced risk of vitreous haemorrhage. However, as most branch retinal vein occlusion do not develop neovascularization, the Study recommends photocoagulation only in eyes which have developed neovascularization.

 

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