Northeast Wisconsin Retina Associates

CLINICAL CONDITIONS

RETINAL VEIN OCCLUSION

Circulatory abnormalities of the retina are common. Most frequently, blockage of one of the veins of the retina is encountered. The medical term for such a blockage is occlusion. Retinal vein occlusions are generally divided into two types: blockage of the main vein which drains blood from the entire retina – central retinal vein occlusion (CRVO); and blockage of one of the smaller tributary veins draining blood from a portion of the retina – branch retinal vein occlusion (BRVO).

retina with branch retinal vein occlusion

Branch retinal vein occlusion (BRVO)



retina with central retinal vein occlusion

Central retinal vein occlusion (CRVO)

Both CRVO and BRVO can cause serious loss of vision. A central vein occlusion is often a more severe event than a branch vein occlusion. Retinal vein occlusions usually result in sudden development of blurred vision. Despite many years of investigation, our understanding of the causes of retinal vein occlusion remains limited. Retinal vein occlusion becomes more common with increasing age. This is likely related to the process of atherosclerosis (age-related changes in blood vessels) which occurs in everyone.

Retinal vein occlusion is somewhat more common in patients with other risk factors for blood vessel disease such as hypertension, diabetes and hyperlipidemia. These are some of the same risk factors associated with blood vessel disease in other parts of the body which can result in heart disease and stroke. Branch retinal vein occlusion is most closely associated with hypertension (high blood pressure). An additional important risk factor for central retinal vein occlusion is glaucoma (elevated eye pressure). Rarely, disorders of the clotting system of the blood can lead to retinal vein occlusion.

Loss of vision due to retinal vein occlusion is based on three mechanisms:

  1. Impairment of retinal circulation. Retinal circulation following a retinal vein occlusion will usually return to normal over many months, however permanent damage to vision often occurs in the interim. Over the last three decades, many treatments have been attempted to more rapidly restore circulation, however to date no form of intervention has proven to be effective.
  2. Bleeding into the tissue of the retina. The hemorrhages within the tissue also resolve slowly over months. No treatment is available for this aspect of the disorder.
  3. Swelling of the macula caused by fluid leakage from the bloodstream originating from damaged capillaries (microscopic blood vessels) in the retina. In many cases of retinal vein occlusion, swelling of the macula (macular edema) causes progressive deterioration of vision and may be the most damaging component of this condition. A number of treatments may provide significant benefit for macular edema due to retinal vein occlusion. These include laser photocoagulation and intraocular injection of various medications detailed in Surgical Procedures.

Additional general considerations in the management of any patient with retinal vein occlusion includes appropriate treatment of other general medical and/or ophthalmologic issues which may be present including hypertension, diabetes, hyperlipidemia and glaucoma.

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