Retinal vein occlusion (RVO)
Retinal vein occlusion is a blockage of the small veins that carry blood away from the retina. The retina is the layer of tissue at the back of the inner eye that converts light images to nerve signals and sends them to the brain. The blockage may concern the central vein of the retina or one of its branches. Branch retinal vein occlusion is two to three times more common than central retinal vein occlusion.
Retinal vein occlusion is most often caused due to the hardening of the arteries (atherosclerosis) and the formation of a blood clot.
Occlusion of smaller veins in the retina often occurs in places where retinal arteries that have been thickened or hardened by atherosclerosis cross over and place pressure on a retinal vein.
Patients who have been diagnosed with retinal vein occlusion in one eye, run an increased risk (9-15%) of experiencing the same complication in the same or the other eye in the next 5 years. Uncontrolled high blood pressure (hypertension) may be related with the recurrence of the retinal vein occlusion in the same or the other eye.
Hyperlipidemia is the most common etiology in patients under 50 years old and is responsible for the blockage in 50% of older patients. Diabetes is also associated with retinal vein occlusion. This is probably caused due to the increased cardiovascular risk factors (e.g. 70% of patients with type II diabetes suffer from high blood pressure).
- High blood pressure (64%)
- Hyperlipidemia (50%)
- Smoking (50%)
- Thrombophilia, autoimmune disorders
- Other topical factors: Glaucoma, retinal vasculitis
The likelihood of appearance of the above mentioned systemic diseases increases with age and therefore retinal vein occlusion most often affects older people.
The most common complication is accumulation of fluid in the macula (macular edema). Another complication is glaucoma (called neovascular), which is caused due to the development of new vessels in the iris and accumulation of fluid in the macula (macular edema).
Acute, painless loss of vision or part of field of view of an eye.
- Measurement of the visual acuity
- Pupillary response
- Slit-lamp examination
- Measurement of the intraocular pressure
- Dilated pupil fundoscopy
- Fundus photography
- Optical coherence tomography of the retina
- Fluorescein angiography
- Other tests – General check up
- Blood pressure measurement, blood test for diabetes and hyperlipidemia (cholesterol, triglycerides)
- Test to check for increased blood clotting in patients under 40.
Frequent monitoring is required to ensure that any complications, such as glaucoma, which usually appears after the first 3 months, will be diagnosed in time.
The treatment of the systemic disease (diabetes, high blood pressure, hyperlipidemia) is required to prevent the occlusion of another vein of the same eye or of the other eye.
A small percentage of patients experiences spontaneous improvement in visual acuity without treatment. Treatment is recommended for patients with significant reduction of visual acuity because of macular edema.
The treatment consists of:
- Intravitreal injection of anti-vascular endothelial growth factor (anti-vegF)
- Laser treatment in the macula, if the macular edema does not respond to the injections.
- Laser treatment on the retina, in the case of a neovascular glaucoma.
- Corticosteroid intravitreal implant for patients who do not respond to intravitreal injections of anti-vascular endothelial growth factors
- Administration of aspirin as an anticoagulant in certain cases.
The prognosis varies and is related to the level of visual acuity at the time of diagnosis and the presence of any systemic diseases.
It has been found that patients with retinal vascular disease (vein occlusion or artery occlusion) face an increased risk of death from cardiovascular events and stroke in the next 10 years.
- Low fat diet
- Regular exercising
- Avoid being overweight
- Cessation of smoking
- Regulation of other conditions: Diabetes, hypertension, hyperlipidemia