A retinal vein occlusion occurs when small veins in the retina become blocked. These veins carry blood away from the retina but the blockage can damage the blood vessels of the retina, the layer of tissue at the back of the inner eye that converts light images to nerve signals and sends them to the brain.
There are two types of Retinal Vein Occlusion
- Branch Retinal vein occlusion (BRVO) affecting a branch of the central retinal vein
- Central Retinal vein occlusion (CRVO) affecting the central retinal vein
There are a number of causes of Retinal Vein Occlusion and these can include:
- High blood pressure
- Blood disorders
An Optician or GP can detect the signs of vein occlusion. If a vein occlusion is suspected you will be referred to a Retinal Consultant Specialist who has a number of tests or examinations that can be used in the diagnosis of RVO:
- Visual Acuity: measures how well you see at various distances
- Slit Lamp Examination: examines your eye under high magnification
- Tonometry: measures the pressure in the eye
- Eye Examination: drops are used to dilate the pupil and examine the retina in detail
- Amsler Grid: a lined grid used to check for distorted or missing lines
- Colour Fundus Photography: photography of the fundus (inner lining of the eye) to produce a sharp photograph of the retina and the blood vessels
- Fluorescein Angiogram: a special dye fluorescein is injected into a vein in the arm, as the dye passes through the blood vessels in the retina a photograph of the eye is taken
- Optical Coherence Tomography: 3D scans of the layers of the macula part of the retina
There are treatment options to manage RVO and the resulting complications.
- Macular oedema – fluid swelling in the macula
- Macular ischaemia – lack of blood supply
- Neovascularization- abnormal growth of new blood vessels
Injections are used to treat swelling of the macula due blood or fluid. The goal of treatment is to prevent further loss of vision. Although some patients have regained vision, the medication may not restore vision that has already been lost and may not ultimately prevent further loss of vision caused by the disease.
Ozurdex is a biodegradable implant containing the corticosteroid dexamethasone. Corticosteroids, such as dexamethasone, block chemical pathways that lead to inflammation, leakage from the retinal blood vessels and oedema (swelling) of the retina. You may require up 2-3 injections a year.
In Branch Retinal Vein Occlusion laser photocoagulation is a proven therapy for new blood vessels in vein occlusions. Laser treatment can cause stabilisation or, at times, regression of the new blood vessels.
This treatment, while important in helping to prevent further visual loss, is not usually associated with improvement in vision.
Following The Procedure
Depending on the treatment you receive, your Consultant will advise you on any follow-up care required or post-treatment instructions.
The Retinal Department at the Mater Private Eye Centre works as a multidisciplinary team delivering treatments and surgery to 5,000 patients annually with routine and complex eye conditions.