Retinal Vein Occlusion
In this photo, the retinal vein occlusion has prevented blood from flowing out of the eye. Instead, the blockage means that blood and fluid spill out into the retina, giving rise to this appearance.
What is Retinal Vein Occlusion?
Blood vessels are important to the health and function of your retina. Arteries deliver fresh blood and oxygen to the retina while veins drain the used blood and waste products away.
In a retinal vein occlusion (or RVO), the veins become blocked. This blockage causes two problems.
Firstly, the blocked blood and fluid are forced out of the blood vessels, causing your retina to become waterlogged and affecting its function. This swelling commonly occurs in the macula, which is the central part of the retina. This is called cystoid macular oedema (or CMO).
Secondly, the blockage can prevent fresh blood from flowing properly through the blood vessels. The retina becomes starved of oxygen and stops working. This is called retinal ischaemia.
To stop this ischaemia, the retina tries to repair this blood supply by growing new blood vessels. This is called retinal neovascularization. These blood vessels are abnormal and can cause eye pressure problems, bleed or turn into scar tissue that can cause the retina to detach. If this is not treated, there is a risk that you may lose your sight.
What are the symptoms of retinal vein occlusion?
The symptoms that you have will depend on which veins are blocked and the severity of the blockage. In a central retinal vein occlusion (or CRVO), the main vein that drains the retina becomes blocked. Most people notice some blurring of their vision due to CMO. If very severe, the vision will be poor.
With a branch retinal vein occlusion (or BRVO), one of the smaller retinal veins becomes obstructed. Your vision may be normal if the blocked vein and CMO does not affect your macula, which is responsible for your central vision.
How do you treat retinal vein occlusion?
It is important to investigate your eyes before treatment. This is usually done with retinal scans and sometimes using angiography, where a dye is injected into your arm and photographs of the retinal blood circulation are taken. This allows me to accurately assess any damage present and demonstrate this to you.
These investigations may incur an additional cost from the Nuffield Hospital. I will not charge a separate fee for reporting on investigations as I believe that these are essential to a proper and comprehensive consultation.
Mild cases of CMO can be observed if your vision is not affected. If there is further deterioration or your vision is reduced, then the CMO can be treated with a course of injections of drugs into the affected eye. These drugs stop the damaged blood vessels from leaking. This treatment is usually provided by the NHS on an outpatient basis (please see link below).
If severe retinal ischaemia is present, the laser treatment to the retina decreases the chance of retinal neovascularisation.
Bleeding inside the eye or retinal detachment may require surgery.
What does treatment or surgery involve?
CMO can be treated by injections into the eye, performed with local anaesthetic drops as an outpatient procedure. After the surface of your eye is numbed, a cleaning solution is used to disinfect the area. Your eyelids are gently held open and the drug is delivered through the white of the eye. The entire process lasts around 5 minutes. There is no special aftercare required.
Laser treatment for severe retinal ischaemia (loss of blood supply) is called panretinal photocoagulation (or PRP). It is an outpatient procedure and the setup is very similar to the examination at your consultation. The pupil in your affected eye will be dilated and anaesthetic drops will be used to numb the surface of your eye. This allows a temporary lens to be placed against your eye that helps to keep your eye still. You will notice bright flashes of light when the laser is used. This treatment can last up to 30 minutes and there is no special aftercare required.
Surgery for bleeding or retinal detachment is usually done as a day case under local anaesthesia. The length of the operation depends on the severity of damage present. It involves a procedure known as vitrectomy, where microscopic instruments are introduced through the white of the eye to remove any blood or scar tissue and deal with any retinal detachment.
Where will treatment or surgery be performed?
Laser treatment, injections and surgery are performed at the Nuffield Health Bristol Hospital.