Artery & Vein Occlusions
Retinal artery occlusion
A retinal artery occlusion is a blockage of one of the large blood vessels that brings oxygen-rich blood from the heart to the retina. This can happen to the central retinal artery or one of its branches, resulting in a sudden, severe loss of all or part of the vision in the affected eye.
The blockage is often caused by a small cholesterol plaque or blood clot and the risk factors for retinal artery occlusion are similar to the risks for having a stroke. These risk factors include but are not limited to disease of the carotid arteries in the neck, high cholesterol, high blood pressure, valvular heart disease, and clotting disorders.
This condition is diagnosed with a dilated eye exam and often a dye test called fluorescein angiography which highlights the lack of proper flow in the affected blood vessel.
There is unfortunately no proven treatment for retinal artery occlusions. An important part of management of this condition is evaluation for stroke risk factors, which frequently involves an emergency room visit for expedited care.
Retinal vein occlusion
Retinal vein occlusion refers to a blockage or slow-down of blood flow through one of the blood vessels in the retina that is taking the blood out of the eye and back towards the heart. This can happen to the central retinal vein or one of its branches, and leads to an abrupt decrease in vision if it involves the macula at the center of the eye. If it does not involve the macula it may not have any associated symptoms.
The risk factors for a retinal vein occlusion include high blood pressure, glaucoma, heart disease, obesity, and clotting disorders. It can occur at any age, but most commonly happens after the age of 50.
It is diagnosed with a dilated eye exam. A non-invasive imaging test called optical coherence tomography is used to identify if there is any associated swelling of the retina. A dye test called fluorescein angiography is often used in diagnosis to identify the blood vessel involved and determine the extent of damage to the retina.
The treatment of retinal vein occlusion depends on the severity. Some cases do not require treatment, but if the central vision is involved, then treatment is often beneficial. Treatments are aimed at reducing swelling, bleeding, or abnormal blood vessel growth, but do not actually remove the blockage. The most common treatment is administration of a medicine as an injection into the eye in order to reduce swelling of the retina and prevent the growth of abnormal blood vessels. Laser treatment is sometimes employed in resistant or advanced cases.