At Retina Group of Washington our retina specialists examine and treat patients with retinal vascular disease including retinal artery occlusion and retinal vein occlusion. Retinal Vascular Disease is a term used to describe a number of conditions that can affect the blood vessels and circulation of the retina and result in significant tissue changes with secondary complications and vision loss. In this section, only the two most common retinal vascular disorders-Retinal Artery Occlusion and Retinal Vein Occlusion will be addressed, however there are many other types of retinal vascular disease that our doctors diagnose and treat.
Retinal Artery Occlusion
A Retinal Artery Occlusion can occur in either the Central Retinal Artery or in a Branch Retinal Artery that splits off the Central Retinal Artery. Either artery can become blocked by a clot or “embolus” in the bloodstream.
A Retinal Artery Occlusion is considered a medical emergency and requires immediate attention. When an artery occlusion occurs, it decreases the oxygen supply to the area of the retina nourished by the affected artery, causing permanent vision loss. Most patients who suffer Retinal Artery Occlusions are between the ages of 50 and 80. They notice a sudden, painless loss of vision that can be a complete loss of vision if it is a Central Retinal Artery Occlusion, or can be a partial loss of their visual field if it is a Branch Retinal Artery Occlusion. Sometimes the major loss of vision is preceded by one or more episodes of “Amaurosis Fugax” or transient loss of vision.
Often, patients who have Retinal Artery Occlusions have other significant health problems such as high blood pressure, diabetes, heart arrhythmias or high cholesterol. A cause of Retinal Artery Occlusion in patients over the age of 60 may be due to an underlying inflammatory condition called Giant Cell Arteritis. Some patients who have Retinal Artery Occlusion will also experience a type of Glaucoma as a secondary complication.
If you are diagnosed with a Retinal Artery Occlusion, or if you are identified with any warning sign that you might be at risk for a Retinal Artery Occlusion because we observe the presence of a “plaque” in one or more of your retinal arteries, we will promptly refer you to your Internist or Cardiologist for thorough evaluation and testing including a blood pressure evaluation, electrocardiogram (EKG), fasting blood glucose, lipid and cholesterol levels, and hyper viscosity studies in order to help better understand your overall health.
Treatment of Retinal Artery Occlusions
A Central Retinal Artery Occlusion has typically been considered an emergency. It was felt that, if the clot or ‘embolus” could be dislodged within 90 minutes of the blockage, it would be possible to preserve vision. To accomplish this, a number of methods have been tried to dilate or widen the artery or to free the embolus including breathing into a paper bag to increase your blood carbon dioxide levels so that blood vessels dilate, massaging the eye, draining some Aqueous Humor fluid from the front of the eye and using various “clot busting” medications to lower the Intraocular Pressure to decrease internal eye resistance to blood flow as well as attempts to dissolve the clot. Some eye physicians might attempt these treatments if the occlusion were less than 24 hours old, however, large scale studies do not indicate that the final visual outcome of patients treated aggressively is significantly different than those treated conservatively.
Retinal Vein Occlusion
A Retinal Vein Occlusion can occur in the Central Retinal Vein or in a Branch Retinal Vein. Retinal Vein Occlusion occurs when the circulation of a retinal vein becomes blocked.
This blockage damages the vein, leading to retinal hemorrhages, swelling and ischemia (a lack of oxygen) in the Retina. Retinal Vein Occlusion occurs equally in women and men and mostly after the age of 60, and especially on those patients with diabetes, hypertension or cardiovascular disease.
The visual symptoms of Retinal Vein Occlusion can vary greatly in severity from one person to the next. The symptoms are also quite dependent on whether it is a Central Retinal Vein or Branch Retinal Vein that has become occluded. Typically, patients experience a sudden onset of blurred or a “missing area of vision” if a branch retinal vein or central retinal vein has become occluded. Some patients who have Retinal Vein Occlusion will also experience a type of Glaucoma as a secondary complication. Patients who experience a Branch Retinal Vein Occlusion often notice a gradual improvement in their vision as the retinal swelling resolves. Unfortunately, visual recovery from a Central Retinal Vein Occlusion is less likely.
Diagnosis of Retinal Vein Occlusion
To diagnose a Retinal Vein Occlusion your pupil will be dilated so that the retina specialists can directly observe the retina using instruments with a high magnification “fundus lens” so that fine detail can be examined. It is usually necessary to have an Fluorescein Angiogram (IVF) to study the blood circulation in the retina, as well as an Optical Coherence Tomogram (OCT) to detect the presence and severity of Macular Edema, or swelling.
Treatment of Retinal Vein Occlusion
The main objectives of treating Retinal Vein Occlusion are to avoid and treat secondary complications. If there are areas of the retina that have been deprived of oxygen, “chemical signals” are released that can stimulate the formation of “new blood vessels” or “neovascularization.” These new blood vessels are not “normal” in that they are extremely fragile and easily broken, resulting in hemorrhage and scarring of the retina with resulting vision loss. The new blood vessels may also cause a type of secondary glaucoma, called Neovascular Glaucoma. If you develop neovascularization, it will be necessary to Vascular Endothelial Growth (VEGF) Inhibitor Injections such as Lucentis® Injections, Eylea® Injections or Avastin® Injections to stop the growth of these delicate blood vessels as well as possibly laser photocoagulation treatment.