Retinal Vein Occlusion

What is Retinal Vein Occlusion?

The front of the eye contains a lens that focuses the images on the inside of the back of the eye. This area is the retina. The retina is where the eye focuses the images we see. It is covered with special nerve cells that convert light into signals sent through the optic nerve to the brain, where they are recognized as images. The conditions affecting the retina affect the ability to see.

The arteries carry blood from the heart to other parts of the body, and the veins carry the blood back to the heart. An obstruction in an artery or vein is called an occlusion or stroke. When blood flow from the retina is blocked, it is often because a clot blocks retinal vein. This condition is called retinal vein occlusion.

Nerve cells need a constant supply of blood to provide oxygen and nutrients. Blood vessels provide this supply. In a stroke, a small blood clot blocks the flow of blood through one of the arteries of the brain, and the area that does not take blood is damaged.

This same type of damage can occur anywhere on the body. When a vein of the retina is blocked, it cannot drain blood from the retina. This leads to hemorrhages and leakage of fluid from the blocked blood vessels.

There are two types of retinal vein occlusion:

  • Obstruction of the central vein of the retina (CRVO) is the occlusion of the main retinal vein.
  • Obstruction of the branch vein of the retina (BRVO) is the occlusion of one of the smaller branch veins

Before retinal vein occlusion treatment:


After retinal vein occlusion treatment

  • Macular edema: The macula is the small, central area of the retina that allows sharp, detailed vision, such as that necessary for reading.
  • Neovascularization: Retinal vein occlusion can cause the retina to develop new, abnormal blood vessels, a condition called neovascularization. These new vessels can leak blood or fluid into the vitreous. Small spots or clouds, called floaters, may appear in the field of vision; with severe neovascularization, the retina can detach from the back of the eye.
  • Neovascular glaucoma: New blood vessels in some parts of the eye can cause pain and a dangerous increase in pressure inside the eye.
  • Blindness: Complications of retinal vein occlusion, especially if untreated, can lead to irreversible loss of vision.

Obstruction of the vein of retinal vein occurs when a blood clot blocks the vein. Sometimes it happens because the veins of the eye are too narrow. It is more likely to occur in people with diabetes and possibly high blood pressure, high cholesterol levels or other health problems that affect blood flow.

Symptoms of retinal vein occlusion range from subtle to very obvious. There is painless blurring or loss of vision. It almost always happens to a single eye. At first, blurring or loss of vision may be slight, but it gets worse overthe next few hours or days. Sometimes there is complete loss of vision almost immediately.

If these symptoms occur, it is important to schedule an appointment with your doctor as soon as possible. Retinal vein occlusion often causes permanent damage to the retina and loss of vision.

  • Optical Coherence Tomography (OCT): This is a high-resolution image of the retina taken by an ophthalmoscope scanning resolution of 5 microns. These images can determine the presence of edema by measuring the thickness of your retina. The doctor will use OCT images to objectively document the progression of the disease throughout your treatment.
  • Ophthalmoscopy: The changes caused byretinal vein occlusion can be seen by examination of the retina with an organ called an ophthalmoscope.
  • Fluorescein angiography: This is a test procedure in which a dye injected into a vein of the arm travels to theretinal blood vessels. Special photos allow the doctor to see the vessels.

Unfortunately, there is no way actually to unblock the retinal veins. However, your doctor may treat any health problems that appear to be related to retinal vein occlusion.

Vision may return to some eyes that have had retinal vein occlusion. About 1/3 has some improvement, about 1/3 remains the same, and about 1/3 gradually improves, but it may take a year or more to find out the final result. In some cases, blocked vessels will lead to fluid accumulation in the retina. In others, they can provoke the formation of new blood vessels.

  • Intravitreal injection of anti-vascular endothelial growth factor (VEGF) drugs: These drugs target VEGF, which is an important growth factor that causes macular edema.
  • Intravitreal injection of corticosteroid drugs: These drugs fight the inflammatory components that lead to edema.
  • Focal lasertreatment: This treatment provides lasers to areas with edema to cause a decrease in it.
  • Pan-retinal photocoagulation treatment: This treatment is used when patients have the formation of new blood vessels after the retinal vein occlusion.

Return visits are recommended to monitor the progression of your disease. It is important to detect changes in your condition and formulate treatment plans as needed. It is also important to tell your primary care doctor about the obstruction of the vein of the retina so that he can evaluate and treat any underlying systemic diseases.

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