Retinal Artery and Vein Occlusion

Related conditions: Central retinal artery occlusion, branch retinal artery occlusion, central retinal vein occlusion, branch retinal vein occlusion

Background

The retina gets its oxygen and nutrients from the retinal artery tree. The central retinal artery delivers all blood to the eye. This artery then splits into multiple branches that bring blood to the far reaches of the retina. After the retina uses the oxygen and nutrients from the blood, it creates waste products that are removed from the eye by veins. Just like the arterial system, there are multiple branch veins that ultimately drain into a single, large central retinal vein, which removes the depleted blood from the eye.

If any branch of the system becomes clogged or occluded, vision may be affected. If an artery becomes blocked, no blood is delivered to the portion of the retina served by that artery. This is similar to an ischemic stroke. Depending on how severe the clog is and how long it lasts, the retina may become permanently damaged and vision severely impaired.

When a vein is occluded, the used blood cannot drain from the area it serves, and the vessels leading up to the occlusion become engorged. This causes blood to leak into the retina, which can become swollen like a sponge. More important, since the old blood cannot be drained from a portion of the retina, fresh blood cannot be delivered to that area either. Therefore, the retina is essentially starving. As such, vision may be significantly reduced.

Using angiography (see above), we can evaluate the circulation of your retina in our offices as well as calculate the thickness of your retina using ocular coherence tomography. If you have an artery occlusion, there are limited treatment options. However, since this would mean you have an embolism or thrombosis in your arterial system, we would work closely with your primary care physician to find the source in order to prevent other clots from forming elsewhere in your body.

Based on your vision and exam findings, if you have a vein occlusion, there are multiple treatment options available. The final outcome is often determined by the initial vision exam in our office, which is a marker of the severity of the vein occlusion.

Most Common Symptoms

• Blurry vision that is either central or peripheral
• A dark shadow or shade over a segment of your visual field that doesn’t go away

Potential Complications

• Severe vision loss
• Cystoid macular edema
• Neovascular glaucoma
• Vitreous hemorrhage
• Stroke

Treatment

• Macular edema from vein occlusions can be treated with intravitreal injections/implants.
• LASER treatment for macular edema can be used in some vein occlusions.
• Neovascular changes in vein or artery occlusions can be treated with pan-retinal pholocoagulation (LASER).