6. Retinal Vein Occlusions
The American Society of Retina Specialists explains how blocked veins (occlusions) can cause eye strokes. “Retinal vein occlusions occur when there is a blockage of veins carrying blood with needed oxygen and nutrients away from the nerve cells in the retina. A blockage in the retina’s main vein is referred to as a central retinal vein occlusion (CRVO), while a blockage in a smaller vein is called a branch retinal vein occlusion (BRVO).”
The branch retinal vein occlusion begins with pain-free sudden vision loss, or it can go undetected if the blockage manifests as tiny vision “floaters” caused by leaking blood vessels.
5. Retinal Arterial Occlusions
Much like the retinal vein occlusion, a retinal arterial occlusion is a blockage of the retinal artery. Significant vision loss can happen when oxygen can’t get to the eye to nourish nerve cells supported by this essential pathway. Also, as with a retinal vein block, the main symptom of retinal arterial occlusion is sudden and painless loss of vision.
The outcome of a blocked retinal artery depends on which artery has shut down. If the main artery (the ophthalmic artery) is the cause of blockage to the retina, it can lead to significant vision loss. This condition is called a central retinal arterial occlusion (CRAO).
4. Ischemic Optic Neuropathy
The American Academy of Ophthalmology describes ischemic optic neuropathy (ION) as one that occurs “when blood flow to the optic nerve is reduced or blocked, the nerve does not get enough oxygen or nutrition. The optic nerve stops working properly, and eventually dies.” If the optic nerve dies, there’s no repairing it. As a result, loss of vision becomes permanent.
Symptoms of ischemic optic neuropathy are sudden loss of central or peripheral vision. Often this is experienced as quick blips where your vision is blocked for a few seconds and then restored again, known as transient ischemic attacks. Someone with this symptom should get immediate medical care before the optic nerve suffers irreversible damage.