What is Ischemic Optic Neuropathy (AION)?
This is the most common cause of sudden decreased vision in patients older than 40 years. We do not see with our eyes. We see with part of our brain that is capable of interpreting visual signals sent back from the eyes. This is located at the back of our head (the occipital lobes). Information is transmitted from the eyes to the brain via the optic nerves. These nerves are composed of the long tube extensions (axons) of cells (ganglion cells) located within the inner lining of the eye (the retina) that exit the back of the eye at the optic disc. Each of the optic nerves receives blood supply from branches of the ophthalmic artery within each eye socket. The optic disc has a unique blood supply (the posterior ciliary arteries). Loss of blood supply within the posterior ciliary arteries deprives the optic nerve tissue of oxygen and results in damage to part or all of the optic nerve. This is a small “stroke” in the optic nerve. It is painless. Patients may become aware of decreased visi
