What is NAION?
NAION, also called NAAION (non-arteritic anterior ischaemic optic neuropathy), is a part of the optic nerve that carries signals from the eye to the brain, allowing us to see. It's a condition that causes a sudden, painless decrease in vision in one eye; it usually affects people over 50. It's a condition where the blood vessels supplying the front of the optic nerve become blocked. This causes a lack of blood supply (ischaemia), which affects the oxygen supply to the optic nerve.
The effects of NAION on sight can be mild for some people and more severe for others. Some people retain their very central vision, but often symptoms include blurred vision, darker or dimmer vision, colour vision problems, and loss of peripheral (side) vision.
There is no treatment for NAION itself. However, treatment may be appropriate for any underlying cause identified, such as blood pressure anomalies (high or low blood pressure), diabetes, raised cholesterol levels, and sleep apnoea. Any treatment aims to protect the person's general health and to prevent NAION from occurring in the other eye.
