Eye Pressure?

My patients are sometimes confused about eye pressure. What is eye pressure? The pressure of the fluid inside the eyeball is higher than the pressure of the air outside (atmospheric pressure). That keeps the eyeball firm and round instead of floppy and collapsible. The pressure of the fluid in the eyeball is controlled by production of fluid inside the eye and the drainage of that fluid out of the eye. The drainage of the fluid out of the eye is into the veins of the body, so vein pressure does impact eye pressure. However, this is NOT the same as artery pressure. Artery pressure is what we conventionally think of as blood pressure. Therefore, there is NOT a direct connection between high blood pressure and high eye pressure. That’s why many people who have good blood pressure control might still have high eye pressure. High eye pressure is usually caused by a problem with the drainage of fluid out of the eye. If high eye pressure is not treated and persists for a long time, it can cause the loss of vision (usually side vision first), which is called glaucoma.