Open angle glaucoma causes a gradual and irreversible reduction in vision. Glaucoma affects the inside of the eye at a structure called the optic nerve. Early changes to the optic nerve can only be detected using specialised tests as early glaucoma does not cause any symptoms of pain or vision loss. The first line of defense is the regular and timely use of special eye drops that have the effect of lowering eye pressure. The drops work by either reducing the amount of fluid produced or increasing the fluid outflow. Your Practitioner may prescribe one or more drops in order to effectively control eye pressure. It is essential to adhere to the recommended use of the drops in order to minimise sight loss.