Glaucoma is a disease of the optic nerve, broadly classed as a type of optic neuropathy. It is known as the leading cause of irreversible blindness worldwide as any vision loss from damage to the optic nerve cannot be undone, even with intensive glaucoma treatment. In Melbourne, we are fortunate to have access to a number of ophthalmologists with an interest in glaucoma management and surgery but as glaucoma typically presents with no noticeable symptoms, there is often a delay in referral to a glaucoma specialist.
In simple terms, glaucoma occurs when the pressure within the eye, known as intraocular pressure, rises to a level too high for the health of the optic nerve. This causes damage to the nerve and subsequent loss of vision in the area served by those damaged nerve fibres.
There are two broad classifications of glaucoma:
- open angle glaucoma
- angle closure glaucoma
These refer to the configuration of the iris (the coloured tissue visible at the front of the eye) to the cornea (the transparent dome covering the iris). At the point where the iris meets the cornea is an anatomical structure called the “anterior angle”, an area where the fluid produced within the eye drains out. Intraocular pressure is largely controlled by the balance of fluid production and drainage within the eye. As the name suggests, open angle glaucoma includes those cases where the anterior angle is sufficiently wide but fluid drainage is impeded for other reasons; angle closure glaucoma refers to situations where the iris sits too close to the cornea at the angle, reducing the ability for fluid to be removed.