Glaucoma is a group of conditions characterised by a progressive loss of vision. Glaucoma is classified as primary or secondary. The most common type of glaucoma, called “primary” open angle glaucoma, is a chronic disturbance of the normal fluid pressure inside the eye and is generally age-related. “Acute” or secondary closed angle glaucoma is more rare and is identified by a sudden, painful shutting down of the mechanisms controlling intraocular fluid pressure. In “secondary” glaucoma, factors such as trauma, certain drugs, infections, tumours or advanced cataracts cause an increase in the intraocular fluid pressure.
Glaucoma is the second leading cause of blindness worldwide. It is a heterogeneous group of disorders marked by damage to the structural or functional integrity of the optic nerve that causes characteristic atrophic changes. Over time, this may also lead to specific visual field defects. Damage can be arrested or diminished by adequate lowering of intraocular pressure (IOP). Yet, some debate still exists as to whether IOP should be included in the definition of glaucoma, as some subsets of patients can exhibit the characteristic optic nerve damage and visual field defects while having an IOP within the normal range. PRESSURES DO NOT DETERMINE IF YOU HAVE GLAUCOMA. You can have normal or low pressure and have glaucoma. It is thought up to 50% of people with glaucoma have normal tension glaucoma. Your eye doctor must examine your optic nerve head to diagnose glaucoma.
The generic term “glaucoma” refers to the entire group of glaucomatous disorders as a whole, because multiple subsets of glaucomatous disease exist. Glaucoma is not just a disease of IOP but rather a multifactorial optic neuropathy. A more precise term should be used to describe the glaucomatous disorder, if the specific diagnosis is known.