The definition of glaucoma has changed drastically since its introduction around the time of Hippocrates (approximately 400 BC). The word glaucoma came from ancient Greek, meaning clouded or blue-green hue, most likely describing a patient having corneal swelling or rapid evolution of a cataract precipitated by chronic elevated pressure. Over the years, extensive refinement of the concept of glaucoma has continued, accelerating, especially in the last 100 years, to the present date.
Currently, glaucoma is defined as a disturbance of the structural or functional integrity of the optic nerve that causes a slow, painless, progressively characteristic damage to the optic nerve, which may also lead to specific visual field (peripheral vision) defects over time. Most commonly the patient is unaware of the vision loss until the visual field is significantly advanced. The progression can usually be arrested or diminished by the adequate lowering of intraocular pressure (IOP). While elevated IOP was felt to be a characteristic in the past, some patients can exhibit the characteristic optic nerve damage and visual field defects while having an IOP within the normal range.
Glaucoma is a major worldwide health concern because of its usually silent, progressive nature, and because it is one of the leading preventable causes of blindness in the world. With appropriate screening and treatment, glaucoma usually can be identified and its progress arrested before significant effects on vision occur. Early treatment and management of glaucoma is essential in preventing long-term vision loss. The key to successful management is early detection and regular follow-up examinations.