It is a progressive optic neuropathy (a disease of the optic nerve) characterized by a specific pattern of damage to the optic nerve head and visual field. The damage of the visual system in Glaucoma is due to the death of retinal ganglion cells, the axons comprising the optic nerve and which drive visual impulses from the eye to the brain.
Glaucoma results from different conditions affecting the eye, most associated with increased intraocular pressure. An estimated 65 million people worldwide suffer from Glaucoma. It is important to note that elevated intraocular pressure Glaucoma is not synonymous, but it is the most important risk factor for the development and progression of glaucomatous damage.
The average intraocular pressure is between 10 and 20 millimeters of mercury. Greater or equal to 22 pressure, is considered as ocular hypertension.
When developing an ocular hypertensive damage to the optic nerve and visual field impairment, it is diagnosed as Glaucoma. Once a large number of nerve cells have died, blind or scotomas spots begin to appear in the visual field, initially in the periphery and subsequently with advanced compromised central vision. The resulting visual loss is irreversible because the nerve cells die without being able to be restored.
Several clinical and para-clinical tests are performed to diagnose the disease:
- Tonometry or intraocular pressure measurement.
- Examination of the optic nerve headed by ophthalmoscopy.
- Perimetry or visual field examination
- Gonioscopy or measurement of the angle
- Structural examination of the optic nerve such as tomography