The Mechanisms of Glaucoma
When the exit of aqueous humour from the eye is abnormally limited, the intraocular pressure is elevated.
The optic nerve in the back of the eye is fragile zone and can be deformed and damaged by elevated intraocular pressure. Subtle long-term elevation of the intraocular pressure (or sudden high elevation) can deform and crush the optic nerve fibers in the back of the eye. This causes a deficit in the field of vision or even the center of the vision. That is the basic cause of glaucoma.
There are different forms of glaucoma:
Open angle glaucoma
C’est la forme la plus fréquente de glaucome. Elle est liée à la fermeture progressive du filtre d’évacuation (trabeculum) du liquide intraoculaire. Le fait que ce phénomène soit progressif explique que le patient ne ressente pas l’augmentation lente de la pression oculaire,
Le glaucome par fermeture de l’angle (aigu ou chronique)
Open angle glaucoma
Open angle glaucoma is the most frequent form of glaucoma. It is normally caused by asymptomatic, elevated intraocular pressure with slow progressive damage to peripheral vision which is why the patient usually does not realise visual damage is occurring.
Narrow angle glaucoma (acute or chronic)
In acute glaucoma, the drainage of aqueous humour is acutely blocked by the iris moving. This is associated with pain, acute loss of vision, and red eye. It is an urgent condition.
Chronic narrow angle glaucoma is associated with progressive blockage of drainage of aqueous humour through the trabeculum from the eye by the root of the iris. The intraocular pressure rises. If this condition is not treated, it can lead to an acute glaucoma crisis or to gradual damage of the optic nerve.
Congenital: Congenital glaucoma is present on birth. Treatment is usually surgical.
Secondary glaucoma: Glaucoma can also occur following another eye disease, secondary to another condition, such as an infection, an inflammation, trauma, or intraocular surgery such as retinal detachment repair, corneal transplant, cataract surgery.