Glaucoma is a group of diseases whose common characteristic is progressive atrophy of the optic nerve (neuropathy).
In the course of glaucoma one can experience total and irreversible loss of vision. According to the WHO glaucoma is the second leading cause of blindness and usually occurs in people aged over 60 years, but it can also attack people over 40 years of age. Glaucoma is not curable, and vision lost cannot be regained. With medication, laser treatment and/or surgery, it is possible to halt further loss of vision. Since open-angle glaucoma is a chronic condition, it must be monitored for life. Diagnosis is the first step to preserving your vision.
With open-angle glaucoma, the most common form, there maybe virtually no symptoms at the beginning of the illness. Usually, no pain is associated with increased eye pressure but sometimes eye discomfort can be present. Glaucoma symptoms result from the loss of individual nerve fiber bundles of optic nerve. Vision loss begins with peripheral or side vision. One may compensate for this loss unconsciously by turning a head to the side, and may not notice anything until significant vision is lost.
The best way to protect your sight from glaucoma is to get tested. If you have glaucoma, treatment can begin immediately.
The main types of glaucoma:

• open-angle glaucoma – in which the disturbed outflow due to the closing holes meshwork
• angle-closure glaucoma – in which contact or adhesion of the iris and cornea closes-way access to the trabecular meshwork