Glaucoma, the silent thief of sight as it is also known, is the second leading cause of blindness worldwide. In the early stages, the disease has no symptoms. People are usually not aware that they have glaucoma until serious vision loss has occurred.
Glaucoma causes progressive blindness to the eyes by damaging the optic nerve (a nerve in the eye which sends visual signals to the brain). This leads to loss of the peripheral (sides) visual field and progresses to blindness.
What are the types of glaucoma?
The aqueous humour is a clear fluid which flows continuously through the anterior chamber (a space in front of the eye) and helps to nourish the eye. It leaves the chamber at an angle where the cornea and iris meet. At this angle, it flows through a meshwork which acts like a drain, and leaves the eye.
The most common form of glaucoma is the primary open angle type. Here, the aqueous humour passes too slowly through the meshwork and so the pressure rises slowly over time. The only symptom is a gradual loss of vision.
Angle closure glaucoma, though less common, develops suddenly and usually causes eye pain or redness. Here, the pressure rises quickly because normal flow of aqueous humour within the eye is blocked. This happens when there is blockage of the junction where the iris and cornea meet.