Chronic open-angle glaucoma:

This is the most common type of glaucoma. The drainage angle, where the fluids in the eye drain, is open but working less efficiently. The inability to drain causes pressure within the eye to rise, which results in a gradual loss of peripheral vision. This can be likened to an air filter, which gathers dust over time & eventually becomes too laden with dust to work properly.

Angle-closure glaucoma:

This type of glaucoma occurs when the drainage angle is completely blocked, often by the iris. This prevents any fluid to drain from the eye & causes the pressure within the eye to suddenly rise. Common symptoms that are caused by this extreme rise in pressure include blurred vision, headaches, severe eye pain as well as the appearance of halos around lights.

Chronic angle-closure glaucoma:

This is painless and more gradual closing of the drainage angle, which occurs most frequently in people of African or Asian descent.

Secondary Glaucoma:

This type of glaucoma progresses very much like chronic open-angle glaucoma. It occurs when scar tissue blocks the drainage angle. The first symptom is loss of peripheral vision.

Congenital Glaucoma:

This is a birth defect, which affects the drainage angle. To prevent blindness, this condition must be treated shortly after birth. Symptoms include enlarged eyes, a cloudy cornea, light sensitivity, and excessive tearing.