The eye is separated into anterior and posterior chambers by the lens and by a muscle, called the ciliary muscle, which supports it. There is also a structure called the ciliary body which manufactures a fluid called aqueous humor that fills the anterior chamber. This needs to be continuously drained and, when glaucoma is present, this does not happen. This causes pressure in the eyeball to rise, thus causing problems with sight.

There are three major types of glaucoma and they are as follows:

1. Angle closure glaucoma

2. Open angle glaucoma, and

3. Narrow angle glaucoma

The angle is where the iris meets the cornea. It is also where the fluid drains from the eye.

In angle closure glaucoma, the angle gets blocked. Fluid continues to be made but is unable to drain. Because of this, the pressure in the eye builds up to a level which is harmful.

With open angle glaucoma, the angle stays open but fluid builds up when the structure at the back of the angle becomes blocked.

Narrow angle glaucoma is a condition where the iris and the lens touch, trapping fluid. The iris bulges forward, effectively closing off the drainage angle and causing acute glaucoma.

Other types of glaucoma include:

1. Congenital glaucoma

2. Pigmentary glaucoma, and

3. Secondary glaucoma

Congenital glaucoma is rare and affects infants. These children are normally diagnosed by the age of one and are usually born with a defect in the drainage system of the eye.

Pigmentary glaucoma is also rare and happens when the pigment from the iris blocks the drainage system. The system is eventually damaged because of the inflammation caused by this condition.

Secondary glaucoma is normally caused by injury, infection, tumor, inflammation or and enlarged cataract. Any of these conditions can lead to secondary glaucoma.

Often, people with glaucoma don’t even realize that they have a problem as there are no obvious symptoms. The eyesight deteriorates so gradually that it is often unnoticed. The only real way of knowing that glaucoma is present is by a physical examination of the eye by a doctor or optometrist who may be able to see the problem by examining the eye with an ophthalmoscope.

An optometrist may notice if there are any areas of blindness in the part of the eye that is not used for detailed vision. This is the area affected with glaucoma initially. The area of the eye used for detailed vision is not affected at first and this is why people don’t notice the onset of glaucoma for some time.

Treatment usually consists of drops that are placed in the eye three or four times daily to improve the rate of fluid drainage. Sometimes, surgery may be required to create a new outlet for the fluid. Treatment does not always work and, in some cases, the person may become progressively blind no matter what treatment is used. Once sight has been lost, it cannot be restored, so early diagnosis and treatment are essential.