Glaucoma, a group of eye diseases associated with the increase of pressure inside the eye causing optic nerve damage and loss of vision. There is no specific reason why the pressure builds inside the eye. There is no rule that the increased eye pressure will affect optic nerves. Also there is no guarantee that the optic nerve damage does not happen in a normal pressured eye. The different types of glaucoma known to the ophthalmic society are:

1. Primary Open Angle Glaucoma (POAG), the most common type of glaucoma, affects millions of people around the world is caused when the eye's drainage canal is clogged. The pressure inside your eye increases when the clear-watery fluid called aqueous humour is produced more than the drainage.

You may not recognise at the early stage of POAG. This is because this disease is chronic, affecting at a very slow pace. Rather you might start to think that the issues with your eyesight are because of the age.

Although this is common at the age of 40 and above, if you are diabetic, it's advisable to have your eyes tested for glaucoma from an earlier age. It is an inheritable disease and so you need to get it checked if you know you are from a family of members who have been diagnosed with glaucoma. There is a possibility of losing the eyesight if not diagnosed and treated on time.

2. Closed Angle Glaucoma, a very rare but serious type of glaucoma, happens because of the acute pressure build-up inside the eye. You can easily recognise this from the acute pain in your eyes, head-ache and vomitting sense. If detected, then you need to be treated immediately to avoid the possible permanent loss of vision. There is every possibility of the second eye also to get the same condition if one eye is affected and so normally the surgeon will treat both your eyes. If treated on time, there is a possibility of permanent recovery of your vision.

3. Normal Tension Glaucoma where your optic nerves are affected even though the pressure inside the eye is normal. There is no known reason why this condition occurs. Normally happens in a family where the members of the family have irregular heart rhythm.

4. Congenital Glaucoma occurs at birth. Must be detected and treated at the early stage itself to prevent the loss of vision. Normally this will be detected before the child becomes 1, but in some cases it will not be detected before the child turns 3 or 4.

5. Secondary Glaucoma occurs as a result of external influences like injury, tumour and diabetes. Secondary glaucoma includes

a. Pseudoexfoliative Glaucoma, an open glaucoma, caused by the blockage of the drainage system by the flakes peeled from the outer layer of the lens.

b. Pigmentary Glaucoma, caused by the pigment granules from the back of the iris mixing with the aqueous humour and blocking the drainage system.

c. Traumatic Glaucoma, caused by excessing rubbing of the eye as a result of an injury, pollution or chemicals.

d. Neovascular Glaucoma, caused by the unusual formation of new blood vessels blocking the drainage system. This is generally caused by diabetes and very difficult to treat as this involves blood vessels.

e. Irido Corneal Endothelial Syndrome, a very rare condition caused by the growth of the cells behind the cornea spreading over the drainage system and across the surface of the iris. This will affect the optic nerve. This cannot be treated by laser procedures.

The treatment varies depending on whether you have open glaucoma or closure glaucoma.