GLAUCOMA

Glaucoma is a group of diseases that can lead to damage to the eyes optic nerve. The optic nerve is a bundle of more than 1 million nerve fibres and it connects the light-sensitive layer of tissue at the back of the eye (retina), with the brain. A healthy optic nerve is vital for good eyesight, any damage to it can lead to blindness.

What causes Glaucoma?
The eye is filled with a watery liquid known as aqueous humour. The aqueous humour which fills the front part of the eye is produced by the ciliary body which sits just behind the iris. A series of sieve like channels allow this fluid to be drained back into the bloodstream. In a healthy eye the amount of fluid produced is balanced out by the amount that is drained away, resulting in a constant pressure within the eye.

A person suffering from Glaucoma can experience raised pressure inside the eye which causes optic nerve damage. The rise in pressure normally occurs because the aqueous humour does not drain away properly due to a dysfunctional drainage system. Poor blood supply and a weak optic nerve have also been sited as causes of Glaucoma. People at risk from Glaucoma include:

	People who have suffered an eye injury or had eye surgery
	Anyone over the age of 60
	Diabetics, Heart Disease or other chronic condition patients
	African-Americans
	Those with a family history of Glaucoma

What are the symptoms?
Open-angle glaucoma is the most common type and has no symptoms in the beginning. This is why it has been referred to as the ‘silent thief’ of sight as the person with glaucoma is usually unaware of it until serious loss of vision has occurred. There is no pain and vision stays clear, though people may miss objects to the side or corner of their eye.

If urgent treatment is not sought, side vision may disappear completely and the sufferer may feel as though they are looking through a tunnel. Over time this central vision may also reduce and render the person blind. If any of the following symptoms become evident in your sight, seek immediate advice from your GP:

	Blurred or Loss of vision
	Frequent change of glasses
	Headaches or pain in the eyes
	Seeing halos around lights

What are the different types of Glaucoma?
The different types of Glaucoma are as follows:

• Open Angle Glaucoma – This is the most common type and occurs when the eye’s internal drainage system becomes inefficient or blocked over time, this then leads to a rise in aqueous humour fluid which in turn increases the pressure within the eye. Usually happens slowly without major symptoms and gradually affects vision by which time the optic nerve may have been damaged. Hence regular screening for those aged over 40 is advised.

• Closed Angle Glaucoma – Also known as Acute Glaucoma this condition is less common. Involves the complete and sudden blockage of the drainage system within the eye and can cause permanent blindness if not treated urgently. The affected eye can become very painful and red. Immediate treatment to reduce pressure in the eye is required along with treating the other eye due to its chances of also developing the same condition.∑ Normal Tension Glaucoma - Attributed to the poor rate of blood flow travelling to the optic nerve in the eye which can results in vision loss. Interestingly this can occur even when the pressure level within the eye is normal.

• Secondary Glaucoma – A rare type of Glaucoma that is possibly caused by previous eye operations, diseases or past injuries.

• Congenital Glaucoma – Another uncommon Glaucoma which is caused by a physical abnormality of the eye usually present at birth.

Glaucoma can be treated and controlled though not completely cured. Early detection and diagnosis by testing pressure in the eye via a painless tonometry test, are important if permanent damage to sight is to be avoided. Depending on the type of Glaucoma the treatment can include medicine, conventional surgery or laser surgery.