What is glaucoma?
Glaucoma is a condition in which the optic nerve is damaged, either by high pressure in the eye or by poor blood supply to the nerve. This results in slowly progressive loss of peripheral vision. When advanced, patients may develop tunnel vision and finally lose central vision.

It is caused by a number of diseases, the most common of which is primary open angle glaucoma. This is present in 1% of 60 year olds, 3% of 70 year olds and 5% of 80 year olds.

Symptoms of glaucoma
Apart from patients with acute angle closure glaucoma, patients presenting with glaucoma rarely describe any symptoms. Most patients have no idea that their eye pressures are elevated and only very rarely will a patient have noted a problem with his or her peripheral vision. This explains why regular check-ups with your optician are so important. This also explains why only 50% of patients with glaucoma have been diagnosed with the condition. Many patients with glaucoma do not realise they have it.

Detection of glaucoma
Glaucoma can only be picked up by an optician or ophthalmologist. Unfortunately, the diagnosis is not always straightforward as, at least in the early stages of this slowly progressive disease, there is overlap in the clinical features with the normal population.

A finding of raised pressure, does not, in itself, mean glaucoma, because only a proportion of patients with raised pressure go on to develop damage to the optic nerve and peripheral vision changes. Such patients are said to have ocular hypertension.

Because the damage to the optic nerve is irreversible, we can only preserve vision the vision that remains, so early detection is vital.