Firstly, a referral to the glaucoma clinic does not mean that you definitely have glaucoma. It generally means that the optician has spotted some changes that are more common in people with glaucoma. You won't know whether you have the condition until the hospital eye service has run further tests on you and you might even need to be monitored for years before they decide whether you have it.
Primary open-angle glaucoma (POAG) occurs when neurons (nerve cells) in the eye are damaged either by raised pressure inside the eye or by being over-sensitive to a normal eye pressure. Untreated POAG (primary open-angle glaucoma) generally progresses very slowly but over the years can cause some degree of vision loss e.g. tunnel vision. Various effective treatments are available, including eye drops which help prevent any deterioration in vision. However, the treatments will not improve vision that has already been lost. The likelihood of glaucoma increases with age and people often don't notice any loss of vision until the disease is quite advanced which is why an optician check at least every 2 years after the age of 40 is recommended.
At the eye clinic appointment, they will generally give you a range of tests which may include:-
- measuring your visual acuity in each eye (by getting you to read an eye chart)
- a field test (you click a button every time yousee a faint light whilst staring straight ahead)
- a scan of the optic nerve (just by looking into a 'camera' and trying not to blink)
- an examination of your optic nerve with a slit lamp
- measuring the thickness of your cornea
- measuring the pressures within each eye
There is another type of glaucoma called angle-closure glaucoma which can come on very rapidly and causes severe eye pain, red eye and the appearance of haloes around lights. This is a different disease and would require a visit to eye casualty.
More information here:-
http://www.nhs.uk/Conditions/Glaucoma/Pages/Diagnosis.aspx
