Glaucoma is a group of eye conditions in which the optic nerve becomes damaged, usually due to a rise in intra-ocular pressure (IOP).
If left untreated, this damage (neuropathy) can cause loss of field of vision – and ultimately blindness.
Types of glaucoma
A rare but serious developmental abnormality of the eye causing glaucoma.
There are several possible causes including inflammation, trauma, surgery and syndromes such as pigment dispersion and pseudo-exfoliation.These cause raised IOP and glaucoma.
Pigment dispersion syndrome (PDS) is when pigment is released from the iris into the anterior chamber (fluid filled chamber at the front of the eye) which may then lead to a blockage of the drainage canals, a rise in eye pressure and damage to the optic nerve. This is known as pigment dispersion glaucoma.
Pseudo-exfoliation (PXF) is a rare condition caused by a build-up of abnormal protein which may block the outflow of fluid, cause raised eye pressure and may lead to optic nerve damage.
Primary open-angle glaucoma (POAG)
This is the most common form of glaucoma. Ten percent of over 75 year olds will have some form of POAG. The drainage angle of the eye is damaged, preventing the correct amount of fluid from draining away, leading to a raised IOP and damage the optic nerve.
It tends to run in families, with raised intra-ocular pressure the biggest risk factor in POAG. However, glaucoma can occur in patients with “normal” intra-ocular pressure (normal tension glaucoma).
Other risk factors include age, corneal thickness, ethnicity, myopia (shortsightedness) and diabetes.
Primary angle-closure glaucoma (PACG)
This is a much rarer condition in the UK, which occurs when the drainage angle between the iris and cornea, through which fluid passes is unusually narrow and can becomes close off. When this occurs, the inner eye pressure rises sharply, causing pain, nausea, blurred vision and redness in the eye.
It also tends to run in families, with hyperopic (long-sighted) eyes more at risk.
Women are three times more likely to suffer from closed angle attacks.
Symptoms of glaucoma
It is estimated that over 11.2 million people across the world will be completely blind by 2020, as a result of glaucoma.
So understanding the symptoms has never been more important for your eye health.
Symptoms of open-angle glaucoma
There are generally no symptoms or early signs of open-angle glaucoma which is why it is known as the “silent thief of sight”.
If untreated, open-angle glaucoma can lead to sight loss so it is critical to see an eye doctor for regular examinations. If this is in one eye only, it may go unnoticed until vision is profoundly affected.
This is the most common type of glaucoma, and if you are diabetic or have cardiovascular disease you are at an increased risk of developing the eye disease.
The risk of developing open-angle glaucoma also increases with age. If you have a family history of glaucoma and are over the age of 40, you should see an eye doctor every one to two years to monitor your eye health.
Symptoms of angle-closure glaucoma
Symptoms to look out for in angle-closure glaucoma include eye and head pain, the appearance of rainbow colour circles in bright lights, and blurry vision. The pain can cause nausea and vomiting and can even lead to sudden sight loss.
These symptoms can develop quickly and are immediately noticeable. If untreated, you are at risk of suffering from repeated closed angle attacks and/or a sustained raised intraocular pressure (IOP). This can lead to damage to the optic nerve, known as primary angle-closure glaucoma (PACG).
It is crucial that you monitor the condition of your eyes by having regular eye examinations.