Glaucoma is a common eye condition affecting the optic nerve, which transmits vision from the eye to the brain. Each optic nerve contains more than a million nerve fibres, and these appear to be most vulnerable just where they leave the back of the eye. In untreated glaucoma, these fibres gradually die off, resulting in blurred or blank patches in the field of vision.
There are many different types of glaucoma. Sometimes it results from other eye disease or an eye injury. However, the commonest sort, called primary open angle glaucoma, usually starts in a previously healthy eye.
Primary open angle glaucoma becomes commoner with age, is painless, and doesn't cause other symptoms such as redness, watering etc. Like other types of glaucoma, it is often caused by raised pressure inside the eye, but in some cases can occur even with a normal pressure. Usually a patient can only tell they have it when significant damage has already been done. Unfortunately, there is no treatment which can undo the damage. It is therefore very important to detect glaucoma early, and optometrists are trained to do this as part of an eye check.
Treatment can slow or stop further progression of glaucoma. All current treatments work by lowering the pressure inside the eye, and for most patients, this will mean lifelong eyedrops, administered usually once or twice a day, depending on the type of drop. Where eyedrops are insufficient, surgery can also be carried out to lower the pressure in the eye.
We don't know why people get primary open angle glaucoma, but an important clue comes from genetic studies: it is well known that this type of glaucoma tends to run in families, and is much more likely if a parent or sibling has glaucoma. It seems that particular genes underly this condition, but only some of these genes, affecting a small proportion of glaucoma sufferers, have so far been identified. Further genetic research holds out the promise of leading us to the actual cause of this disease, enabling new and better treatments to be devised, and our department is actively engaged in this work.
Glaucoma is one of the world’s leading causes of blindness and affects about one person in every 50 over the age of 40. It damages the optic nerve and causes irreversible loss of vision. It is currently treated by lowering pressure within the eye by taking drops or with surgery – but this is not effective in all patients and those who are diagnosed often do not experience symptoms until their sight has already deteriorated.
A generous philanthropic donation recently made to Gift of Sight has been given to support a project to study the development of protocols for interpretation of sequencing data from ophthalmic genetic studies using samples given by local patients who have primary open angle glaucoma (POAG). This work is being led by Professor Sarah Ennis, Professor of Genomics at the University of Southampton.
Advances in sequencing technology have the potential to effect a real step change in the approach to medical genetic research and clinical diagnostics. Prompt identification of a faulty gene, or discovery of a new one, can assist in supporting the choice of treatment which will most benefit a patient, help us to ascertain links with other types of eye diseases and possibly lead to patients becoming involved in our academic research studies.