Glaucoma is a common eye condition, affecting 1% of the general population and 2% of those over the age of 40 years in the United Kingdom. Glaucoma usually arises when the pressure in the eyes is too high, causing damage to the optic nerves. The eye pressure rises because there is a reduction in the normal flow of fluid out of the eye. Glaucoma often runs in families. People who have relatives affected by glaucoma are at a slightly higher risk of developing glaucoma in their lifetime, and for these people, testing for glaucoma therefore regularly is advisable.
Early Detection, Diagnosis and Monitoring
Unfortunately, many people who develop glaucoma have virtually no symptoms. If the condition is not diagnosed in its early stages significant visual loss can occur. Regular testing for glaucoma is therefore essential to prevent this.
Glaucoma testing or screening is recommended for people over the age of 40 years, and from a younger age if there is a family history of glaucoma. Seeing a glaucoma specialist is the best way of ensuring that glaucoma is detected before any irreversible damage to vision occurs.
In order to determine if there are any signs of glaucoma, important tests are required such as a visual field test to check peripheral (outer) vision, and state of the art imaging of the optic discs (OCT- Optical Coherence Tomography) to detect the very earliest signs of high pressure-related optic nerve damage.
For all people with either glaucoma or increased eye pressure (ocular hypertension), regular, long-term check-ups are essential. This is because, usually, people cannot tell if the eye pressures are abnormally high or if subtle loss of vision is occurring. It is therefore essential to see a glaucoma specialist to regularly check the eye pressures, assess the optic discs, and check the visual fields looking for evidence of visual field defects. Usually, once the diagnosis is made and treatment has been shown to control the eye pressures, check-ups are every 6 to 12 months are recommended, depending on the severity of the glaucoma.
For many patients with glaucoma all that is needed to prevent glaucoma progression are daily eye-drops and regular monitoring by a glaucoma specialist. Eye-drops are the mainstay of treatment for glaucoma and are highly effective for the vast majority of glaucoma patients. There are several classes of eye-drops. Initially a prostaglandin analogue is typically prescribed which is highly effective in lowering the eye pressure. However, should this prove to be ineffective, other drops such as β-blockers (e.g. timolol) or carbonic anhydrase inhibitors (e.g. dorzolamide) may be prescribed, often in conjunction with each other.
Laser and Surgery for Glaucoma
For a very small number of people with glaucoma, eye-drops are not enough to maintain normal eye pressures and prevent damage to their vision. Even in the late stages of glaucoma, many people will not notice worsening of their eyesight. If progressive optic nerve damage and peripheral loss of vision are detected, despite using eye-drops, either Laser treatment or surgery to lower the eye pressure may be recommended.
Some types of glaucoma are especially responsive to certain types of Laser treatment. Examples include Laser trabeculoplasty for open angle glaucoma, and YAG Laser iridotomy and Argon Laser iridoplasty for narrow angle glaucoma. These procedures are essentially pain-free, requiring no specific anaesthesia and are easily performed as an outpatient.
Surgery – Trabeculectomy / Glaucoma drainage implants
In a minority of cases where eye-drops do not adequately control the eye pressures, surgery may be the only way to control glaucoma and safeguard eyesight. A procedure called trabeculectomy is the gold standard surgical treatment and has the best chance of successfully lowering the eye pressure to safe levels.
Very occasionally, trabeculectomy is ineffective in controlling complex glaucoma, and other more advanced surgical procedures may be recommended, such as glaucoma drainage implant surgery.