At first there are no symptoms


In its early stages, glaucoma — a deterioration of the optic nerve, which first affects peripheral vision — often has no symptoms. “That's why the disease is known as 'the silent thief of sight',” says Professor Keith Martin, President of the World Glaucoma Association. “Vision can become slightly blurry at the periphery, but this might not be noticed until central vision is affected. By then it's often too late to reverse the damage.”

If you are of Afro-Caribbean origin, or very shortsighted, you should be tested more often.

Early diagnosis is vital because treatment is available that can slow the progress of the disease. An optician will look at your optic nerve, measure your visual field and test the pressure within your eyes. It's sensible for people under 40 to have an eye examination every five years; although if you have a family history of glaucoma, or are of Afro-Caribbean origin, or very shortsighted, then your risk is increased so you should be tested more often. As the risk of glaucoma increases with age, those over 40 should also have more frequent eye examinations.


Eye drops, laser or surgery


Glaucoma patients can present with increased pressure inside the eyes, known as intraocular pressure, or IOP. To treat the disease effectively, it's important to lower pressure, which can be done using eye drops, laser treatment or surgery.

“Controlling the pressure in your eyes over the course of 24 hours reduces the risk of the disease getting worse,” says Martin. “The problem is, most studies show that only half the people who are prescribed treatment actually use it. They may take eye drops for a while but then either forget or give up. But if you have been prescribed eye drops, you must use them every day.”

Once-a-day eye drops are preferred.

Anything that can be done to make treatment less burdensome for the patient should be welcomed. “That might mean developing better tolerated eye drops or simply making eye drop bottles easier to open,” says Martin. The more eye drops patients are given the less likely they are to use them, which is one reason why eye drops that only need to be used once a day rather than two to four times a day have been an important advance.

In the last few years, a range of fluid-draining devices have been developed that can be implanted in the eye via minimally invasive surgery. “These devices are designed to lower IOP and reduce the need for eye drops,” says Martin. “Unfortunately, we don't know — yet — how they will work over the long-term; there is still more research to be done in this area."

“However, we now understand more about the pathology of the disease and this is opening up the possibility of treating glaucoma with gene therapy and stem cell therapy. We're starting to learn how to restore function to the injured optic nerve. In future there is the prospect that we may be able to improve the vision of glaucoma patients, as well as being able to slow the decline of the disease.”