Glaucoma causes damage to the optic nerve. The optic nerve carries the images we see to the brain. The optic nerve is like an electric cable containing about 1.2 million wires. Glaucoma can damage nerve fibers, causing blind spots to develop.
What causes glaucoma?
Many people know that glaucoma has something to do with pressure inside the eye - the intraocular pressure (IOP).
Pressure builds up in the eye when the clear liquid called the aqueous humor, which normally flows in and out of the eye, is prevented from draining properly. This can happen in different ways, depending on the type of glaucoma. The resulting increase in pressure within the eye can damage the optic nerve.
Ophthalmologists used to think that high intraocular pressure was the main cause of optic nerve damage in glaucoma, however we now know that even people with "normal" IOP can experience vision loss from glaucoma - so-called "normal tension glaucoma".
Some people with high intraocular pressure never develop the optic nerve damage of glaucoma. (These people need to be followed carefully by an ophthalmologist, because they are considered "glaucoma suspects").
Elevated IOP is still considered a major risk factor for glaucoma, though, because studies have shown that the higher the IOP is, the more likely optic nerve damage is to occur.
Clinically, many people with glaucoma have no symptoms. Because the visual loss is very slow, they are often unaware of their decreasing field of vision. Glaucoma usually affects both eyeballs. If the eyeball pressure is high enough, the person may feel discomfort or pain in their eye(s). The eyes may become bloodshot during this period.
Risk factors for glaucoma are:
Old age (prevalence
increases rapidly in those >40 years old) Blood relative with
glaucoma Nearsightedness (myopia)
Diabetes High blood pressure
Most opticians give free glaucoma testing as a contribution to the eye care of the nation. If you are worried about glaucoma please e-mail me and I will arrange for a free glaucoma test.