January is Glaucoma Awareness Month
Why is glaucoma called the “thief of eyesight”?
Glaucoma is a disease that involves damage to the optic nerve at the back of the eye. The optic nerve contains about a million neurons that connect the retina to the brain.
The reason glaucoma is called the thief of eyesight is that at first there are often no symptoms. In the case of “open-angle” glaucoma, the more common type of glaucoma, damage can be occurring for a long time. Eventually, as more damage to the nerve occurs, vision loss will be noticed.
The risk of glaucoma increases with eye pressure. There are usually no symptoms when eye pressures are moderately elevated. It is also possible to have normal pressures and still be developing glaucoma, known as normal-tension glaucoma.
A number of neurons are damaged in early stages of the disease, however there is redundancy in the system. Part of the visual field covered by one neuron may also be covered by another. It is also difficult to notice the very gradual losses of sensitivity in one’s field of vision. One is usually not aware that the disease progressing.
“Narrow-angle” glaucoma can be different. If the angle closes the eye pressure can become very high very quickly. This typically produces symptoms such as eye pain, redness, blurred vision and nausea – an eye emergency. With very high eye pressure damage to the optic nerve will occur more quickly.
To understand open and narrow angle glaucoma as well as different treatments this 6 minute video will provide a lot of information.
Measuring the eye pressure is important but many other pieces of information help to assess glaucoma risk including:
- Age, family, medical and eye history,
- Refraction: Nearsighted or farsighted
- Appearance of the optic nerve at the back of the eye
- Corneal thickness
- Anterior chamber angle assessment
- Retinal nerve fibre layer thickness
- Visual field assessment
Only some patients at risk will actually go on to develop glaucoma. Careful monitoring will help to identify if and when treatment is needed.
Go to Glaucoma – Canadian Association of Optometrists for more information on Glaucoma including brochures in English, French, Ojibwe and Cree.
Find out about your risk of glaucoma – book a routine eye examination with your Thunder Bay Eye Care optometrist.