Glaucoma is one of the leading causes of blindness in Canada. Glaucoma is a group of eye diseases which lead to progressive degeneration of the optic nerve. This in turn can lead to loss of nerve tissue that results in gradual irreversible vision loss and potential blindness if not detected and treated early.
The most common form of glaucoma is primary open angle glaucoma. This form is associated with elevated pressure caused by a backup of fluid in the eye.
The precise cause is unknown. Glaucoma is generally associated with increased fluid pressure in the eye, however, damage can also occur when eye pressure is normal; this is called normal pressure or normal tension glaucoma. Some theories point to an inadequate blood supply or poor perfusion.
It is possible that people with low-tension glaucoma may have an abnormally sensitive optic nerve or a reduced blood supply to the optic nerve caused by a condition such as atherosclerosis, a hardening of the arteries. In these circumstances even normal pressure on the optic nerve may be enough to cause damage.
If glaucoma is diagnosed at an early stage, treatment such as medication, eye drops and/or laser surgery can usually control or prevent further vision loss. If left untreated, some form of permanent vision loss is likely to occur.
The most common type of glaucoma is primary open-angle glaucoma. It develops painlessly and gradually and there are no early warning signs. Pressure in the eye slowly rises and unfortunately, the cornea adapts without swelling. If the cornea were to swell, which is usually a signal that something is wrong, there would be symptoms. Since this is not the case, this disease often goes undetected. It is painless, and the patient often does not realize that he or she is slowly losing vision until the later stages of the disease. However, by the time the vision is impaired, the damage is irreversible.
In other cases, glaucoma may appear suddenly and present warning signs and symptoms such as nausea, eye pain, red eyes, blurred vision and haloes around lights. This is called acute angle-closure glaucoma.
A comprehensive eye examination is often the only way to detect glaucoma. Your doctor of optometry will perform a simple and painless procedure called tonometry during your routine eye exam, which measures the internal pressure of your eye. Your optometrist will also look into your eye to observe the health of the optic nerve and retina, and inspect the drainage angle He or she may also use specialized equipment to measure your field of vision additional imaging machines to examine the optic nerve and retinal layers.
Treatment with daily eye drops and/or laser surgery is usually effective at maintaining your vision, but once vision is lost due to glaucoma, it cannot be restored. Patients with glaucoma must continue treatment for the rest of their lives. Since the disease can progress or change silently, compliance with treatment and eye examinations are essential. Treatment may need to be adjusted periodically.
Regular eye examinations with your optometrist are highly recommended to screen for and prevent glaucoma.
Content provided by the Canadian Association of Optometrists