GLAUCOMA  (modified from Canadian Ophthalmic Society Website)
The optic nerve is the "wire" that sends visual information from the eye to the brain.  Glaucoma is an optic nerve disease that is in part due to the eyeball pressure (intraocular pressure) being higher than what the patient?s eye can withstand.  Glaucoma affects as many as 1/100 older Canadians. It is one of the most common causes of blindness. Although predominantly associated with increased age, glaucoma may develop at any age, even in infancy.  RISK FACTORS for glaucoma include age >50, heredity, myopia/hyperopia, disease such as early heart attack & stroke, and raised eyeball pressure or intraocular pressure (IOP).  (Abnormalities of the small blood vessels that nourish the optic nerve may also cause glaucoma, but at present we do not know how to fix this.)
Raised IOP is found in most types of glaucoma and is the main target for control of the disease. The eyeball continually produces fluid (aqueous) to help with its metabolism.  When there is a balance between fluid pumped into the eye and the amount that escapes from the eye, the IOP is normal. Raised IOP occurs when fluid outflow is obstructed. Visual loss in glaucoma is thought to be caused by raised IOP and other influences on the optic nerve, located at the back of the eye. The gradual loss of nerve function causes initially unnoticed, painless loss of peripheral (side) vision.  Later the detail (central) vision is affected.
Open-angle glaucoma  Open-angle glaucoma is the most common form of glaucoma. Patients rarely notice any symptoms until the disease is very advanced; it is a "silent blinding disease". Those affected can drive, read and perform most tasks because the visual loss usually is not a black cloud or a blurring of the vision. Because this loss is permanent and cannot be reversed by treatment, early detection and treatment are necessary to preserve remaining vision.  Tests for glaucoma are painless and take little time. The IOP is measured with a tonometer (blue light), and the optic nerve is viewed through the pupil with an ophthalmoscope. Field tests (push button tests) and more elaborate tests may be required.
Treatment is begun with eye drops, which decrease the IOP. It may be necessary to change from one type of drop to another. This lifelong disease must be constantly monitored to ensure the best treatment. All the medications are short acting, so it is important that patients follow the eye drop schedule faithfully.  Although the eye drops may be ineffective in some patients, sometimes they do not work because the patient cannot get the drops in the eye, or continually forgets to use the eye drops.  If control is not achieved with eye drops, a pill (diamox), and laser therapy, performed during an outpatient visit, may be required to improve fluid drainage. If this also fails to decrease the IOP, surgery may be advised.
Closed-angle glaucoma  Less frequent than open-angle glaucoma, it usually presents as the sudden onset of dull, aching pain over one eye associated with a change in vision, and nausea and vomiting. These changes may occur as blurring and haloes (rainbows) around lights. This usually happens very quickly (within a half-hour) and is an emergency! The aim of treatment is to decrease the IOP before permanent damage occurs. A small opening in the eye with either laser or surgery (iridotomy or iridectomy) is then made to prevent another attack.  Laser is performed in the other eye also, since it will usually follow suit.
Risk factors for glaucoma  Be aware of the possibility of glaucoma, particularly if you have any of the risk factors (age>50, family history of glaucoma, myopia/hyperopia, general disease such as early heart attack and stroke, and raised intraocular pressure). Some drugs, such as cortisone (steroid) drops, can cause glaucoma. As well, any visual disturbance that cannot be corrected by glasses may be a sign of glaucoma.  In Canada, only medical doctors (ophthalmologists) can prescribe medications, and perform laser/surgery for glaucoma.
The MYTHS   All of the following are FALSE:  1) If I can see, I don't have glaucoma.            2)  Glaucoma is caused by pressure or anxiety.  3)  Glaucoma is caused by poor nutrition or lack of vitamins.  4)Glaucoma is a form of cancer.  5) Using your eyes can make glaucoma worse.