What is Glaucoma and what is the incidence?
- It is a condition in which the pressure inside the eye is sufficiently elevated ultimately to result in optic nerve damage and potential vision loss.
- It is the third leading cause of blindness behind cataract and macular degeneration.
- Two out of every 100 people over the age of 35 have their vision threatened by this disease. Yet when diagnosed early, blindness from glaucoma is almost always preventable.
- A pressure greater than 22 mm of mercury should be considered suspicious. If not frankly abnormal and the patient should be followed.
- A target or ideal pressure is the pressure at which no loss of vision or damage to the optic nerve occurs for the patient.
How does Glaucoma cause visual loss?
When we look at an object, the image is carried form the retina to the brain by the nerve of sight (Optic Nerve). This nerve is like an electric cable. It contains a million wires, each carrying a message to the brain, which join together to provide side vision, as well as sharp, central reading vision. Glaucoma can produce damage to these “wires”, causing blind spots in areas of vision to develop. People seldom notice these blind areas in the side vision until considerable optic nerve damage has occurred. If the entire nerve is destroyed, blindness results. Fortunately, this rarely occurs if glaucoma is diagnosed and treated before major damage has taken place.
Causes of Glaucoma
A clear transparent liquid called aqueous humor flows through the inner eye continuously. This inner flow can be compared to a sink with the faucet tryned on all the time. If the drainpipe gets clogged, water collects in the sink. If the drainage system of the eye gets similarly blocked, the fluid pressure within the inner eye is increased and can cause damage to the optic nerve.