What is glaucoma?

 Glaucoma is a disease of the optic nerve — the part of the eye that carries the images we see to the brain. The optic nerve is made up of many nerve fibres, like an electric cable containing numerous wires. When damage to the optic nerve fibres occurs, blind spots develop.

  These blind spots usually go undetected until the optic nerve is significantly damaged. If the entire nerve is destroyed, blindness results. Early detection and treatment by your ophthalmologist are the keys to preventing optic nerve damage and blindness from glaucoma.

Glaucoma is a leading cause of blindness , especially for older people. But loss of sight from glaucoma can often be prevented with early treatment. What causes glaucoma? Clear liquid called aqueous humor circulates inside the front portion of the eye.

 To maintain a healthy level of pressure within the eye, a small amount of this fluid is produced constantly while an equal amount flows out of the eye through a microscopic drainage system. (This liquid is not part of the tears on the outer surface of the eye.)

Because the eye is a closed structure, if the drainage area for the aqueous humor — called the drainage angle — is blocked, the excess fluid cannot flow out of the eye. Fluid pressure within the eye increases, pushing against the optic nerve and causing damage. If the drainage angle is blocked, excess fluid cannot flow out of the eye, causing the fluid pressure to increase. Drainage angle Cornea Iris

Who is at risk for glaucoma?

Your ophthalmologist considers many kinds of information to determine your risk for developing the disease. The most important risk factors include:

• Age

• Elevated eye pressure

• Family history of glaucoma

• African or Hispanic ancestry;

• Farsightedness or nearsightedness

• Past eye injuries

• Thinner central corneal thickness;

• Systemic health problems, including diabetes, migraine headaches and poor circulation

 Pre-existing thinning of the optic nerve. Your ophthalmologist will weigh all of these factors before deciding whether you need treatment for glaucoma, or whether you should be monitored closely as a potential glaucoma patient. This means your risk of developing glaucoma is higher than normal, and you need to have regular examinations to detect the early signs of damage to the optic nerve.

How is glaucoma detected?

Regular eye examinations by your ophthalmologist are the best way to detect glaucoma. A glaucoma screening that checks only the pressure of the eye is not sufficient to determine if you have glaucoma. The only sure way to detect glaucoma is to have a complete eye examination. During your glaucoma evaluation, your ophthalmologist will:

•  Measure your intraocular pressure (tonometry)

•  Inspect the drainage angle of your eye (gonioscopy)

•  Evaluate whether or not there is any optic nerve damage (ophthalmoscopy)

•  Test the peripheral vision of each eye (visual field testing, or perimetry).

• Photography of the optic nerve or other computerized imaging may be recommended.

Some of these tests may not be necessary for everyone. These tests may need to be repeated on a regular basis to monitor any changes in your condition.

Monitoring glaucoma is like sailing a large ship. Things happen slowly but are difficult to reverse. The only way to steer the ship is by lowering the intra-ocular pressure with various treatments to achieve a target pressure: our compass bearing. The only way to know this compass bearing is to check our course and direction, by monitoring the pace and extent of glaucoma damage.

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