Glaucoma is a disease of the eye which was vaguely described by the ancient Greeks. Today, we know that damage is caused
to the eye by just enough pressure inside the eye to cause that damage. The amount of pressure needed to cause glaucomatous
damage can be variable from person to person depending on internal and external factors. We say that normal eye pressure
ranges between 10 and 21 but there are some with glaucoma who have pressures of 12 and there are some who never show any
damage from glaucoma even with pressures of 30. Many people would be treated even without signs of damage if the pressure
of the eye were over 30.
Normally, aqueous humor is fluid produced by the ciliary body just posterior to the iris root (the iris is the colored
part of the eye which has the black pupil in the center) and flows under the iris, through the pupil, into the anterior
chamber (or front of the eye) and out through the trabecular meshwork (which makes a complete circle) and into the bloodstream.
There are many varieties of glaucoma:
- Congenital — seen in infants.
- Developmental — seen in children and adults due to abnormalities which are apparent and obstruct the aqueous outflow.
- Secondary — which is caused by inflammation, infection, cataract, systemic disease, steroids and trauma.
- Angle- closure — when the base of the iris blocks off the trabecular meshwork and the eye pressure suddenly rises causing
eye pain, decreased vision, redness of the eye and sometimes nausea and vomiting. This type of glaucoma is seen in less than
10% of all glaucoma and is treated with laser surgery.
- Open-angle — This is seen in 90% of the glaucomas and blockage is somewhere in the trabecular meshwork. The iris does not
close the trabecular meshwork as it does in angle-closure glaucoma. This glaucoma is treated with eye pressure lowering
medications, laser surgery as well as other types of surgery. Open-angle glaucoma is known as the “sneak thief of vision”
since it causes no pain or redness and the vision is lost from the periphery towards the central vision and then suddenly no vision.
Persons of African and Hispanic descent tend to have open-angle glaucoma more frequently. Glaucoma is seen in about 2-3% of
the population and more frequently after the age of 40. The older one is, the greater the possibility of getting glaucoma. Fifty
percent of people who have glaucoma are not aware that they have it.
The diagnosis of glaucoma is made on the basis of having two of four parameters:
- the eye pressure
- the amount of central cupping of the optic nerve head that is seen in the back of the eye
- the thickness of the nerve-fiber layer of the retina
- the visual fields
These tests are painless and take only a few to several minutes. The visual fields actually record if any
vision is lost. Photographs of the optic nerve heads or optic discs are also taken very easily with the latest digital cameras.
Monitoring glaucoma is usually every 3-4 months. Some people are monitored every 4-6 months because of high eye pressure but have
no eye damage and are not treated.
This photo shows changes in optic nerve cupping as glaucoma progresses. The nerve rim is composed of nerve fibers which are
gradually lost, resulting in an increase in the size and depth of the central cup or excavation of the nerve.
We use the Heidelberg retinal tomography, computerized visual field analysis, and instantaneous stereo optic nerve photos to asses
the health of the optic nerve and monitor the efficacy of treatment.
In most cases glaucoma can be controlled with eye drops. When this is not practical or effective we offer in-office laser
treatment; painless three minute laser trabeculoplasty, so that in most cases glaucoma surgery can be avoided. The doctors at
Physicians Eye Care and Laser Center have the expertise and latest technology to diagnose and treat all forms of glaucoma. The
key is early detection and treatment.
For more information on Glaucoma, visit the Glaucoma Research Foundation's website:
