What is Glaucoma?
It is estimated that three million Americans have glaucoma, but only about half of them know that they have glaucoma. Glaucoma is a leading cause of blindness for people over 60 years old.
Glaucoma is a disease that damages your eye's optic nerve. The disease begins with a decrease in side vision, and if left untreated, can affect central vision as well. It usually happens when fluid builds up in the front part of your eye. That extra fluid increases the pressure in your eye, damaging the optic nerve. Glaucoma can also occur with normal pressures.
Ocular Hypertension is a condition in which the fluid in the eye is slightly above the normal level. This condition is not related to blood pressure, but to the pressure that is within the eyeball itself. Ocular hypertension does not always lead to glaucoma, but sometimes will be treated to decrease future risk of damage to the eye and vision from glaucoma.
How is Glaucoma Tested?
Glaucoma is a slow disease and is diagnosed with multiple tests over a period of time. It is important to remember that early detection, prompt treatment, and regular monitoring can prevent severe vision loss from glaucoma.
These tests are performed at intervals that will be determined on an individual basis considering your condition and findings. The tests will consist of the following:
- Intraocular Pressure Test – This test, called tonometry, allows us to measure the pressure inside the eye. Eye pressure is usually highest in the morning hours, and it is for this reason that we schedule some of these visits early in the morning.
- Visual Field Evaluation – This is a very important test which accurately monitors your side vision. It is a computer generated test, which enables us to detect the earliest of changes in the sensitivity of your peripheral vision. Since the earliest signs of visual loss in glaucoma are often seen in the visual field examination, this test is vital in monitoring your condition.
- Pupillary Dilation – The most accurate view of the inside of your eye can only be obtained through dilated pupils. To perform this test, drops are instilled into your eye, which keeps your pupils open (or dilated) for several hours. This dilation allows us to use special lenses that give us a three dimensional view of your retina and optic nerve to closely monitor for early changes which may be associated with glaucoma.
- Retinal Photography – Special stereoscopic photographs are taken with a camera, which document the appearance of your optic nerve and retina. These photographs serve as a baseline so that any future changes in the appearance of your nerve will be easily detected.
- Scanning Laser Ophthalmoscopy – This in-office test uses a low-powered diagnostic LASER that scans and produces a digital topographic map of the optic nerve. This fast and objective test is more sensitive than photography and allows us to detect the earliest change in nerve damage.
- Pachymetry – This in-office test measures the thickness of the cornea. New studies have shown that patients with thin corneas are found to have a significantly greater risk for developing glaucoma than those with thick corneas.
- Gonioscopy – This test allows for a view of the drainage of fluid from the eye. In some cases pressure can be elevated if the fluid in the eye has either a blocked or narrow drainage passage.
- VEP/ERG – An objective test of the visual pathway. Sensors are used to test the signal strength that is transmitted from the retina of the eye to the occipital lobe of the brain.