Additional information about the GDx Nerve Fiber Analyzer
Unlike existing technologies, GDx provides a rapid, objective and accurate evaluation of the eye because it measures the site of glaucoma damage, not just a symptom of the disease (such as failing a visual field exam).
The GDx analyzer provides immediate answers ( less than 3 minutes for both eyes), and doesn't require dilation. The actual time spent in acquiring data (taking a snapshot of your eye) is less than 3/4 of a second.
Measurements are automatically compared to normative data for your age/sex/race. This data is specific not just to your eye as a whole, but is specific to each of the 4 quadrants of each eye.
The patented technology used by the GDx uses a near infra-red laser to double pass the retinal nerve fiber layer. It is then split into two parallel rays by the birefringent fibers of your eye. The two rays travel at different speeds and this difference (called retardation) directly correlates to the layer thickness. This is what is being measured.
During this incredibly fast laser measurement, 65,536 points are measured in a full 15 degree field. Actual measurements are available for each and every point. Only GDx can provide this measurement of the nerve fiber layer.
The printout of the exam provides your doctor with a detailed report of your retinal nerve fiber layer. It provides a color-coded thickness map along with key parameter to compare you with a normative database.
A neural network is used by the software to consider hundreds of parameters obtained when the image is acquired. It then assigns a number between 0 and 100. The higher the number, the higher the probability a patient has glaucoma.
The GDx has the ability to do serial analysis, which allows your doctor to track disease progression over time as exams are repeated. Because of this, treatments your doctor may prescribe may be monitored for their effectiveness.
The GDx is the only exam to directly measure the tissue affected by glaucoma.