pattern electroretinogram, visual evoked potential

Cutting Edge Technology Pattern ElectroRetinogram Measures Retinal Function

The Diopsys® Pattern Electroretinogram gives our eye doctors an objective assessment of retinal function. Incorporating the most advanced technology available in caring for our patients is important to the care we deliver at Total Eye Care.  The Pattern ERG (PERG) measures the signal strength of the retinal information being sent to the optic nerve. This is in contrast to the Visual Evoked Potential (VEP) which evaluates optic nerve function.

Early Detection of Glaucoma

A recent study from the Bascom Palmer Eye Hospital showed that a 10% decrease in the Pattern Electroretinogram signal strength can be detected up to 8 years earlier than a 10% loss of nerve fibers detected by a scanning laser ophthalmoscope or optical coherence tomographer. What does this mean? It means the PERG allows us to detect glaucomatous nerve fiber loss much earlier allowing for earlier diagnosis and treatment of glaucoma.

The traditional gold standard for glaucoma diagnosis and treatment has been the threshold visual field. That standard has shifted over the last 5-10 years with the use of the OCT scanning laser ophthalmoscope. Patients report preferring electrodiagnostic testing, such as the PERG and the VEP,
to the visual field. We now have a host of options available to us in the diagnosis and treatment of glaucoma.

How Does the Pattern ElectroRetinogram Work?

The pattern ERG measures retinal nerve function. It does this by measuring the strength of the signal emanating from the retinal nerve fibers. Of secondary importance is the lag of the signal or how long it takes the retinal signal to get to the brain. Low signal strength or a delayed signal can indicate abnormal retinal nerve function.

What is Involved in Getting a Pattern ElectroRetinogram?

The electroretinogram is an easy, patient-friendly test. The technician will connect a sensor below your eyelid and on two other places of the head. After that, all you have to do to get good results is to look at the center of the computer screen while it presents a series of checkerboard patterns. It is very important that you only look at the computer monitor. Once the sensors are in place the test takes only a couple of minutes. That’s all there is to it.

Your doctor will go over the results with you, compare the PERG with other testing, and discuss how this will impact your treatment plan. The progression of conditions affecting the retinal and optic nerve fibers can be monitored over time by repeating the pattern electroretinogram and comparing the data to prior tests.

Conditions Monitored with the Pattern ElectroRetinogram

The Pattern ERG is helpful in the diagnosis and treatment of a wide variety of conditions such as;