Cutting Edge Technology Measures 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
Diopsys® Pattern Electroretinogram gives our eye doctors an objective
assessment of retinal function. 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
Early Detection of Glaucoma
A recent study from the Bascom Palmer Eye Hospital showed that a 10%
decrease in the Pattern ERG 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 ERG 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 Will I Have to Do?
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;
· Optic nerve disorders
· Nutritional and toxic eye disease
· Intracranial lesions
· Brain and central nervous system disorders
· Multiple sclerosis
· Neuromyelitis optica