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Presenter lauds benefits of using VEP, PERG for early diagnosis
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ATLANTA – At a continuing education session here at SECO on Friday, Alberto Gonzalez-Garcia, MD, said visual-evoked potential and pattern electroretinogram are effective tools for diagnosing retinal dysfunction sooner in the disease process than with other technologies.
Gonzalez-Garcia, the research director for Diopsys, developer of electrophysiology testing equipment including VEP and PERG, said, "Even in the central area of the retina, if we stimulate with different contrast trying to isolate the function of the other symptoms, we have the ability to detect the dysfunction of the retina earlier."
In his presentation, Gonzalez-Garcia reviewed the basics of both tests.
“Visual-evoked potential is the electrical activity of the brain resulting from visual stimulation. So we need to stimulate to obtain a response,” Gonzalez-Garcia explained. “If you are getting information from the eye, you need to stimulate that structure. The pattern ERG is also the electrical activity of the ganglion cells resulting from that stimulation.”
Gonzalez-Garcia said that while previous versions of the tests posed limitations such as a testing time of 45 minutes and the requirement of highly trained operators, newer versions are more convenient for practitioners.
Now, tests can be performed in 1 minute without highly trained operators, he said.
According to Gonzalez-Garcia, the technology is installed in about 1,200 offices.
VEP can be used for glaucoma, multiple sclerosis, ischemic optic neuropathy, traumatic brain injuries, amblyopia and other neuropathies, Gonzalez-Garcia said, while PERG can be used for glaucoma and maculopathies.
He discussed how the tests can help practitioners treat patients earlier.
In a longitudinal study in patients with glaucoma conducted at the Bascom Palmer Institute, it was shown that pattern ERG detected dysfunction 8 years before it was picked up with optical coherence tomography.
"If we can detect dysfunction before we have a structural problem, that will give you the ability to resolve the dysfunction," he concluded. – by Chelsea Frajerman
Disclosure: Gonzalez-Garcia is the research director for Diopsys.