Pattern Electroretinography (PERG) Gives up to 8 Years of Advanced Warning
Incorporating the most advanced technology available in caring for our patients is important to the way we practice at Total Eye Care. The Diopsys® Pattern Electroretinograph is the newest addition to our suite of technology. The Pattern ERG (PERG) measures the signal strength of the retinal information being sent to the optic nerve. Studies show that a 10% decrease in this signal can be detected up to 8 years earlier than a 10% loss of nerve fibers detected by the scanning laser ophthalmoscope or optical coherence tomographer, thus allowing for a much earlier diagnosis and treatment.
Early detection and treatment of glaucoma is important due to the fact that nerve tissue cannot be regenerated. Twenty years ago, in the absence of a very high intra-ocular pressure, it was a common practice to wait until a visual field defect was present before initiating treatment. There is a significant amount of redundancy in the retinal nerve fibers, thus studies have shown that a patient must lose approximately 50% of the nerve fibers serving a given section before the loss of nerve fibers result in a detectable visual field defect. The scanning laser ophthalmoscopes changed all of that allowing us to detect earlier, more subtle changes in the retinal nerve fiber layer. Now patients are treated before visual field defects become apparent.
The Diopsys® Pattern Electroretinograph is the next step in early detection. The PERG will not replace the scanning laser ophthalmoscopes such as the Zeiss Cirrus Optical Coherence Tomographer (OCT) in the diagnosis of glaucoma; however, it gives us another valuable tool in the diagnosis and treatment of glaucoma.