North Texas Eye Care Equipment

Diopsys Visual Evoked Potential

The Diopsys Vision Testing System uses two technologies (VEP & pERG) to objectively measure the functional Diopsys Visual Testing Systemresponses of the entire visual pathway from the anterior segment of the eye to the visual cortex. The device provides quantitative information to support the interpretation and management of many eye diseases and vision deficits, and reports and documents the results of practitioner intervention for tracking patient response. It is non-invasive and provides quick qualitative analsysis of the VEP and pERG waveform and easy quantitative analysis of the amplitude (strength) and latency (speed) of the visual pathway. This device is useful in the diagnosis and progression of glaucoma, multiple sclerosis, macular degeneration, optic nerve disorders, amblyopia, traumatic brain injury, stroke, visual field loss, and many others. This test is typically covered by your major medical insurance and can be done in office.

VEP Testing Procedure:

1. The technician will clean the areas in which the lead wires will be connected with an alcohol wipe.
2. Three electrodes will be connected to the head. (forehead, temple, and back of the head just below the hairline).
3. The lead wires will be connected to the electrodes.
4. The technician will provide the patient with a trial frame that will correct their vision at 36 inches.
5. The lights will be dimmed and the patient will be instructed to stare at the checkerboard pattern on the screen.
6. While staring at the screen, the patient will fixate on the roating X in the center of the screen.
7. After two 20 second tests for each eye, the test is complete.
8. The patient will be instructed to remove the trial frame and the technician will remove all of the electrodes and lead wires.
9. The technician will then clean the areas that the electrodes were applied with alcohol and the test will be complete.
10. It is critical to repeat the test every six or twelve months (depending on the severity of the condition).

pERG Testing Procedure:

1. The technician will clean the areas in which the lead wires will be connected with an alcohol wipe and lid scrubs.
2. Three electrodes will be connected to the head and eyelids. (forehead and below the eyelash line on both eyelids).
3. The lead wires will be connected to the electrodes.
4. The technician will provide the patient with a trial frame that will correct their vision at 20 inches to insure accurate results.
5. The lights will be dimmed and the patient will be instructed to stare at the checkerboard pattern on the screen.
6. While staring at the screen, the patient will fixate on the roating X in the center of the screen.
7. After two 30 second tests for each eye, the test is complete.
8. The patient will be instructed to remove the trial frame and the technician will remove all of the electrodes and lead wires.
9. The technician will then clean the areas that the electrodes were applied with alcohol and the test will be complete.
10. It is critical to repeat the test every six or twelve months (depending on the severity of the condition).