What is electrophysiology?
Electrophysiology involves specialized testing that measures the electrical activity of the visual system. These tests help us understand how well the retina (the light-sensitive layer at the back of the eye) and the visual pathways to the brain are functioning. This type of testing is crucial for diagnosing and managing a variety of eye and neurological conditions.
Who needs this testing?
Our department provides services for both adults and children across the Atlantic provinces. Patients are typically referred to us by ophthalmologists or neurologists. We are a consulting service, meaning that the results of our tests are sent directly back to the referring physician to assist in your ongoing care.
What to expect during your visit
When you come for testing, your visit will include a comprehensive eye exam, including ocular (eye) and health history, vision testing, contrast sensitivity and color vision testing, eye alignment, and a pupil exam. Electrodiagnostic testing will then be performed, small stickers with long wires will be placed on your head—almost like spaghetti noodles! After the testing, ocular photography will be done to capture detailed images of the back of your eyes.
Please refer to your appointment letter to verify if your eyes will need to be dilated for testing, if so, you will not be able to drive yourself home after the appointment.
Common electrodiagnostic tests
Visual evoked potential (VEP)
The VEP assesses the electrical activity of the brain in response to a visual target, such as a flash of light or a checkerboard pattern. For this test, small sensors (stickers) are placed on the scalp (head). You’ll be asked to focus on a screen showing a checkered pattern, or a big flashlight, and one eye will be covered—just like a pirate! The test measures how quickly and accurately your brain responds to visual signals. This test does not require any eye drops.
Electroretinogram (ERG)
The ERG measures the electrical responses of the retina (the back of the eye) to flashes of light. During the test, small sensors (stickers) are placed on your forehead and temples, and a tiny thread is positioned along your lower eyelid. The test is divided into two parts: one performed in the dark and the other in the light. You will see flashes of light in various colors and brightness levels, and the sensors will capture your retina's response. This test requires dilating eye drops.
For some children, we can perform a simplified version of the ERG, which does not require any eye drops. In this version, the small thread is replaced with a sticker placed on the skin below the eye.
Available resources
Quiet waiting room
For patients and families who would benefit from a private and quiet space, separate from the main waiting room, this option is available upon request. This space is also available for mothers and newborns who prefer privacy for breastfeeding. Please notify the administrative staff at registration if you prefer to wait in the quiet room.
Accessibility
Our testing devices are mobile and can be used in a patient’s preferred chair if needed, ensuring that testing can be done in the most comfortable setting for you or your child.
Interpretation and Language Services
In-person interpretation services are available but must be requested prior to your appointment. To request in person interpretation services, please call 902-470-8020. We also offer onsite Language Line Insight video interpreting, which is best suited for short, intermittent interpretation needs
A hospital visit can be a positive experience for children when they know what to expect. Child Life Services offer strategies and tools to make the visit more comfortable and reassuring for your child. In collaboration with Child Life, our eye clinic provides Bravery beads to celebrate children’s courage in completing their electrodiagnostic testing. A dedicated Child Life Services representative is also available to assist with any specific needs. For more details, please visit the Child Life Services page.
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