Not every cause of vision loss can be seen just by looking at the eye. Our electrophysiology unit measures the tiny electrical signals the retina and visual pathway generate in response to light — giving our retina, neuro-ophthalmology, and pediatric teams objective data long before damage might be visible on examination alone.
Conditions we treat
- Inherited and degenerative retinal diseases (e.g. retinitis pigmentosa)
- Unexplained vision loss in infants and young children
- Optic nerve disorders where nerve conduction may be affected
- Suspected cone or rod dysfunction
- Vision problems that don't match what's visible on retinal examination or imaging
Diagnosis & technology
- ERG (Electroretinogram) — the overall electrical response of the retina to light
- Multifocal ERG (mfERG) — tests many small retinal areas separately to locate damage
- EOG (Electro-oculogram) — resting electrical potential, useful for retinal pigment epithelium conditions
- VEP (Visual Evoked Potential) — electrical activity along the whole visual pathway to the brain
Treatment options
-
These are diagnostic tests, not treatments — results guide the treatment plan set by the relevant specialty department
-
A clear result can rule out a serious retinal/neurological cause; an abnormal one helps confirm diagnosis and decide on further imaging or genetic testing
When to seek care
Ask your BSEH doctor about electrophysiology testing if you or your child have unexplained vision loss or night blindness, a family history of inherited retinal disease, or vision that doesn't match what's visible on a standard eye exam.
Frequently asked questions
Is the test painful?
No, though it can feel unusual — small sensor electrodes near the eye and on the skin around the forehead/temples. Some mild foreign-body sensation for a few hours afterward is possible.
How long does the test take?
A single ERG typically takes 30–60 minutes including dilation time; combined tests can take up to two hours.
Do I need to prepare beforehand?
Pupils are usually dilated, so vision will be blurry and light-sensitive for hours afterward — arrange transport and bring sunglasses.
Ready to see us?
Call the appointment desk, or book online — we will confirm your time by phone.
Sources consulted: Moran Eye Center — Electrophysiology Eye Testing , Nationwide Children's Hospital — Visual Electrophysiology . General medical information — not a substitute for professional diagnosis. Content pending final medical review by BSEH doctors before publish.
← View all specialties