Visual Diagnosis Tests « QEDIC

Visual Diagnosis Tests

There are a number of tests performed at QEDIC.  These include:

Electro-oculogram (EOG) –measures retinal function with standardised eye movements.

Electroretinogram (ERG) – measures the electrical responses of various cell types in the retinal and is used to diagnosis various retinal diseases.  Variations of this test include: the Bright Flash Electroretinogram (Bright Flash ERG), the Pattern Electroretinogram (PERG) which is used to assess retinal ganglion cell functioning diseases like glaucoma, and the Multifocal Electroretinogram (MFERG) which is used to record responses for different retinal locations.

Visual Evoked Potential (VEP) – measures the functional integrity of the visual pathways from the retina to the visual cortex of the brain via the optic nerve.  Variations of this test include: the Flash Visual Evoked Potential (Flash VEP), Pattern Visual Evoked Potential (Pattern VEP), the Special Visual Evoked Potential (Special VEP), and the Multifocal Visual Evoked Potential

Other tests performed include Colour Vision.

Indications for Specific Tests

Provisional Diagnosis EOG ERG Bright Flash ERG PERG Flash VEP Pattern VEP Special VEP mfERG mfVEP
Inherited retinal dystrophies
Vascular diseases (inc. diabetes)
Opaque media or trauma
Retrobulbar neuritis
Unexplained visual loss
Infant with questionable vision
Toxic & neutritional eye disease
Suspected intracranial lesion


For further information on electro-diagnostics tests and their indications, please visit