What is a VEP ERG test?

Visual Evoked Potential Test (VEP) The VEP measures the time it takes for a visual stimulus to travel from the eye to the occipital cortex in the brain. The ophthalmologist can determine whether there are abnormalities along the nerve pathway. The test takes about 45 minutes and is painless and non-invasive.

What is ERG and VEP?

Office-based electroretinography (ERG) and visual evoked potential (VEP) tests can supplement existing testing measures for earlier, more accurate diagnosis.

What is visual electrophysiology?

Visual electrophysiology is a collection of advanced techniques used to test the functioning of cells along the full visual pathway – from the retina to the optic nerve to the primary visual cortex in the brain.

What is a multifocal ERG?

The multifocal electroretinogram (mfERG) technique allows local ERG responses to be recorded simultaneously from many regions of the retina. As in the case of the full-field ERG, the ganglion cells contribute relatively little to the response, which originates largely from the outer retina.

What does an abnormal visual evoked potential mean?

This refers to inflammation of the optic nerve, associated with swelling and progressive destruction of the sheath covering the nerve, and sometimes the nerve cable. As the nerve sheath is damaged, the time it takes for electrical signals to be conducted to the eyes is prolonged, resulting in an abnormal VEP.

What is pattern reversal visual evoked potential?

Purpose: : Pattern–reversal visually evoked potential (PRVEP) is widely used as an objective tool to assess the integrity of the maculo–occipital pathway and it is very useful in the diagnosis and monitoring of optic nerve diseases.

What is normal P100 latency?

A P100 latency change of up to at least 11 msec needs to be acknowledged as normal when assessing the clinical significance of changes in P100 latencies in patients. Also, P100 latency changes greater than 11 or 12 msec are very suggestive of an abnormality in the visual pathway.

What is P100 latency?

4.1. A normal P100 latency indicates normal conduction from the retina to the occipital cortex. A delayed potential after stimulation of one eye (with a normal potential after stimulation of the other) implies a defect in conduction in the optic pathway anterior to the chiasm on that side.