What is a mfERG?

What is a mfERG?

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 ERG test show?

Electroretinography (ERG) is an eye test that is used to detect abnormal function of the retina, which is the light-detecting portion of the eye. In this test, the rods, cones and light sensitive cells of the eyes are examined.

What does electroretinography measure?

Definition. The electroretinogram (ERG) is a diagnostic test that measures the electrical activity of the retina in response to a light stimulus. The ERG arises from currents generated directly by retinal neurons in combination with contributions from retinal glia.

What does multifocal ERG measure?

The multifocal electroretinogram (mfERG) is a more recent advancement in electroretinographic testing, which enables a rapid assessment of retinal function from many areas at the same time. Using a contrast-reversing stimulus. There are standard protocols for eliciting the retinal electrical response.

Why do a person need an electroretinography test?

Why do I need an electroretinography test? Your doctor may perform an ERG to determine if you have an inherited or acquired disorder of the retina, such as: retinitis pigmentosa, which is a genetic disease causing loss of peripheral and night vision.

What does an abnormal ERG mean?

What does an abnormal ERG mean? An abnormal ERG result suggests abnormal function of the retina which may be caused by a number of diseases of the retina. The results of the ERG will be discussed with your doctor.

What does a normal ERG look like?

A normal ERG shows an a-wave (photoreceptor activity) and b-wave (Muller and bipolar cells activity) patterns in dark-adapted (scotopic) and light-adapted (photopic) settings. Wave patterns that are diminished in size or delayed or prolonged in time provide clues about the types of damaged cells.

Why do a person needs an electroretinography test?

What are A and B waves in ERG?

The a-wave, sometimes called the “late receptor potential,” reflects the general physiological health of the photoreceptors in the outer retina. In contrast, the b-wave reflects the health of the inner layers of the retina, including the ON bipolar cells and the Muller cells (Miller and Dowling, 1970).

Is electroretinography painful?

Electroretinography (ERG) Responses to flashes of light are measured via electrodes placed on the surface of the eye. It is a painless test.

What is electrophysiology eye test?

Electrophysiology tests check to see how well this visual nerve pathway sends the electrical signals needed for vision. These tests measure electrical activity that occurs in your eye when you look at something. Electrophysiology includes different tests that measure how well the retina works.

What is ERG retina?

Full Field Electroretinography (ERG) is a test used to detect abnormal function in the retina (the light-detecting portion of the eye).

What does the A-wave represent ERG?

Congenital stationary night blindness – normal a-wave indicates normal photoreceptors; absent b-wave indicates abnormality in the bipolar cell region.

What does B wave on the Electroretinogram show?

The b wave of the human electroretinogram (ERG) is widely believed to reflect the activation of on-bipolar cells. However, the shape of the b wave is also influenced by the activity of other cell types.

What is the A-wave in ERG?

The full-field, or Ganzfeld, ERG measures a mass response generated by cells from the entire retina. Photoreceptors generate the initial negative component, ora-wave, whereas Müller cells and bipolar cells are responsible for the later, positive,b-wave.