An electroretinography (ERG) test, also known as an electroretinogram, measures the electrical response of the light-sensitive cells in your eyes. These cells are known as rods and cones. They form part of the back of the eye known as the retina.

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.

How does an EOG work?

An EOG records eye movement by detecting a voltage difference between the cornea and retina. As the eye moves, the vector of this electric field changes with respect to recording electrodes placed in the skin at fixed points.

What does an Electrooculogram measure?

The electrooculogram (EOG) measures the cornea-positive standing potential relative to the back of the eye. By attaching skin electrodes outside the eye near the lateral and medial canthus, the potential can be measured by having the patient move the eyes horizontally a set distance.

Who invented the Electroretinogram?

The first human ERG was recorded in 1877 by Scottish chemist and physicist Sir James Dewar. James Dewar and John Gray McKendrick independently suggested that the biological potential was from retina. In 1908, Einthoven and Jolly divided the ERG response into three components: A-wave, B-wave, and C-wave.

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 the point of an EOG?

The electro-oculogram (EOG) investigates abnormalities of the outermost layer of the retina, the retinal pigment epithelium, allowing the early diagnosis of some inherited macular diseases such as Best disease. The EOG is used to assess the function of the pigment epithelium.

What is an EEG signal?

The electroencephalogram (EEG) is a recording of the electrical activity of the brain from the scalp. The recorded waveforms reflect the cortical electrical activity. Signal intensity: EEG activity is quite small, measured in microvolts (mV).

What is eye anatomy and physiology?

Eye Anatomy and Physiology. Eyes are spheroid shape organs fitted into the two orbitals of the skull. There are three major parts in each eye like. The sclera (fibrous layer) Choroid layer; Retina; Eyes diagram showing the entire structure The sclera. It makes up the outermost part of eye anatomy.

What is the pathway of light through the eye?

Light passes through the front of the eye (cornea) to the lens. The cornea and the lens help to focus the light rays onto the back of the eye (retina). The cells in the retina absorb and convert the light to electrochemical impulses which are transferred along the optic nerve and then to the brain.

What is ophthalmic electrophysiology testing?

Ophthalmic Electrophysiology Electrophysiology testing includes a battery of tests which can be used to provide information about the visual system beyond the standard clinical examination of the eye. Electroretinography (ERG) and Electro-oculography (EOG) are two of the tests conducted in the Ophthalmic Electrophysiology Laboratory.

What are electelectrical responses from the eye?

Electrical responses from the eye are recorded with an electrode just as in conventional ERG recording, but the special nature of the stimulus and analysis produces a more detailed map of where in the central retina ERG responses are normal or abnormal. This can help distinguish among different diseases.