Department of Electrophysiology

The Department of Electrophysiology of the Lab of Vision and Optics provides diagnostic services of high quality, guaranteed by the use of advanced equipment such as the Ganzfelt dome (Colordome, Diagnosys LLC), a high resolution screen, a differential signal amplifier (CED 1902 amplifier), a timing unit (CED Micro 1401), a photometer and a scpectroradiometer.

All examinations are prepared in accordance with the standards of the International Society of Clinical Electro-Vision (ISCEV) by trained personel. In all tests recording electrodes are used and there is no need of any kind of anaesthesia.

The electrophysiological tests provide us with information on the fuction of the optical path from the eye to our brain via the optic nerve. Depending on which stage of the process of the optical sign they monitor, we divide them as following:

1. The evoked by diffuse light electroretinogram (flash ERG): this is the main test for diagnosing diseases of the retina, such as retinitis pigmentosa, retinal dystrophies and any kind of macula degeneration (ie cone dystrophies, Staargardt disease, Leber disease etc). Using this test we can test the integrity of the two kinds of photoreceptors -cones and rodes- separately and at the same time the separation of different types of cones (S cones) is feasible.

2. The electroretinogram evoked by stimulation (pattern ERG): the pERG reflects activity in the gagglion layer and it is the examination of choice for checking the integrity of central vision, ie the functionality of the macula. The visual stimuli that are typically used consist of a "chessboard" oe black and white squares of alternating form. Measurments are performed separately for each eye.

3. The electrooculargram: it is used to check the integrity of the melachroun epithelium. It is the examination of choice for patients that suffer from the disease of Best.

4. The Visual Evoked Potentials (VEP): this test records group responses of ganglion cells in the pre-cortical visual tract and brain neurons of the occipital lobe. Therefore VEP are used in the diagnosis of diseases of the optic nerve. For the examination we use the same pattern as in pERG. 

For more information for patients, please visit Electrophysiology of Vision