ELECTRORETINOGRAM BASICS PDF

Electroretinography measures the electrical responses of various cell types in the retina, including the photoreceptors (rods and cones), inner retinal cells. Basic mechanisms of electrical field generation in the tissue. Recording protocols Electroretinography (ERG) alone does not give you necessarily a diagnosis. Electroretinogram: An electrical diagnostic test of retinal function in situ. Electro – part Show you the basic clinical test; Show some research examples. The Eye .

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Basiccs, the temporal properties of P-II are of value to the clinician. Gotch 2 was the first to report that the response of the eye to a light flash hasics of two waves; first the cornea became negative and then a positive wave of larger amplitude appeared. The major contribution comes from light-induced activity in ON-center bipolar cells.

Moreover, an ERG can also be used to monitor disease progression or evaluating for retinal toxicity with various drugs or from a retained intraocular foreign body. Similar articles in PubMed. Xu X, Karwoski CJ. Reduced bssics amplitudes which improve to normal values after longer variable perior of dark adaptation. Figure 3a A schematic representation of the extracellular currents that are formed after light stimulation. The ERG responses were elicited by a series of red light stimuli of moderate to bright intensities that were applied during background illumination.

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Electroretinogram

Depth recordings of the ERP with microelectrodes and intracellular recordings led to the conclusion that the ERP originated in the photoreceptors 66 The average continuous line and the range dashed lines are given. The oscillatory potentials of the mudpuppy retina. Due to the massed retinal electrical response, small retinal lesions may not be revealed in ffERG recordings. To derive the relationship between P 3 and time for the entire ERG range, very bright flashes that saturate the photoreceptors i.

Generation of b-wave currents in the elextroretinogram retina. Figure 2b The ERG of a cat in response to a 2-sec light stimulus. An evaluation of retinal electrical anisotropy.

Electroretinogram – EyeWiki

Temporal aspects of the human electroretinogram; a study elwctroretinogram the implicit time-amplitude relationship of the b-wave. Analysis of the intra retinal electroretinogram in the intact cat eye. Among the minor components of the ERG, only the oscillatory potentials and the d-wave are used for clinical assessment of retinal function.

II Pharmacological analysis of the b-wave and M-wave. Therefore, in situations where the a- and b-waves remain normal in waveform and amplitude, OP recording scans indicate mild retinal ischemia in the inner retina For the fraction of the unit of energy erg, see micro-erg.

Human cone receptor activity: Evidently, direct neuronal contributions cause the M-waves, and the major contribution is to the OFF wave An example is shown in Fig. Now, the electroretinogram response is commonly abbreviated to the ERG. Therefore, the ERG c-wave can be used to assess the functional integrity of the photoreceptors, the pigment epithelial cells, and the interactions between them.

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The effects of color on the dark-adapted ERG response of human. In contrast, if the same light stimulus is applied after the subject is kept in darkness for about 30 min, the ERG is of considerably larger amplitude elecrroretinogram 4 folds and is characterized by slow temporal properties—time to peak electroretinkgram the b-wave is about 60 ms Fig.

Support Center Support Center. Electroretimogram over 50 years, since the analysis by Granit 5 of the ERG components, the a-wave has been used to assess the functional integrity of the photoreceptors.

Retrieved from ” http: Fluorescein angiography Fundus photography Corneal topography Optical coherence tomography Electrodiagnosis: The a-wave is used as the independent variable and is used together with the normal b-wave: