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Encyclopedia > Electroretinography

Electroretinography, is used to measure the electrical responses of various cell types in the retina, including the light-sensitive cells (rods and cones) and the ganglion cells. Electrodes are placed on the cornea and the skin near the eye. During a recording, the patient is watching a standardized stimulus and the resulting signal is interpreted in terms of its amplitude (voltage) and time course. Stimuli include flashes (flash ERG) and reversing checkerboard patterns (pattern ERG). Applications are predominantly in ophthalmology, where the electroretinogram (ERG) is used for the diagnosis of various retinal diseases: Human eye cross-sectional view. ... Photoreceptor cells are contained in the retina and are responsible for transducing, or converting, light into signals that can be ultimately transmitted to the brain via the optic nerve. ... Normalised absoption spectra of human rod (R) and cone (S,M,L) cells. ... Normalised absorption spectra of human cone (S,M,L) and rod (R) cells Cone cells, or cones, are cells in the retina which only function in relatively bright light. ... A ganglion cell (or sometimes called a gangliocyte) is a type of neuron located in the retina that receives visual information from photoreceptors via various intermediate cells such as bipolar cells, amacrine cells, and horizontal cells. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ... The cornea is the curved, transparent layer that covers the front part of the eye and protects its inner structures. ... An eye is an organ that detects light. ... A stimulus is the following: In physiology, a stimulus (physiology) is something external that elicits or influences a physiological or psychological activity or response. ... An optical refractor in use. ...

  • Retinitis pigmentosa and related hereditary degenerations
  • Retinitis pigmentosa sine pigmento
  • Retinitis punctata albescens
  • Leber's congenital amaurosis
  • Choroideremia
  • Gyrate atrophy of the retina and choroid
  • Goldman-Favre syndrome
  • Congenital stationary night blindness - normal a-wave indicates normal photoreceptors; absent b-wave indicates abnormality in the bipolar cell region.
  • X-linked juvenile retinoschisis
  • Achromatopsia
  • Cone dystrophies
  • Disorders mimicking retinitis pigmentosa

Normal vision. ... Nyctalopia (Greek for night blindness) is a condition making it difficult or impossible to see in the dark. ... Photoreceptors are light-sensitive proteins involved in the function of photoreceptor cells. ... As a part of the retina, the bipolar cell exists between photoreceptors (rod cells and cone cells) and ganglion cells. ... Maskun is a medical condition (also called achromatopsia) characterized by a low cone count or lack of function in cone cells; these are the light receptors responsible for colour perception. ...

See also

  Results from FactBites:
Electroretinography (ERG) Eye Test and Procedure Information on MedicineNet.com (454 words)
Electroretinography is an eye test used to detect abnormal function of the retina (the light-detecting portion of the eye).
During the test, an electrode is placed on the cornea (at the front of the eye) to measure the electrical responses to light of the cells that sense light in the retina at the back of the eye.
Decreased electroretinography values may indicate abnormal function of the retina as occurs with conditions such as arteriosclerosis (hardening of the arteries) involving the eye vessels, giant cell arteritis with eye involvement, metabolic diseases called mucopolysaccharidoses, detachment of the retina, siderosis(excess iron), and vitamin A deficiency.
Electroretinography definition - Medical Dictionary definitions of popular medical terms easily defined on MedTerms (260 words)
A test in which the electrical potentials generated by the retina of the eye are measured when the retina is stimulated by light.
An abnormal ERG is found in conditions such as arteriosclerosis of the retina, detachment of the retina, and temporal arteritis with eye involvement.
Electroretinography - Read about electroretinography (ERG), an eye test where electrodes placed on the cornea measure electrical responses to light to try to detect abnormal retinal function.
  More results at FactBites »



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