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. ...
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. ...
Categories: Medical tests | Ophthalmology An electrooculogram (EOG) is a recording of the resting potential of the retina. ... The International Society for Clinical Electrophysiology of Vision (ISCEV) is an association that promotes research and applications of electrophysiological methods (e. ... A visual evoked potential (VEP) is an evoked potential caused by sensory stimulation of a subjects visual field. ...
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.
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