BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuElectroretinographyERG; Electrophysiologic testingElectroretinography is a test to measure the electrical response of the eye's light-sensitive cells, called rods and cones. These cells are part of the retina (the back part of the eye). How the Test is Performed While you are in a sitting position, the health care provider places numbing drops into your eyes, so you will not have any discomfort during the test. Your eyes are held open with a small device called a speculum. An electrical sensor (electrode) is placed on each eye.The electrode measures the electrical activity of the retina in response to light. A light flashes, and the electrical response travels from the electrode to a TV-like screen, where it can be viewed and recorded. The normal response pattern has waves called A and B.RetinaThe retina is the light-sensitive layer of tissue at the back of the eyeball. Images that come through the eye's lens are focused on the retina. Th...ImageRead Article Now Book Mark Article The provider will take the readings in normal room light and then again in the dark, after allowing 20 minutes for your eyes to adjust. How to Prepare for the Test No special preparation is necessary for this test. How the Test will Feel The probes that rest on your eye may feel a little scratchy. The test takes about 1 hour to perform. Why the Test is Performed This test is done to detect disorders of the retina. It is also useful for determining if retinal surgery is recommended. Normal Results Normal test results will show a normal A and B pattern in response to each flash. What Abnormal Results Mean The following conditions may cause abnormal results:Arteriosclerosis with damage to the retina ArteriosclerosisAtherosclerosis, sometimes called "hardening of the arteries," occurs when fat, cholesterol, and other substances build up in the walls of arteries. ...ImageRead Article Now Book Mark Article Congenital night blindness Congenital retinoschisis (splitting of the retinal layers) Giant cell arteritis Giant cell arteritisGiant cell arteritis (GCA) is inflammation and damage to the blood vessels that supply blood to the head, neck, upper body and arms. It is also call...ImageRead Article Now Book Mark Article Medicines (chloroquine, hydroxychloroquine) Mucopolysaccharidosis MucopolysaccharidosisMucopolysaccharides are long chains of sugar molecules that are found throughout the body, often in mucus and in fluid around the joints. They are m...Read Article Now Book Mark Article Retinal detachment Retinal detachmentRetinal detachment is a separation of the light-sensitive membrane (retina) in the back of the eye from its supporting layers.ImageRead Article Now Book Mark Article Rod-cone dystrophy (retinitis pigmentosa) (retinitis pigmentosa)Retinitis pigmentosa is an eye disease in which there is damage to the retina. The retina is the layer of tissue at the back of the inner eye. This...ImageRead Article Now Book Mark Article Trauma Vitamin A deficiencyVitamin A deficiencyVitamin A is a fat-soluble vitamin that is stored in the liver. There are two types of vitamin A that are found in the diet. Preformed vitamin A is f...ImageRead Article Now Book Mark Article Risks The cornea may get a temporary scratch on the surface from the electrode. Otherwise, there are no risks with this procedure. Considerations You should not rub your eyes for an hour after the test, as this could injure the cornea. Your provider will talk to you about the results of the test and what they mean for you.Open ReferencesReferencesBaloh RW, Jen JC. Neuro-ophthalmology. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 396.Reichel E, Klein K. Retinal electrophysiology. In: Yanoff M, Duker JS, eds. Ophthalmology. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 6.9.Tsang SH, Holder GE. Clinical electrophysiology. In: Sadda SVR, Sarraf D, Freund B, et al, eds. Ryan's Retina. 7th ed. Philadelphia, PA: Elsevier; 2023:chap 9.AllVideoImagesTogContact lens electrode on eye - illustration The electroretinography (ERG) test measures the electrical response of the retina to light. It is performed by placing an electrode on the cornea of the eye after it has been numbed with eye drops. Disorders of the retina can be evaluated with this test. It can also help to determine if retinal surgery may be helpful.Contact lens electrode on eyeillustrationContact lens electrode on eye - illustration The electroretinography (ERG) test measures the electrical response of the retina to light. It is performed by placing an electrode on the cornea of the eye after it has been numbed with eye drops. Disorders of the retina can be evaluated with this test. It can also help to determine if retinal surgery may be helpful.Contact lens electrode on eyeillustration Tests for Electroretinography ElectroretinographyRelated Information Retinitis pigmentosa(Condition)Atherosclerosis(Condition)Giant cell arteritis(Condition)Mucopolysaccharides(Special Topic)Retinal detachment(Condition)Vitamin A(Nutrition)Vitamins and Phytonutrients - InDepth(In-Depth) Review Date: 8/22/2022 Reviewed By: Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David C. 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ElectroretinographyERG; Electrophysiologic testingElectroretinography is a test to measure the electrical response of the eye's light-sensitive cells, called rods and cones. These cells are part of the retina (the back part of the eye). How the Test is Performed While you are in a sitting position, the health care provider places numbing drops into your eyes, so you will not have any discomfort during the test. Your eyes are held open with a small device called a speculum. An electrical sensor (electrode) is placed on each eye.The electrode measures the electrical activity of the retina in response to light. A light flashes, and the electrical response travels from the electrode to a TV-like screen, where it can be viewed and recorded. The normal response pattern has waves called A and B.RetinaThe retina is the light-sensitive layer of tissue at the back of the eyeball. Images that come through the eye's lens are focused on the retina. Th...ImageRead Article Now Book Mark Article The provider will take the readings in normal room light and then again in the dark, after allowing 20 minutes for your eyes to adjust. How to Prepare for the Test No special preparation is necessary for this test. How the Test will Feel The probes that rest on your eye may feel a little scratchy. The test takes about 1 hour to perform. Why the Test is Performed This test is done to detect disorders of the retina. It is also useful for determining if retinal surgery is recommended. Normal Results Normal test results will show a normal A and B pattern in response to each flash. What Abnormal Results Mean The following conditions may cause abnormal results:Arteriosclerosis with damage to the retina ArteriosclerosisAtherosclerosis, sometimes called "hardening of the arteries," occurs when fat, cholesterol, and other substances build up in the walls of arteries. ...ImageRead Article Now Book Mark Article Congenital night blindness Congenital retinoschisis (splitting of the retinal layers) Giant cell arteritis Giant cell arteritisGiant cell arteritis (GCA) is inflammation and damage to the blood vessels that supply blood to the head, neck, upper body and arms. It is also call...ImageRead Article Now Book Mark Article Medicines (chloroquine, hydroxychloroquine) Mucopolysaccharidosis MucopolysaccharidosisMucopolysaccharides are long chains of sugar molecules that are found throughout the body, often in mucus and in fluid around the joints. They are m...Read Article Now Book Mark Article Retinal detachment Retinal detachmentRetinal detachment is a separation of the light-sensitive membrane (retina) in the back of the eye from its supporting layers.ImageRead Article Now Book Mark Article Rod-cone dystrophy (retinitis pigmentosa) (retinitis pigmentosa)Retinitis pigmentosa is an eye disease in which there is damage to the retina. The retina is the layer of tissue at the back of the inner eye. This...ImageRead Article Now Book Mark Article Trauma Vitamin A deficiencyVitamin A deficiencyVitamin A is a fat-soluble vitamin that is stored in the liver. There are two types of vitamin A that are found in the diet. Preformed vitamin A is f...ImageRead Article Now Book Mark Article Risks The cornea may get a temporary scratch on the surface from the electrode. Otherwise, there are no risks with this procedure. Considerations You should not rub your eyes for an hour after the test, as this could injure the cornea. Your provider will talk to you about the results of the test and what they mean for you.Open ReferencesReferencesBaloh RW, Jen JC. Neuro-ophthalmology. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 396.Reichel E, Klein K. Retinal electrophysiology. In: Yanoff M, Duker JS, eds. Ophthalmology. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 6.9.Tsang SH, Holder GE. Clinical electrophysiology. In: Sadda SVR, Sarraf D, Freund B, et al, eds. Ryan's Retina. 7th ed. Philadelphia, PA: Elsevier; 2023:chap 9.