What is the role of electroretinography (ERG) in the workup of central retinal vein occlusion (CRVO)?

Updated: Apr 18, 2019
  • Author: Lakshmana M Kooragayala, MD; Chief Editor: Douglas R Lazzaro, MD, FAAO, FACS  more...
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Electroretinography (ERG) is another useful test to evaluate the functional status of the retina and to classify CRVO. [18, 24, 25] In ERG waveform, b-wave and a-wave are produced by the inner retina and the outer retina, respectively. In central retinal vein obstruction, perfusion of the inner retina is affected, so that the amplitude of the b-wave is decreased relative to the a-wave; the b-to-a ratio has been shown to be reduced. Some studies indicate that a b-to-a ratio of less than 1 suggests an ischemic central retinal vein obstruction.

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