Canis ISSN: 2398-2942

Electroretinography

Contributor(s): Natasha Mitchell

Introduction

  • Measures the potential difference generated across the retina when stimulated by light.
  • This provides a means of measuring retinal function.
  • The electroretinogram (ERG) consists of a negative 'a' wave, positive 'b' wave and a positive 'c' wave which correspond to the photoreceptors, Muller's cells and retinal pigment epithelium respectively.
  • Many modifications possible to distinguish between rod and cone response.
  • Pattern electroretinograhy is used in research settings to investigate retinal ganglion cell function within the inner retina in cases of glaucoma.
  • Visual evoked potentials are used in a research setting to investigate the central visual pathways.

Uses

  • The most common indication in clinical practice is evaluation of retinal function prior to cataract surgery, where fundus assessment is not possible due to the lens opacity.
  • Investigation of sudden onset blindness when the fundus looks normal; most often to distinguish sudden acquired retinal degeneration syndrome Retina: sudden acquired retinal degeneration syndrome from retrobulbar (brain or optic nerve disease) blindness Blindness.
  • Investigation or early detection of various inherited retinopathies (dystrophy or degeneration).

Advantages

  • Objective, repeatable test.
  • Non-invasive.
  • Equipment becoming more affordable and portable systems available.

Disadvantages

  • Specialized equipment and training required.

Requirements

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Preparation

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Procedure

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Aftercare

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Outcomes

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Further Reading

Publications

Refereed papers


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