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Multifocal Electroretinograms
Published on: December 4, 2011
Relatively spared central multifocal electroretinogram responses in acute quinine toxicity
Muhammad Usman Saeed1, Carmel Noonan, Richard Hagan
1St Pauls Eye Unit, Royal Liverpool University Hospital, Liverpool, UK. musmansaeed@aol.com
BMJ Case Reports
|June 14, 2012
Summary
Quinine overdose can cause severe vision loss, but the macula may be spared. This suggests retinal damage might stem from vascular issues during poisoning.
Area of Science:
- Ophthalmology
- Toxicology
- Neuroscience
Background:
- Quinine overdose can lead to significant visual impairment.
- Electrodiagnostic testing is crucial for assessing retinal function after toxic exposure.
Observation:
- A 71-year-old man experienced severe vision loss after quinine overdose, with initial visual acuity of light perception.
- Follow-up testing revealed visual acuity of 6/6 (right eye) and 6/12 (left eye) with constricted visual fields.
- Multifocal electroretinogram (ERG) showed electronegative responses in peripheral retina and a reduced electropositive response centrally.
Findings:
- The study observed bilaterally negative ERGs in a patient with quinine toxicity.
- The macula/fovea, supplied by the choroid, appeared relatively spared from the toxic effects.
- This pattern resembles findings in bilateral vascular electronegative ERGs.
Implications:
- Quinine's retinal toxicity may be linked to vascular occlusion or severe ischemia during acute poisoning.
- The relative sparing of the macula suggests a potential mechanism of toxicity.
- Further research into quinine's vascular effects on the retina is warranted.
