title: The effects of pupil size on the multifocal electroretinogram.
abstract: This is an investigation of the effect of changing the pupil diameter on the P1 amplitude and latency of the multifocal electroretinogram (mfERG). MfERGs were recorded using a custom built wide field electrophysiological system. An array of 61 empirically scaled hexagons was used to stimulate the visual field. The duration of overall recording period was 8 min, segmented into 16 intervals each lasting 30 s. A combination of mydriatics and miotics were used to pharmacologically alter the pupil size and diameters between 1 and 10 mm were measured. There was a reduction in mfERG P1 amplitude in some cases greater than 50% (mfERG P1 amplitude 53 nV at 8 mm to 25 nV at 1 mm), with a change in pupil diameter of 7 mm. The mfERG P1 latency increased in some cases by as much as 8 ms in the central 40 degrees (mfERG P1 latency 39 ms at 8 mm to 47 ms at 1 mm). These results suggest that pupil size has significant effects on mfERG P1 amplitude and latency.
authors.affiliation: Electrodiagnostic Imaging Unit, Tennent Institute of Ophthalmology, Gartnavel General Hospital, Glasgow, Scotland, UK.
authors.forename: P
authors.initials: P
authors.lastname: Gonzalez
authors.forename: S
authors.initials: S
authors.lastname: Parks
authors.forename: F
authors.initials: F
authors.lastname: Dolan
authors.forename: D
authors.initials: D
authors.lastname: Keating
mesh_terms: D004596:Electroretinography; D006801:Humans; D008916:Miotics / Q000494:pharmacology; D009184:Mydriatics / Q000494:pharmacology; D010862:Pilocarpine / Q000494:pharmacology; D011680:Pupil / Q000187:drug effects / Q000502:physiology*; D011930:Reaction Time; D012160:Retina / Q000502:physiology*; D014331:Tropicamide / Q000494:pharmacology
chemical_list: D008916:Miotics; D009184:Mydriatics; D010862:Pilocarpine; D014331:Tropicamide