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Topography of the frequency doubling perimetry visual field compared with that of short wavelength and achromatic automated perimetry visual fields
  1. J Landers1,4,
  2. A Sharma1,
  3. I Goldberg1,2,3,
  4. S Graham1,3
  1. 1Eye Associates, Park House, Macquarie Street, Sydney, New South Wales, Australia
  2. 2Sydney Eye Hospital, University of Sydney, Sydney, New South Wales, Australia
  3. 3Save Sight Institute, University of Sydney, Sydney, New South Wales, Australia
  4. 4Department of Medicine, University of Adelaide, Adelaide, South Australia, Australia
  1. Correspondence to: Dr John Landers Park House, Floor 4, Suite 2, 187 Macquarie Street, Sydney, NSW 2000, Australia; john.landers{at}bigpond.com

Abstract

Background: Traquair described the topography of visual field sensitivity as a “hill” or “island” of vision. Achromatic automated perimetry (AAP) demonstrates this shape of the visual field in photopic conditions. Techniques claimed to target the magnocellular pathway (frequency doubling perimetry, FDP) and those using a stimulus targeting the koniocellular pathway (short wavelength (or blue on yellow) automated perimetry, SWAP), might produce one that is different. The authors compared the visual field topography from FDP with those of SWAP and AAP, to investigate whether there were significant differences in their shape.

Method: A sample of 51 patients with previously confirmed normal perimetry were recruited; either low risk glaucoma suspects or normal controls. AAP, SWAP, and FDP perimetry was performed in random order on the same day. The topography of each field was analysed to determine its average shape and to compare results in the same individuals.

Results: The topography of the visual field produced by each perimeter differed significantly. While all three had maximal sensitivity centrally, over the 24 degrees from the centre to the periphery, mean sensitivities decreased by 4.9 decibels (dB) for AAP and 7.3 dB for SWAP, while FDP sensitivities by just 1.8 dB over 20 degrees (the extent of the FDP field). FDP mean sensitivities decreased by approximately 0.3 dB with every 10 year increase in age, compared with 1 dB for AAP and 2 dB for SWAP.

Conclusion: While the topography of the SWAP (koniocellular) field is steeper than corresponding AAP fields, that of the FDP (magnocellular) visual field was considerably flatter. The difference in this shape may reflect retinotopic or cortical mechanisms, which are specific to the magnocellular pathways.

  • AAP, achromatic automated perimetry
  • FDP, frequency doubling perimetry
  • GHT, glaucoma hemifield test
  • IOP, intraocular pressure
  • PSD, pattern standard defect
  • SWAP, short wavelength automated perimetry
  • frequency doubling
  • achromatic
  • perimetry
  • topography
  • magnocellular pathway
  • short wavelength
  • AAP, achromatic automated perimetry
  • FDP, frequency doubling perimetry
  • GHT, glaucoma hemifield test
  • IOP, intraocular pressure
  • PSD, pattern standard defect
  • SWAP, short wavelength automated perimetry
  • frequency doubling
  • achromatic
  • perimetry
  • topography
  • magnocellular pathway
  • short wavelength
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Footnotes

  • Financial support: This study was not subject to funding from any external source.

  • Financial disclosure: The authors have no proprietary or financial interest in any of the equipment used in this study.

    Ethical approval: Ethical approval for this study was obtained from the South Eastern Sydney Area Health Services Clinical Research Ethics Committee.

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