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Br J Ophthalmol 2007;91:1285-1287 doi:10.1136/bjo.2007.114926
  • Scientific report
    • Clinical science - Scientific reports

A comparison of global indices between the Medmont Automated Perimeter and the Humphrey Field Analyzer

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  1. John Landers1,2,
  2. Alok Sharma1,3,
  3. Ivan Goldberg1,4,5,
  4. Stuart Graham1,6
  1. 1
    Eye Associates, Park House, Macquarie Street, Sydney, Australia
  2. 2
    Royal Adelaide Hospital, Adelaide, Australia
  3. 3
    Riverina Eye Care Centre, Wagga Wagga, Australia
  4. 4
    Department of Ophthalmology, University of Sydney, Sydney, Australia
  5. 5
    Glaucoma Services, Sydney Eye Hospital, Sydney, Australia
  6. 6
    Save Sight Institute, University of Sydney, Sydney, Australia
  1. Dr John Landers, Park House, Floor 4, Suite 2, 187 Macquarie Street, Sydney, NSW 2000, Australia; john.landers{at}bigpond.com
  • Accepted 4 March 2007
  • Published Online First 27 March 2007

Abstract

Background: Two commonly used perimeters in Australia are the Humphrey Field Analyzer II (HFA) and the Medmont Automated Perimeter (MAP). Each device describes the visual field in terms of numerical values called global indices; however, these values are not interchangeable between devices. This study was designed to directly compare the global indices of HFA and MAP visual fields.

Methods: 63 subjects who had suspected glaucoma, ocular hypertension or glaucoma, or were normal controls were recruited selectively. Each patient was tested with the MAP and HFA. Global indices were then compared between tests. These included mean deviation (MD) and pattern standard deviation (PSD) from the HFA and average defect (AD) and pattern defect (PD) from the MAP.

Results: The MD and PSD results were strongly correlated with the AD and PD results, respectively. The relationship between them could be described in terms of two polynomial equations: AD = 0.94+1.31(MD)+0.02(MD)2 and PD = 2.21(PSD)–0.05(PSD)2–0.006. These non-linear relationships may be the result of differences in testing method (test stimulus spectrum, number of testing locations or background luminance) or differences in the way each global index was calculated.

Conclusion: The AD and PD results obtained from the MAP may be substituted for the MD and PSD results from the HFA after appropriate conversion.

Footnotes

  • Financial support: This study was not subject to funding from any external source. The authors have no proprietary or financial interest in any of the equipment used in this study.

  • Performed at Eye Associates, Park House, Macquarie Street, Sydney, Australia

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

  • Competing interests: None.

  • Abbreviations:
    AD

    average defect

    HFA

    Humphrey Field Analyzer II

    IOP

    intraocular pressure

    MAP

    Medmont Automated Perimeter

    MD

    mean deviation

    PD

    pattern defect

    PSD

    pattern standard deviation

  • This paper is freely available online under the BMJ Journals unlocked scheme, see http://bjo.bmj.com/info/unlocked.dtl

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