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Br J Ophthalmol 2008;92:569-573 doi:10.1136/bjo.2007.135012
  • Education

Practical recommendations for measuring rates of visual field change in glaucoma

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  1. B C Chauhan1,
  2. D F Garway-Heath2,
  3. F J Goñi3,
  4. L Rossetti4,
  5. B Bengtsson5,
  6. A C Viswanathan2,
  7. A Heijl5
  1. 1
    Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Canada
  2. 2
    Moorfields Eye Hospital and UCL and Institute of Ophthalmology NIHR Biomedical Research Centre, London, UK
  3. 3
    Barcelona Glaucoma Centre, USP-Instituto Oftalmológico de Barcelona, Barcelona, Spain
  4. 4
    Department of Ophthalmology, Eye Clinic, University of Milan, San Paolo Hospital, Milan, Italy
  5. 5
    Department of Ophthalmology, Malmo University Hospital, Lund University, Lund, Sweden
  1. B C Chauhan, Department of Ophthalmology and Visual Sciences, Dalhousie University, 2nd Floor Centennial Building, Queen Elizabeth II Health Sciences Centre, Halifax, Canada B3H 2Y9; bal{at}dal.ca
  • Accepted 27 December 2007
  • Published Online First 22 January 2008

Abstract

To date, there has been a lack of evidence-based guidance on the frequency of visual field examinations required to identify clinically meaningful rates of change in glaucoma. The objective of this perspective is to provide practical recommendations for this purpose. The primary emphasis is on the period of time and number of examinations required to measure various rates of change in mean deviation (MD) with adequate statistical power. Empirical data were used to obtain variability estimates of MD while statistical modelling techniques derived the required time periods to detect change with various degrees of visual field variability. We provide the frequency of examinations per year required to detect different amounts of change in 2, 3 and 5 years. For instance, three examinations per year are required to identify an overall change in MD of 4 dB over 2 years in a patient with average visual field variability. Recommendations on other issues such as examination type, strategy and quality are also made.

Footnotes

  • Funding: Supported by an unrestricted educational grant from Allergan, Inc and Canadian Institutes of Health Research (MOP-11357).

  • Competing interests: BCC is or has been a consultant for Allergan, Mimetogen, Pfizer and QLT, and has received research support from Alcon, Carl Zeiss Meditec, Heidelberg Engineering, Pfizer and Welch Allyn. DFGH is or has been a consultant for Allergan, Carl Zeiss Meditec and Pfizer, and has received research support from Allergan, Carl Zeiss Meditech, Heidelberg Engineering, Optovue, Pfizer, Reichert and Santen. FJG has been reimbursed by Alcon, Allergan, Carl Zeiss Meditec and Pfizer for attending conferences and running educational programmes. BB is a consultant for Carl Zeiss Meditec and received travel support from Allergan and research funding from Carl Zeiss Meditec. ACV has been a consultant, received honoraria or teaching funding from Alcon, Allergan, Merck Sharpe Dohme and Pfizer, and is a developer of PROGRESSOR, a commercially available software package for visual field analysis. AH is or has been a consultant for Alcon Allergan, Carl Zeiss Meditec and Pfizer, and has received research support from Alcon, Allergan, Carl Zeiss Meditec and Santen.

Responses to this article

  • Authors' Reply
    • Balwantray C Chauhan,
    • David F. Garway-Heath, Francisco J. Goñi, Luca Rossetti, Boel Bengtsson, Ananth C Viswanathan, and Anders Heijl
    Br J Ophthalmol published online August 7, 2009
  • Is a field every 4 month a significant improvement over a field every 6 months?
    • Albert Alm
    Br J Ophthalmol published online August 7, 2009
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