July 2019
Volume 60, Issue 9
Open Access
ARVO Annual Meeting Abstract  |   July 2019
A new perimetry thresholding algorithm with size-modulated stimuli reduces variability by half in damaged regions of the visual field compared to SITA Standard
Author Affiliations & Notes
  • David F Garway-Heath
    National Institute for Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
  • Marco A. Miranda
    National Institute for Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
  • Haogang Zhu
    National Institute for Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
    School of Computer Science, Beihang University, Beijing, China
  • Pádraig J. Mulholland
    National Institute for Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
    Optometry and Vision Science Research Group, Ulster University, Coleraine, United Kingdom
  • Bledi Petriti
    National Institute for Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
  • Carol Bronze
    National Institute for Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
  • David P Crabb
    Division of Optometry and Visual Sciences, City University London, London, United Kingdom
  • Roger Anderson
    Optometry and Vision Science Research Group, Ulster University, Coleraine, United Kingdom
    National Institute for Health Research (NIHR) Biomedical Research Centre, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
  • Footnotes
    Commercial Relationships   David Garway-Heath, Carl Zeiss Meditec (C), Carl Zeiss Meditec (F), Centervue (C), Centervue (F), Heidelberg Engineering (R), Psychophysical test: MMDT (P), Thresholding algorithm: T4 (P); Marco Miranda, Thresholding algorithm: T4 (P); Haogang Zhu, Psychophysical test: MMDT (P), Thresholding algorithm: T4 (P); Pádraig Mulholland, Heidelberg Engineering (R); Bledi Petriti, None; Carol Bronze, None; David Crabb, Centervue (C), Psychophysical test: MMDT (P), Thresholding algorithm: T4 (P); Roger Anderson, None
  • Footnotes
    Support  NIHR Invention for Innovation (i4i) Programme: II-LA-0813-20004
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 2859. doi:https://doi.org/
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      David F Garway-Heath, Marco A. Miranda, Haogang Zhu, Pádraig J. Mulholland, Bledi Petriti, Carol Bronze, David P Crabb, Roger Anderson; A new perimetry thresholding algorithm with size-modulated stimuli reduces variability by half in damaged regions of the visual field compared to SITA Standard. Invest. Ophthalmol. Vis. Sci. 2019;60(9):2859. doi: https://doi.org/.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose : Identifying glaucomatous progression is challenging because of considerable variability in visual field (VF) test results. Reducing variability would reduce the time and/or number of VFs required to measure progression, improving clinical care and saving resources. Hypothesis: the precision (test retest variability) of a new thresholding algorithm (trail traced threshold test (T4; Zhu 2018; 59(9): ARVO E-abstract 5114 #5114) is better than that of the Humphrey Field Analyzer SITA Standard test (Carl Zeiss Meditec) for a similar test time. Interim results were presented Petriti 2018; 59(9): ARVO E-abstract 5115.

Methods : The T4 algorithm models a probability of seeing (PoS) curve at each location with a reversed cumulative normal distribution. The likelihood of response is a weighted binomial distribution in which the weights of neighbour locations are defined according to anatomical proximity; each response to a stimulus updates the PoS parameters at its own location and those of neighbouring locations. The algorithm was implemented on an EIZO GS521 monochromatic monitor. Stimuli were i) circular spot of light modulated in size at constant contrast (27dB) (T4sm) and ii) oscillating bars (T4mmdt). 86 clinically stable glaucoma patients with previous reliable VFs (median [IQR] age 69 [62-73] years and mean deviation -4.54 [-0.90 – -11.26] dB) underwent testing in one eye with SITA Standard, T4sm and T4mmdt in a randomized order; tests were repeated on the same day.

Results : SITA and T4sm are presented. Mean (SD) test time: SITA 5.51 (1.03) mins, T4sm 5.17 (0.52) mins. Figure 1: SD of test retest differences against location sensitivity. Variability (absolute test retest differences) is similar above 26dB threshold sensitivity (SITA 1.48dB (SD 0.22), T4sm 1.33dB (SD 0.56); p = 0.02) and reduced by half below 26dB (SITA 5.77dB (SD 2.53), T4sm 2.89dB (SD 1.02); p< 0.001). Figure 2: Bland-Altman plots of reproducibility (all locations, all subjects), left SITA Standard, right T4sm. The heteroscedasticity of test retest differences is considerably reduced.

Conclusions : The precision of T4sm is markedly better than SITA Standard in damaged locations of the VF for a similar test time. Improved precision and reduced heteroscedasticity should make a meaningful clinical impact, improving the detection and quantification of glaucoma progression.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

 

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×