June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Resilience of area-modulated perimetric stimuli to increased intraocular straylight
Author Affiliations & Notes
  • Tony Redmond
    School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
  • Lindsay Rountree
    School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
  • Roger S Anderson
    Optometry and Vision Science Research Group, School of Biomedical Sciences, Ulster University, Coleraine, N. Ireland, 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
  • Padraig Joseph Mulholland
    Optometry and Vision Science Research Group, School of Biomedical Sciences, Ulster University, Coleraine, N. Ireland, 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   Tony Redmond, Heidelberg Engineering (F); Lindsay Rountree, None; Roger Anderson, Heidelberg Engineering (R); Padraig Mulholland, Heidelberg Engineering (R)
  • Footnotes
    Support  Research fellowship (TR) and postgraduate scholarship (LR), awarded by the College of Optometrists
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 2856. doi:
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      Tony Redmond, Lindsay Rountree, Roger S Anderson, Padraig Joseph Mulholland; Resilience of area-modulated perimetric stimuli to increased intraocular straylight. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2856.

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

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Abstract

Purpose : To compare, in a cross-sectional prospective study, the resilience to increased intraocular straylight (IOS) of four energy modulation stimuli designed to probe changes in spatial summation in glaucoma.

Methods : Threshold (ΔE) was measured at 18 visual field locations in one eye of three young, healthy, psychophysically-experienced observers with normal media [age: 25, 31, 33 years], using four different energy modulation stimuli, each under four different levels of IOS. Stimuli were: A - fixed contrast (ΔI: 0.5, starting within Ricco’s area), varying in area; C1 - fixed area (0.02 deg2, within Ricco’s area), varying in contrast; AC - varying in both area and contrast simultaneously (starting within Ricco’s area); C2 - fixed area (0.15 deg2), equivalent to Goldmann III, varying in contrast. Step sizes (energy; luminance x area x duration) were equivalent for each stimulus. IOS was measured with an Oculus C-Quant (Oculus, Wetzlar, Germany) for each participant with each of three filters of increasing white opacity (filters 1, 3, and 5, LEE filters, Andover, UK), and with no filter (baseline), in a randomised order. Stimulus type and filters were randomised between all threshold tests. Mean visual field threshold was calculated for each participant and between participants, and plotted as a function of IOS.

Results : Mean IOS at baseline was 1.2 log(s). Filter 5 (greatest opacity) gave a mean IOS of 2.0 log(s). Simulated ages, calculated from normative IOS values (van den Berg et al, Am J Ophthalmol, 2007;144(3):358-63), are given in Fig.1. An increase in mean ΔE with increasing IOS was found for all stimuli, but was greatest for C1 and C2 stimuli, particularly with low/moderate levels of IOS (Fig.1). Mean ΔE for A and AC stimuli, were significantly lower than those for C1 and C2 stimuli with filters 1 and 3 (all p<0.05). The smallest increase in ΔE, and greatest resilience to moderate increases in IOS was found for stimuli in which area was modulated (A and AC). The overall effect persisted in individual participants’ data.

Conclusions : Area-modulated perimetric stimuli showed greater resilience to increased IOS, compared to conventional perimetric stimuli of fixed area, modulating in contrast, at least over the normal range of IOS expected across the typical human lifespan.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Mean ΔE for all observers as a function of IOS. The highest straylight values may be considered representative of significant cataract.

Mean ΔE for all observers as a function of IOS. The highest straylight values may be considered representative of significant cataract.

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