September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Test-Retest Repeatability of Microperimetry at the Central and Border Regions of Remaining Retina in Choroideremia
Author Affiliations & Notes
  • Ioannis Dimopoulos
    Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
  • Calvin Tseng
    Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
  • Ian M MacDonald
    Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
  • Footnotes
    Commercial Relationships   Ioannis Dimopoulos, None; Calvin Tseng, None; Ian MacDonald, None
  • Footnotes
    Support  AIHS CRIO Team Grant, CIHR
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 627. doi:
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    • Get Citation

      Ioannis Dimopoulos, Calvin Tseng, Ian M MacDonald; Test-Retest Repeatability of Microperimetry at the Central and Border Regions of Remaining Retina in Choroideremia. Invest. Ophthalmol. Vis. Sci. 2016;57(12):627.

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

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Abstract

Purpose : Choroideremia (CHM) is a rare X-linked retinal degenerative disease characterized by chorioretinal atrophy, with complete blindness occurring later in life. Visual acuity remains the most widely used functional outcome measure in current CHM clinical trials. Fundus-tracked perimetry (microperimetry-MP) has emerged as a new method of assessing progression of functional vision loss before changes in visual acuity ensue. This study assesses the reliability of microperimetry as an outcome measure in clinical trials.

Methods : 24 eyes from 13 CHM patients and 7 eyes from age-matched controls were included. Subjects performed 2 MP tests (MAIA; CenterVue, Centervue, Padova, Italy) within the same session using a standard 37 stimuli grid pattern (size: Goldmann III, duration: 200ms, 4-2 staircase strategy). Retest variability was assessed by computing the coefficients of repeatability (CoR) for mean (MS) and point-wise sensitivity (PWS). For choroideremia patients, PWS repeatability was separately analyzed for central loci and loci at the border of degeneration. To determine the precise location of each tested sensitivity locus, microperimetry SLO images were aligned and registered to fundus autofluorescence images (Spectralis SD-OCT; Heidelberg Engineering, Germany) using commercial image editing program (GIMP v.2.8.14).

Results : CoR for MS were not significantly different between control and CHM eyes (1.51 dB vs 1.33dB, p=0.85). CoR for PWS were significantly greater in CHM eyes than in control eyes (8.7 dB vs 4.5 dB, p<0.001). Regional PWS repeatability was seperately assesed in n=192 points at the border of degeneration (within 1° temporal to the margin of RPE atrophy) and n=160 points within the central “healthier” retina. Repeatability of loci at the border of degeneration was found to be significantly greater compared to loci within the central retina (10.68 dB vs 4.74 dB, p<0.001).

Conclusions : MP testing shows high test-retest variation at the border of degeneration in CHM. These findings preclude the use of a single estimate of repeatability for MP PWS in CHM. Although providing limited spatial information, global indices, such as MS, show higher reliability as outcome measures in CHM clinical trials.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

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