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Meshary Alrumizan, Simon P Harding, Paul Knox; Relationships between handheld Radial Shape Discrimination (hRSD) and Contour Integration Macular Perimetry (CIMP) testing. Invest. Ophthalmol. Vis. Sci. 2019;60(9):4384.
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© ARVO (1962-2015); The Authors (2016-present)
The hRSD test has shown promise for the earlier detection of macular pathology (Pitrelli Vasquez et al, 2018, PLOS One 13:e0207342). Wang and Mitchel (2013, IOVS 54:5019) described CIMP as a means of testing visual function outside the central macular subfield. We have investigated how the results of these two tests relate to each other and visual acuity (VA) in healthy participants.
CIMP stimuli consisted of four circular contour segments, each a 30° circular arc, evenly placed along the center of either the inner ring (iCIMP; presented on an iPhone 7) or outer ring (oCIMP; presented on an iPad) of the ETDRS macular grid. In each trial, one segment (the target that the participant had to touch) was distorted by radial modulation and the others were smooth. The stimulus duration was 0.25 sec. The hRSD test was run on both the iPhone and the iPad to compare the results. Healthy participants completed CIMP tests, the two hRSD tests, and tests of near and distance VA on both eyes in a single session.
Data were available from 40 participants (mean±SD age 33.18 ± 10.53 years; range 18 – 65; female/male, 15/25); right eye data were analysed. Mean near and distance VA were -0.04± 0.14 logMAR and -0.01± 0.14 logMAR respectively. hRSD test results differed statistically between the two devices (iPhone: -0.75 ± 0.14 logMAR; iPad: -0.70 ± 0.17 logMAR; paired t-test = 2.06; p<0.05). Mean iCIMP (-0.73 ± 0.27 logMAR) and oCIMP (-0.79 ± 0.10 logMAR) thresholds did not differ significantly (t=1.46; p=0.15) and were not correlated (r=0.25; p=0.12). iCIMP and the mean of the two hRSD thresholds did not significantly correlate (r= 0.152 p= 0.349) while oCIMP and hRSD threshold did (r= 0.380, p= 0.016). iCIMP was not correlated with near or distance VA while oCIMP correlated with both (near: r=0.42, p=0.007; distance: r=0.54, p<0.001).
CIMP and hRSD results are similar to previous reports. The difference in hRSD thresholds between devices, while statistically significant, is within the test-retest variability previously reported. Absent or low levels of correlation between tests may be consistent with different areas of central and paracentral macular vision being tested. The extent to which various macular pathologies differentially affect these different tests remains to be investigated.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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