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J. G. Flanagan, J. W. Cassidy; The Heidelberg Edge Perimeter: A New Test of Visual Function. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1098.
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© ARVO (1962-2015); The Authors (2016-present)
To introduce the design principles, scientific rationale and preliminary clinical data for the Heidelberg Edge Perimeter (HEP).
HEP uses flicker defined form (FDF) to generate the stimuli used to evaluate the visual field. FDF was generated by flickering random dots of 0.34° at 15Hz against a mean luminance background (50cdm-2). Dots within the 5° stimulus were flickered in counterphase to background dots. The random dot background had a density of 3.5 dots per degree. A preliminary normal database of 100 volunteers was used to establish preliminary confidence intervals to define normality and limits for threshold estimation algorithms. Test-retest characteristics were established using 30 patients with glaucoma, and compared to SITA-SAP and Matrix. Combination Structure-Function Maps were generated using HEP and the HRT. Clinical trials will be presented that establish the effect of optical blur, random dot density and organization, temporal frequency and stimulus size.
HEP performance improved with higher contrast, a greater random dot density, greater background element organization and mid-peripheral viewing. It is robust to < 6D of optical blur and is dependent on target area rather than contour. The coefficient of repeatability was 6.86dB for FDF, 7.82dB for SITA-SAP and 10.29dB for the Matrix.
The Heidelberg Edge Perimeter used flicker defined form, a magnocellularly driven illusion, to efficiently measure the central visual field. Preliminary clinical trials indicate: i. Good test-retest characteristics, ii. Ability to detect early glaucoma and iii. Deeper and larger defects (frequently) than standard automated perimetry.
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