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Y.-H. Ho, K. Esmonde, J. G. Flanagan; The Effect of Dioptric Blur on Visual Field Asymmetry Using Flicker Defined Form Perimetry. Invest. Ophthalmol. Vis. Sci. 2010;51(13):5516.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the effects of dioptric blur on retinal sensitivity for Flicker Defined Form (FDF) and its effect on visual field asymmetry within hemifield and by eccentricity in normal subjects using the Heidelberg Edge Perimeter (HEP).
Ten normal subjects ( age: 24.3 ± 3.3, gender ratio: 1:1) were recruited for two visits to perform ten sets of custom visual field testing, in random order, using 0,1,2,3,4,5,6,8,10,12 dioptres of positive blur, 0 DS being the corrected, emmetropic condition. FDF stimuli (5º diameter) were generated using the Heidelberg Edge Perimeter (HEP) and presented at fixation (0), 3*3, 9*9, 15*15 degree eccentricity along the minor meridians of four quadrants within the visual field. The retinal sensitivity was determined using a Baysian, adapted staircase method.
The effect of blur was significantly different between the superior and inferior hemifield (p<0.001). FDF stimuli were resistant to +10 DS at the fovea and +6 DS at 3 and 9, and +4DS at 15. There was a significant effect of eccentricity (p<0.001), with 15º being significantly different from fixation, 3º and 9º eccentricity (p<0.001).
The FDF stimulus was relatively resistant to positive dioptric blur, compared to contrast sensitivity based stimuli, such as that used in Standard Automated Perimetry. There was a significant effect of both eccentricity and hemifield.
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