Appearance of the Frequency Doubling Stimulus in Normal Subjects and Patients with Glaucoma

Abstract

When instructed as for clinical testing, subjects respond to the presence of the structure of the grating, and perceive the FDT stimulus to have a spatial frequency greater than its true spatial frequency. These findings were consistent across both normal observers and those with glaucoma, at both central and eccentric test locations.

Rarebit and frequency‐doubling technology perimetry in children and young adults

“…Frequency‐doubling technology perimetry was developed in the assumption that it would measure the integrity of a particular subgroup of retinal ganglion cells (Anderson & O'Brian 1997). However, this assumption has been questioned (Anderson & Johnson 2002; White et al 2002), and the method may instead be measuring grating detection or contrast sensitivity rather than spatial frequency doubling (McKendrick et al 2003). Children are supposed to reach adult‐like levels of contrast sensitivity (measured with contrast sensitivity distance charts) at 7 years of age, but the variability is rather high (Scharre et al 1990).…”

Frequency-Doubling Illusion under Scotopic Illumination and in Peripheral Vision

“…1999; 40:ARVO Abstract 42). 17,18,21 Sufficient evidence (including from this laboratory; not reported here) now shows that under photopic conditions, apparent spatial frequency of a grating gradually increases before it doubles at approximately 8 to 12 Hz. We report similar results in this study under scotopic illumination conditions.…”

“…Before entertaining thoughts on the development of a scotopic FDI-based clinical test for glaucoma, it is necessary to determine how scotopic FDI is perceived at central and peripheral retinal locations and how this relates to the FDI elicited under photopic conditions. In the photopic case, although early studies reported perception of the FDI only within 2°e ccentricity, 17 McKendrick 18 and James 19 later confirmed that the FDI is perceived at retinal eccentricities up to 20°. The second aim of this article is thus to characterize and compare the FDI at different retinal eccentricities under photopic and scotopic conditions.…”

Spatial Frequency Shifts From Counterphase Flicker and From Simultaneous Contrast

“…However, the increase was far less than doubling: Average increase in apparent SF was 39% for 1.2 cpd and 29% for 2 cpd (increase was greater for 1.2 cpd than for 2 cpd, t 9  = 2.89, p  < .05, which is consistent with the literature; e.g., Parker, 1983). Although for low spatial frequency conditions (<1 cpd) frequency doubling has been reported up to 20 deg eccentricity (McKendrick, Anderson, Johnson, & Fortune, 2003; Vallam, Pataridis, & Metha, 2007), flicker-induced apparent SF increase is greater in central vision for relatively high spatial frequencies (Parker, 1983). Therefore, this smaller effect than doubling in our experiment was not unexpected.…”