Critical Fusion Frequency in the Central Visual Field

Abstract

The critical fusion frequency (CFF) was measured across the central visual field. Stimulus parameters were adjusted to ensure an increase in CFF at the fovea. Comparison was made between the foveal and extra-foveal CFF values. The study showed that, while the CFF may be highest at the fovea when the CFF values are generally low, stimulus parameter changes that increase the CFF result in a greater increase extra-foveally. Ultimately, then, the CFF maximum shifts from the fovea to an extra-foveal area. Under the experimental conditions used in the study, the maximum occurred approximately 10 degrees from fixation.

Meridional differences in temporal response characteristics

“…The C F F profiles for the 0.431 and 1.724 degree stimuli (averaged over all stimulus luminances) in the inferior nasal quadrant were shown to decrease significantly faster with increasing eccentricity than in any of the remaining visual field quadrants, all of which were shown to be statistically similar. Figure 3 shows that the results of this study fall into category one as described by Douthwaite et al (1985), which comprised studies reporting maximum (CFF at the fovea. This finding may relate, at least partly, to a hypothesis proposed by Tyler (1987) that regions of greater cone density may correspond to regions of greater modulation sensitivity resulting in a consequential increase in CFF.…”

“…It is now well established that a large variety of stimulus parameters influence the CFF, including stimulus wavelength, intensity, angular subtense, background luminance, surround size, light/dark ratio ( LDR), and contrast (for reviews see Landis, 1954;Wolfe and Schraffa, 1964;Brown, 1965;Tate and Lynn, 1977;Shickman, 1981;Douthwaite et ul., 1985). Douthwaite et al ( 1985) noted that studies reporting the relationship between C F F and retinal eccentricity could be divided into two categories. Douthwaite et al ( 1985) noted that studies reporting the relationship between C F F and retinal eccentricity could be divided into two categories.…”

Loss of visual function associated with microalbuminuria in diabetes mellitus

“…This was repeated and the average CFF value was calculated as a baseline measurement. A 2 sec presentation of the flickering light was then used as this timespan prevents local adaptation to flicker (Douthwaite et al 1985). The frequency was altered using a manual staircase procedure around the baseline value until a consistent CFF value was obtained.…”

Meridional differences in temporal response characteristics

“…It is now well established that a large variety of stimulus parameters influence the CFF, including stimulus wavelength, intensity, angular subtense, background luminance, surround size, light/dark ratio ( LDR), and contrast (for reviews see Landis, 1954;Wolfe and Schraffa, 1964;Brown, 1965;Tate and Lynn, 1977;Shickman, 1981;Douthwaite et ul., 1985). The CFF is also known to vary with retinal eccentricity (Alpern and Spencer, 1953;Hartmann, Lachenmayr and Brettell, 1979;Fukuda, 1979;Douthwaite et al, 1985;Skrandies, 1985;Yasuma, Miyakawa and Yamazaki, 1986;Tyler, 1987;Rovamo and Raninen, 1988) yet the characteristics of this variation are still a matter of some contention. Douthwaite et al ( 1985) noted that studies reporting the relationship between C F F and retinal eccentricity could be divided into two categories.…”

“…The CFF is also known to vary with retinal eccentricity (Alpern and Spencer, 1953;Hartmann, Lachenmayr and Brettell, 1979;Fukuda, 1979;Douthwaite et al, 1985;Skrandies, 1985;Yasuma, Miyakawa and Yamazaki, 1986;Tyler, 1987;Rovamo and Raninen, 1988) yet the characteristics of this variation are still a matter of some contention. Douthwaite et al ( 1985) noted that studies reporting the relationship between C F F and retinal eccentricity could be divided into two categories. Those reporting a maximum CFF at the fovea (Creed and Ruch, 1932;Ross, 1936;Fukuda, 1979) and those reporting a maximum C F F at some extra-foveal locus (Phillips, 1933;Ridell, 1936;Hylkema, 1942;Miles, 1950;Haycock, 1954;Lovekin and Chandler, 1959;Campbell and Ritter, 1959;Hartmann, Lachenmayr and Brettell, 1979).…”