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The Flicker Generator is an exceptional product with the simplicity to be used as a demonstration device in the teaching

environment, but also the sophistication to be used as an instrument in rigorous research investigations. The device is

able to demonstrate square wave flicker at a 50% duty cycle. With a large range of possible flicker rates, intensity, colors,

and contrasts, it can used to test critical flicker frequency fusion thresholds in both in central and peripheral vision.

The Flicker Generator is capable of performing the following functions;

frequency of the modulation;

red and blue colors;

the depth of modulation while maintaining constant average illumination intensity (contrast);

intensity of illumination;

the position on the retina at which the stimulation occurs

Observer Unit

Stimulus Light approximately 90 lumens , with 1.5 inch diffuser

Colors red 625 nm

blue 467.5 nm

Peripheral Light 15 degrees offset at a subject distance of 57-60 centimeters

Size 6.29 (15.9) x 6.29 (15.9), 3.56 ( 9) depth

Power supply 110 VAC or 9 volt battery

Demonstrator Unit

Rate 0 to 100 Hertz 1% accuracy and resolution

Luminance 1 to 100 % 1% resolution

Contrast 1 to 100% 1% accuracy and resolution

Size 7.5 (190.5) x 4.1(101.0), 1.2 (32.6) depth

The Flicker generator is capable of demonstrating the following;

critical flicker frequency (CFF)
Flicker fusion is the visual phenomenon in which a repetitively presented stimulus (the flickering stimulus) appears as a single continuous stimulus

Ferry-Porter Law
The Ferry/Porter Law states that critical flicker frequency will increase proportionally as a function of the logarithm of the stimulus intensity.

Bloch's Law
Bloch's law states that for durations below the critical flicker frequency, perceived contrast is linearly determined by stimulus contrast or intensity as a function of stimulus duration

Granit/Harper Law
The Granit/harper law states that the critical flicker frequency increases linearly with the logarithm of the stimulus area (for use with the aperture)

Peripheral fixation light

10-15 degrees at a distance of 60cm to the side, to display the difference in sensitivity of rods, cones

Color selection of red or blue

possibly related to Age-Related Macular Degeneration and Low Visual Acuity

References include;

Intermittent Stimulation By Light www.ncbi.nlm.nih.gov/pmc/articles/PMC2141276/pdf/251.pdf

Effects of Repetitive Tasks on Critical Fusion Frequency www.tandfonline.com/doi/abs/10.1080/00140137908024622

Wikipedia: Flicker Fusion Threshold https://en.wikipedia.org/wiki/Flicker_fusion_threshold

ScholarPedia: www.scholarpedia.org/article/User:Eugene_M_Izhikevich/Proposed/Flicker_Fusion

Assessment of Visual Function in Patients With Age-Related Macular Degeneration and Low Visual Acuity
Marguerite F. Alexander, RN; Maureen G. Maguire, PhD; Thomas M. Lietman; Judith R. Snyder; Michael J. Elman, MD; Stuart L. Fine, MD
Arch Ophthalmol. 1988;106(11):1543-1547. doi:10.1001/archopht.1988.01060140711040.

A Differential Color flicker test for detecting acquired color vision impairment in multiple sclerosis and diabetic neuropathy

Bruno Gregori, Odysseas Papazacharadis, Alfonsa Farrugia, Neri Accornero