NanoMeasure Vision Products
developing products to enhance and innovate the measurement capabilities of science
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