Because fusion frequency
is also correlated with latitude, southern populations would be expected to have a bigger size than northern ones.
At the second stage ophthalmological status (acuity of vision and refraction) was estimated as well as functional (critical flicker fusion frequency -CFFF) electrophysiological (electrosensitivity threshold -EST; electrolabilityEL), phychophysiological (channel capacity- CC, visual information volume -VIV, visual information speed -VIS, efficiency of visual information analysis -EVIA) investigations were carried out [4, 5].
Negative relation between critical flicker fusion frequency and such parameters of visual perception as channel capacity of visual system and visual information processing may seem to be paradoxical because according to the canon of sensor physiology, the higher is the frequency characteristics of the communication channel, the higher its channel capacity .
Most humans are unable to perceive flicker in light above 60 Hz, but there still remain measurable biological effects above the critical fusion frequency
To address this issue, electro-retinography was used to measure the changes in retinal light sensitivity, flicker fusion frequency, and spectral sensitivity in black rockfish (Sebastes melanops) subjected to rapid decompression (from 4 atmospheres absolute [ATA] to 1 ATA) and Pacific halibut (Hippoglossus stenolepis) exposed to 15 minutes of simulated sunlight.
Three separate procedures were conducted to test for treatment effects on visual function: responses to increasing light intensities (V-log I response curves), flicker fusion frequency, and spectral sensitivity.
plebs eye was quantified using two methods: (1) response waveform dynamics, and (2) flicker fusion frequency.
Flicker fusion frequency experiments involved presenting the eye with square pulses from a flickering stimulus light, generated by cycling a computer-controlled electromagnetic shutter in the light path, for 2 s at a given frequency with a 50:50 light/dark ratio, and recording the corresponding ERG (see Frank, 1999).
The influence of age on the fusion frequency
When measured by means of the flicker fusion frequency
(FFF), this effect is present only when normal eye movements are permitted.
However, Moeller and Case (1995) measured the critical flicker fusion frequency
at threshold light intensities, which is difficult to compare between species because (1) the threshold sensitivity of a crustacean eye measured using the ERG technique varies considerably from preparation to preparation (pers.
The flicker fusion frequency
was measured with 10 ms flashes in dark adapted crabs, as well as in crabs adapted to and tested in 11.