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PubMed1978

Flicker fusion thresholds of red-green dichromats.

Measurements of the relative energies required for critical flicker fusion (CFF) at each of 14 wavelengths were obtained in normal, protanopic, and deuteranopic observers. Normals required more energy beyond 580 nm in going from 30 to 40 flashes per second than protanopes or deuteranopes. This suggests an adaptational collapse of the red-sensitive mechanism of normals which is not present in the red cones of deuteranopes or the green cones of protanopes over the same intensity range.

Color Vision Defects↗
PubMed2000

The relationship between critical flicker fusion frequency (CFFF) and temperamental characteristics.

The analysis in this paper was based on data obtained from 80 male participants, aged 29-65. Critical Flicker Fusion Frequency (CFFF) was measured using the Flicker Test. The Formal Characteristics of Behaviour Temperament Inventory (FCB-TI) by Strelau and Zawadzki (1993) was used for temperamental characteristics. The results of statistical analysis did not confirm a hypothesis about the correlation between CFFF level and 3 temperamental characteristics. There were no immediate relationships among those variables. Correlation was observed when the CFFF coefficient of variance, instead of average CFFF values, was taken into account, especially in the case of a division into 2 groups of participants, "reckless" and "unsure." It could be interesting to check in the future a hypothesis about the stability of selected types of reactions.

Adult↗
PubMed1983

Age differences in effects on blood pressure, flicker fusion frequency, salivation and pharmacokinetics of single oral doses of dothiepin and amitriptyline.

Blood pressure, critical flicker fusion frequency (CFF), salivary flow rate and pharmacokinetics were compared in 7 young healthy volunteers (average age: 22.7 years) and in 7 elderly healthy volunteers (average age: 70.6 years) after single oral doses of the antidepressants dothiepin (DP) 25 mg and amitriptyline (AMP) 25 mg. Systolic blood pressure fell further and the reduction lasted longer in the elderly than in the young after both drugs. The decrease in CFF after AMP 25 mg, and the reduction in salivary flow rate after either DP 25 mg or AMP 25 mg were larger in the elderly than in the young. Plasma levels, T1/2 and Cl of both drugs in the elderly were also higher, longer and smaller, respectively, in the elderly. Clearance was found to be reduced in the elderly. More cautions dosage regimens of these drug should be considered for elderly patients.

Adult↗
PubMedDate not supplied

[The effect of a monotonous repetitive task on flicker fusion and subjective feelings].

The effects of a uniform repetitive and of an activating task on critical flicker fusion (cff) and subjective feelings were measured on 15 subjects under laboratory conditions. With the uniform repetitive task the cff decreased significantly and the subjective feelings showed marked changes. With the activating task we could determine changes neither for cff nor for subjective feelings (except factor "subjective recovery").

Boredom↗
PubMed1975

Double branched flicker fusion curves from the all-rod skate retina.

Electrical responses from the skate retina will only follow flicker up to frequencies of 5 hertz when intensities are below rod saturation. At greater luminances, the eye responds to rates as high as 30 hertz. As a result, a plot of critical flicker fusion as a function of intensity is a double branched curve. It seems that prolonged stimulation of skate rods, at high intensities, permits them to change their temporal response characteristics so that they follow high frequencies much as cones do in the duplex retina.

Animals↗
PubMed2005

Longitudinal changes in critical flicker fusion frequency: an indicator of human workload.

The aim of the study was to verify a hypothesis that critical flicker fusion frequency (CFFF) is season-related because of changes in the intensity and duration of sunlight. CFFF has a wide application in different fields, generally as an indicator of human workload. Therefore, confirmation of previous observations that CFFF is subject to a seasonal rhythm could make theoretical as well as practical sense. The analysis was based on data obtained from 23 male participants, aged 28-60 years. The study lasted 12 months. CFFF was measured with the flicker test. The results of statistical analysis indicate that CFFF changes over time. There are two forms of those changes: a linear trend and oscillations around the trend. Moreover, individual differences in the longitudinal course of CFFF (in trends as well as in oscillations) are observed. The conclusion is that CFFF is subject to longitudinal changes, whose pattern depends on individual differences. Additionally, the individual character of the CFFF changes over time allow the assumption that sunlight is probably not as significant a factor as expected, one that can modify the hypothetical pattern of season-related CFFF fluctuation. The obtained results are important for the methodology of experiments with CFFF and for the interpretation of the results of the flicker test.

Adult↗
PubMed1998

[Critical (foveal) flicker fusion frequency (CFF) is helpful in differential diagnosis of organic lesions from orthoptic amblyopias].

PURPOSE: To measure critical (foveal) flicker fusion frequencies (CFF) in normal eyes, unilateral maculopathies and neuropathies and in orthoptic amblyopias. METHODS: A newly developed apparatus (4F) with LED's measured subjective foveal CFF by ascending and descending mode in a group of normals and patients. RESULTS: The apparatus (4F) measures temporal resolution. Foveal CFF ist more reduced in neuropathies than in maculopathies. In contrast, CFF in amblyopic eyes is hardly reduced, in most cases equal or better than in the dominant fellow eye. This is independent from the visual acuity of the amblyopic eye. CONCLUSION: CFF testing is useful in the evaluation of unexplained (unilateral) reduction of visual acuity. A dissociation between visual acuity and CFF (within normal range) is present in cases of amblyopia.

Amblyopia↗
PubMed1975

A comment on critical flicker fusion as an objective measure of alcohol tolerance by alcoholics.

A previous paper reported that for alcoholics the threshold for critical flicker fusion is relatively unchanged by the ingestion of alcohol and concluded therefore that the technique could be used to indicate tolerance to alcohol. The present paper urges caution in this respect owing to the evidence that clinical subjects frequently adopt more cautious response strategies than normals with psychophysical procedures. Reports are also reviewed which indicate that alcoholics consume more tobacco than normals and that the stimulant effect of nicotine could antagonize the depressant effect of alcohol on CFF.

Alcoholism↗
PubMed1988

Information processing, critical flicker fusion threshold and benzodiazepines: results and speculations.

There is evidence to suggest that the rate of information processing, as measured by the critical flicker fusion threshold (CFFT), is slower following some benzodiazepines than others. Changes in CFFT brought about by benzodiazepine administration are usually, but not always, correlated with changes in other measures of cognitive performance and memory. However, the drug-induced changes in information processing and memory cannot be fully explained by simple postulates regarding alterations in the overall level of CNS arousal. Results from a series of studies of the effect of benzodiazepines on measures of CFFT and memory will be reviewed and the utility of CFFT in evaluating the amnesic or mnemonic potential of CNS-active drugs will be assessed.

Anti-Anxiety Agents↗
PubMed1992

Foveal flicker-fusion frequencies: a simple, new apparatus (4F).

While spatial resolution may be easily assessed with contrast-sensitivity frequency (CSF) data, determination of foveal flicker-fusion frequency (4F) is a simple method of providing the ophthalmic practitioner with accurate information about temporal resolution. The authors describe a simple apparatus that controls luminance, light intensity, light intervals, stimulus size, homogeneity of background illumination, and binocular gaze, especially when using two wavelengths, allowing an increased number of applications with reliable and comparable results. It may prove to be a useful tool for screening, clinical and subclinical assessment, and for evaluating visual acuity, also during follow-up.

Adolescent↗
PubMed1981

Critical flicker fusion (CFF) test for sedative effect of antidepressants.

It is important to know in which direction and to what extent a drug affects cerebral arousal. Critical flicker fusion (CFF) is a most reliable method for measuring this particular quality of various drugs. A semi-automatic apparatus was used under standardized conditions, and double-blind technique was employed. Only acute experiments are described here. Dose-effect relationship can be demonstrated. The effect on cerebral arousal varies greatly from one antidepressant to another. Amitriptyline and doxepin were found to exert strong sedative effect, and amitriptyline-N-oxide an intermediate one, while imipramine and imipramine-N-oxide lacked this quality. Nomifensine in large doses has a significant stimulant action. Zimelidine in a low dose (75 mg) slightly, but significantly, lowered the CFF level, but at a dose of 150 mg no significant effect was obtained. At the doses 225 and 300 mg a slight increase was seen (about 2%). Various aspects of the findings are discussed in the paper.

Adult↗
PubMed1996

Accumulation of VDT work-related visual fatigue assessed by visual evoked potential, near point distance and critical flicker fusion.

To confirm daily accumulation of visual fatigue induced by work with visual display terminals (VDT), visual evoked potential (VEP), near point distance (NPD) and critical flicker fusion (CFF) were measured in three VDT workers and three sex- and age-matched controls (non-VDT workers) in the morning, noontime and evening for five consecutive days (Monday to Friday), totally 15 times per subject. The workers had been engaged in wireless handling operation, with VDTs, of an unmanned power shovel (Worker 1), an unmanned 78-ton dump truck (Worker 2) and mobile monitor-cameras (Worker 3), for 10 months. Their working hours were about 6.5 hours per day; but, the Worker 2 could take a 10-minute recess (a period without VDT work) per about 30 minutes during working hours. Significant daily variations in the VEP latency, NPD and CFF were found in the Worker 1 or Worker 3 despite the absence of any significant daily or diurnal variations in the non-VDT workers; the trends in the variations were getting worse from Monday to Friday. The NPD in the VDT workers was significantly longer than that in each of the matched controls; also, the CFF in the Workers 1 and 3 was significantly depressed. The changes in the VEP latency from morning to noontime and in the NPD and CFF from noontime to evening were significantly larger in the VDT worker than in the matched control. These findings suggest that VDT work probably affects visual function assessed by the VEP, NPD and CFF. Visual fatigue due to long-term VDT work may tend to be accumulated day by day.

Adult↗