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Binnie, C. D.; Korte, R. A. de; Wisman, T. (1979): Fluorescent lighting and epilepsy. In: Epilepsia, Jg. 20, H. 6,S. 725–727.Abstract Fluorescent tubes flash at twice the mains frequency (100 Hz in Europe). With

aging, 50-Hz brightness modulation appears. A survey of tubes used in our instituteshowed that 42% exhibited brightness modulation up to a depth of 20% oroccasionally 30%. The effects of fluorescent lighting on the EEGs of 20 patientswith photosensitive epilepsy have been studied. In no patient did the 100-Hz flickerof normally functioning tubes elicit paroxysmal activity. In 8 of 13 subjects sensitiveto 50 Hz, IPS paroxysmal discharges were evoked by 50-Hz brightness modulation,but only at modulation depths of 50% or more. It is concluded that as paroxysmalactivity could not be elicited by normally functioning tubes nor at those depths ofmodulation occurring in practice, fluorescent lighting is unlikely to present a hazardto photosensitive patients.

Schlagwörter Adolescent; Adult; Electroencephalography; Epilepsyetiology; Female; Humans;Lighting; Male

Chauhan, K.; Charman, W. N. (1996): Accommodation responses to flickering stimuli. In: Ophthalmic &physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists), Jg. 16, H. 5, S.391–408.Abstract It has been suggested that accommodation to visual display unit (VDU) symbols or

to stimuli lit by fluorescent tubes or similar temporally modulated light sources maybe less accurate due to flicker. Furthermore, if the microfluctuations ofaccommodation play a part in the control of steady-state accommodation, theeffects of stimulus flicker might affect the quality of this control. Experiments aredescribed in which monocular accommodation stimulus-response curves forsinusoidal grating stimuli (1.0, 5.3 and 8.9 c/deg) were measured under thefollowing conditions of temporal modulation: (1) square-wave on-off modulation togive spatial modulation varying between 0 and 37%; (2) sinusoidal modulation togive spatial modulation varying between 0 and 37%; (3) sinusoidal modulation togive spatial modulation varying between 16 and 32%; and (4) on-off modulation withvarying mark/space ratio. Temporal modulation frequencies were between 0.5 and7.8 Hz and above the critical fusion frequency (CFF) i.e., > or = 40 Hz. In general,the results suggest that while lower-frequency flicker may adversely affect theaccuracy and stability of the accommodation response, the latter are very littleaffected by flicker at frequencies > or = 40 Hz. Thus flicker from fluorescent lampsor VDUs is unlikely to cause systematic accommodation difficulties. The possiblerelevance of the results to theories which ascribe a role for the higher-frequency (>0.5 Hz) accommodative microfluctuations in the control of the response isconsidered.

Schlagwörter Accommodation, Ocularphysiology; Analysis of Variance; Humans; Lightadverseeffects; Vision Testsmethods

Eysel, U. T.; Burandt, U. (1984): Fluorescent tube light evokes flicker responses in visual neurons. In: Visionresearch, Jg. 24, H. 9, S. 943–948.Abstract Single neurons in the cat visual system respond distinctly to the temporal

information present in light from fluorescent tubes driven by 50 or 60 Hz alternatingcurrent. Despite the resulting flicker frequencies of 100 or 120 Hz all retinal andmost thalamic neurons show strong phase locking of the neuronal responses to themodulation of fluorescent tube light. Some retinal ganglion cells have not yetreached their critical flicker fusion frequency under such conditions. Though usuallybeyond perception, the frequency and depth of modulation of artificial light thusmight well play a role in biological light effects.

Schlagwörter Animals; Cats; Evoked Potentials, Visual; Flicker Fusionphysiology; GeniculateBodiesphysiology; Light; Lighting; Optic Nervephysiology; Photometry;Retinaphysiology; Retinal Ganglion Cellsphysiology

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Küller, R.; Laike, T. (1998): The impact of flicker from fluorescent lighting on well-being, performance andphysiological arousal. In: Ergonomics, Jg. 41, H. 4, S. 433–447.Abstract In working environments all over the world, fluorescent tubes are by far the

dominating light source. Still, there have been very few studies on the impact of thenon-visible flicker from fluorescent tubes. The purpose of the study was to comparethe impact on subjective well-being, performance and physiological arousal offluorescent light powered by conventional and high-frequency ballasts. Thirty-sevenhealthy males and females were subjected to either condition in a laboratory officeon two separate occasions with 1 week in between. Although the methodology wasquite extensive, only a few general effects were observed. However, when the lightwas powered by the conventional ballasts, individuals with high critical flicker fusionfrequency (CFF) responded with a pronounced attenuation of EEG alpha waves,and an increase in speed and decrease in accuracy of performance. These resultsmay be understood in terms of heightened arousal in the central nervous system inresponse to the pronounced light modulation caused by the conventional ballasts.In order to alleviate this potential stress source, it is recommended that fluorescentlighting be powered by electronic high-frequency ballasts of good quality.

Schlagwörter Adult; Analysis of Variance; Arousalphysiology; Electroencephalography;Environment; Female; Humans; Lighting; Male; Middle Aged; Occupational Health;Task Performance and Analysis; Workplace

Nuboer, J. F.; Coemans, M. A.; Vos, J. J. (1992): Artificial lighting in poultry houses: do hens perceive themodulation of fluorescent lamps as flicker. In: British poultry science, Jg. 33, H. 1, S. 123–133.Abstract 1. Many poultry houses are illuminated by fluorescent lamps which produce

discontinuous illumination with a frequency of either 100 or 120 Hz. 2. This studyinvestigated whether domestic fowls perceive this discontinuity as flicker by trainingtwo Leghorn hens to choose between a continuous and a discontinuous light, allother variables being identical. 3. The light-stimulus was either monochromatic with100% sinusoidal modulation or a fluorescent lamp whose modulation frequencycould be electrically adjusted. 4. Each (correct) choice for the discontinuous lightwas followed by a 5 Hz higher frequency, whereas an incorrect choice was followedby a 10 Hz lower frequency. 5. On the basis of this principle the animals themselvesestablished the highest perceivable frequency of the discontinuous light, called theCritical Fusion Frequency (CFF), that they could discriminate from continuous light.6. These frequencies typically depend on the stimulus intensity increasing withincreasing intensities, until a maximum value is reached. 7. Two factors limited themagnitudes of the CFF's that were recorded: the maximum stimulus intensitiesproduced and variability in the chicken's response ("behavioural noise"). In spite ofthese constraints 105 Hz was established as the maximum CFF. 8. On the basis ofextrapolation it is concluded that the direct light from fluorescent lamps driven by 50Hz alternating current is seen by the chicken as flickering. 9. The results justifylarge-scale comparison of behaviour and production in poultry houses that areilluminated either by low-frequency or by high-frequency fluorescent lamps.

Schlagwörter Animals; Chickensphysiology; Conditioning, Classical; Female; Fluorescence;Housing, Animal; Lighting; Microcomputers; Visual Perception

Sakai, Tsutomu; Calderone, Jack B.; Lewis, Geoffrey P.; Linberg, Kenneth A.; Fisher, Steven K.; Jacobs, GeraldH. (2003): Cone photoreceptor recovery after experimental detachment and reattachment: animmunocytochemical, morphological, and electrophysiological study. In: Investigative ophthalmology & visualscience, Jg. 44, H. 1, S. 416–425.Abstract PURPOSE: To compare the morphologic and functional recovery of the retina after

detachment and reattachment in an animal with a cone-dominant retina, the groundsquirrel. METHODS: Ground squirrel (Spermophilus beecheyi) retinas weredetached for 1 day and reattached for 7, 35, or 96 days (n = 2, each time point).Flicker ERGs were recorded 1 day after the detachment and at various times after

iLib08 - CitaviiLib08 - CitaviiLib08 - CitaviiLib08 - Citavireattachment. Contrast-response functions were measured for isochromaticmodulation and for selective modulation of short-wavelength-sensitive (S) andmiddle-wavelength-sensitive (M) cones. At the end of the experiment, retinas wereprepared for light microscopy or immunocytochemical staining with antibodies to rodopsin, S and M cone opsins, cytochrome oxidase, synaptophysin, glial fibrillaryacidic protein (GFAP), cellular retinaldehyde-binding protein (CRALBP),interphotoreceptor-binding protein (IRBP), and peanut agglutinin lectin (PNA).Photoreceptor density maps were created from wholemount preparations labeledwith biotinylated PNA and anti-S cone opsin. Cell counts of photoreceptor nucleiand cone outer segments (OS) were compared with flicker ERG data. Cell deathwas examined by the TUNEL method. RESULTS: Reattachment stoppedphotoreceptor cell death and reversed the disruption of interphotoreceptor matrix aswell as the redistribution of Müller cell proteins. It also activated some astrocytesbased on anti-GFAP staining. S- and M-cone OS showed a gradual recovery inlength after reattachment, and this recovery continued to the longest time pointsexamined. ERG contrast gains also recovered after reattachment, but thesereached asymptotic levels by approximately a week after reattachment. There weresignificant correlations between outer nuclear layer (ONL) cell counts and ERGcontrast gains. No differences were noted in the indices of recovery of M and Scones. CONCLUSIONS: The ERG can be used to follow specifically the changes inthe retina that occur after retinal detachment and reattachment.

Schlagwörter Animals; Cell Death; Contrast Sensitivityphysiology; Electroretinography; EyeProteinsmetabolism; Female; Fluorescent Antibody Technique, Indirect; Male;Microscopy, Confocal; Mitochondriaphysiology; Neurogliaphysiology; PresynapticTerminalsphysiology; Retinal Cone Photoreceptor Cellspathologyphysiology;Retinal Detachmentphysiopathologysurgery; Sciuridae; SulfurHexafluoridetherapeutic use