Pupil size and the steady-state pattern reversal visual evoked cortical potential

Müller, Winfried; Kollert, Andrea; Zachert, Carolin

doi:10.1007/bf00156441

Cited by 5 publications

(10 citation statements)

References 2 publications

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“…Past studies have investigated the influence of pupil size on the VEP to improve a diagnostic automated pupillometry device, and demonstrated that both extremely constricted and dilated pupils deteriorated the signal-to-noise ratio of pupillometry as compared to a normal pupil (Hawkes and Stow, 1981;Lovasik et al, 1985;Muller et al, 1988;Martins et al, 2003;Salim et al, 2010;Sabeti et al, 2011). The underlying mechanisms should include not only pupillary light reflex, but also non-visual factors such as arousal, attention, and cortical state, yet it is difficult to quantify each contribution in VEP.…”

Section: Evoked Response Vs Pupil Sizementioning

confidence: 96%

Covariation of pupillary and auditory cortical activity in rats under isoflurane anesthesia

et al. 2015

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Section: Evoked Response Vs Pupil Sizementioning

confidence: 96%

Covariation of pupillary and auditory cortical activity in rats under isoflurane anesthesia

et al. 2015

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“…Pupil size has been recognized as an important variable when recording a visual evoked potential (VEP), as it determines the quantity of light entering the eye 1−4 . Full field pattern‐VEP studies showed a decrease in latency with increasing pupil diameter 1,2 .…”

Section: Introductionmentioning

confidence: 99%

“…found a small reduction in amplitude as the pupil dilated. The effect of spatial frequency on the relationship between pupil size and amplitude has been examined 3 . Pupil size was found to influence pattern VEP amplitude only at the highest tested frequency, where an inverse relationship was noted.…”

Section: Introductionmentioning

confidence: 99%

Effect of pupil size on multifocal pattern visual evoked potentials

Martins

Bala

Klistorner

et al. 2003

Clinical Exper Ophthalmology

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The purpose of this study was to investigate the influence of pupil diameter on the amplitude and latency of multifocal visual evoked potentials (mfVEP). The multifocal objective perimeter (Accumap; Objectivision) was used to stimulate the visual field at 56 sites extending to 32 degrees using a pseudo-random pattern stimulus. The mfVEP were recorded using bipolar occipital electrodes, 7 min/eye. Ten normal subjects were recruited from the community and one eye was randomly selected for testing. The mfVEP were recorded at four different pupil diameters (2 mm, 4 mm, 6 mm, 8 mm), obtained by applying tropicamide (0.5%) or pilocarpine (2%) in different dilutions. Appropriate refractive correction was provided to overcome cycloplegia and achieve a visual acuity of 6/7.5 or better. Analysis revealed that at most pupil diameters the normalized full field amplitude did not show significant variation, except at the most miotic pupil diameter (2 mm), where the amplitude became reduced, based on 2-way anova and Tukey's T method. There was, however, significant correlation between latency and pupil area (correlation coefficient: upper field -0.63, lower field -0.76). The results suggest that even in the presence of mydriatics or miotics, the mfVEP test can be used to assess diseases that affect amplitude, provided near correction is used. The interpretation of latency, however, must be made with caution, as a borderline conduction defect with a dilated pupil may appear normal.

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“…Advantages of icVEP compared with mfVEP include shorter test duration and more meticulous and detailed quantification of the SNR response through the use of multivariate statistical analysis. Muller et al [26] also reported a statistically significant influence of pupil size on steady-state pattern reversal visual evoked cortical potentials.…”

Section: Discussionmentioning

confidence: 94%

Influence of pupil size and other test variables on visual function assessment using visual evoked potentials in normal subjects

et al. 2010

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The purpose of this study was to assess the influence of pupil size and optical blur on measurements obtained with isolated-check visual evoked potential (icVEP). Two stimulus conditions of icVEP, +15 and -15% contrasts, were studied in normal subjects with normal (N), miotic (M), and dilated (D) pupils. The effects of optical blur were studied in subjects with normal pupil. Response to visual stimuli was quantified by a signal-to-noise (SNR) ratio. In 30 normal subjects, the mean age was 26.0 +/- 3.4 years. Mean pupil diameters were N = 4.2 +/- 0.6 mm, M = 2.7 +/- 0.6 mm, and D = 7.3 +/- 0.9 mm. For both +15 and -15% contrast levels, mean SNR values were reduced for dilated and constricted pupils when compared with normal pupils. Mean SNR values for optical blur with a +2 or +3 diopter lens placed over the distance correction were reduced when compared with SNR measurements obtained with best-corrected visual acuity under both +15 and -15% contrast levels. Statistical significance was found in comparisons of N versus M (P < 0.001) and N versus D (P = 0.002) for +15 and -15% contrast conditions, respectively. No statistical difference was seen for M versus D (P = -0.435). The effect of optical blur was statistically significant when compared to the normal pupils with best-corrected vision (P < 0.001). No statistically significant difference was found comparing +2 and +3 diopters lenses for optical blur testing. Visual evoked potential values are influenced by pupillary constriction and dilation, as well as optical blur. When obtaining icVEP measurements, the influence of pupil size and optical blur should be kept in mind for accurate interpretations.

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Pupil size and the steady-state pattern reversal visual evoked cortical potential

Cited by 5 publications

References 2 publications

Covariation of pupillary and auditory cortical activity in rats under isoflurane anesthesia

Covariation of pupillary and auditory cortical activity in rats under isoflurane anesthesia

Effect of pupil size on multifocal pattern visual evoked potentials

Influence of pupil size and other test variables on visual function assessment using visual evoked potentials in normal subjects

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