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Takaaki Kondo, CS Matsumoto, Shingo Satofuka, Kei Shinoda, Harue Matsumoto, Hideaki Funada, Mitsuya Ikejiri, Atsushi Mizota; Liquid Crystal Display Monitors As A Visual Stimulator For Recording Pattern-reversal Visual Evoked Potentials: Usefulness And Limitations. Invest. Ophthalmol. Vis. Sci. 2011;52(14):6090. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Liquid crystal display (LCD) have been thought to be a substitute for cathode-ray tube (CRT) monitors as visual stimulator to record pattern-reversal visual evoked potential (p-VEP). The purpose of this study is to evaluate the usefulness of LCD monitors as a visual stimulator to record p-VEPs.
Chekerboard pattern-reversal stimulus was used to elicit p-VEPs according to the ISCEV protocol. Checkerboard pattern was 1 and 0.25 degree in size, at a frequency of 3 rev/sec. The waveforms of p-VEPs stimulated by LCD monitor were compared with those by the conventional CRT monitors. Reduce of the flashing effect was obtained by changing the contrast of the LCD monitor (81 to 97%).
The stimulation by use of LCD showed the same waveform containing the components (N75, P100) of the conventional p-VEP. However, the amplitude of the P100 increased and the implicit time was delayed in the p-VEP recorded using LCD compared to the conventional p-VEP recorded using CRT monitor. It is partly because flashing due to LCD’s inherent time delay during the checkerboard reversal, especially from black to white. The temporal reduction of the mean luminance was reduced by 49% when the contrast was changed from 97% to 81%. And the differences of the amplitude and the implicit time of P100 were smaller in the p-VEP with a contrast of 81% compared to those with 97%.
The p-VEP waveforms are influenced by delay in reversal phase when using LCD. But the flashing effect might be reduced by optimizing the contrast of the checkerboard luminance.
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