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BA E Mazinani, A Amjadi, AW A Weinberger, NF Schrage; Experiences with LED Stimulation in Multifocal Electroretinography . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1795.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To report about first experiences with the new stimulation technique of LED-stimulation in multifocal electroretinography, that permits a more precise stimulation by presenting simultaneous image to the different retinal areas in contrast to CRT-monitor stimulation, where the raster image is built up line by line. Methods: We examined 6 healthy volunteers and two patients with retinitis pigmentosa both with CRT monitor stimulation using binary M-sequences and with stimulation by a LED-display. (RETIscan by Roland Consult, Wiesbaden). The LED system permits to carry out the stimulation either by conventional M-sequences or by cyclic summation. In cyclic summation, each array of the stimulation pattern is triggered with a slightly different amplitude of about 30 Hz. After the recording, the amplitudes of the single areas can be traced back according to the principles of a Fourier analysis. An examination of an area of 30° with a resolution of 61 hexagons takes about 4 min using M-sequences. Because of a better sinal-to-noise-ratio the same examination takes about 32 sec. Results: The comparison of the two stimulation methods showed that the amplitudes generated by cyclic summation result in a retinal topography with a central peak and a peripheral decrease which reflects the retinal photoreceptor density as do the amplitudes generated by M-sequences. Pathological amplitude patterns in the cases of retinitis pigmentosa could be reproduced by cyclic summation. No significant difference in amplitude size could be detected. Conclusion: Our examinations showed, that stimulation by LED-diplays and cyclic summation give comparable results while requiring shorter examination times. Future studies with larger numbers of subjects will have to prove if repeatability and inter- and intraindividual stability are also of equal quality.
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