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H. Chakor, C. Lavigne, J. Little, R. Koenekoop, R. Polomeno, M. Hébert, P. Lachapelle; Evidence Suggesting a Center to Periphery Organisation of Multifocal ERG Oscillatory Potentials (mfOPs) . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3428.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Compare the ring organisation of multifocal oscillatory potentials (mfOPs) evoked from normal subjects and patients affected with OPs selective retinopathies (i.e. selectively abolishing OP2, OP3 or OP4 as per full field flash evoked OPs: fOPs). Methods: Photopic (flash: 0.9 log cd.m–2.sec; background: 30 cd.m–2) fOPs and mfOPs (37 hexagons, mean luminance 400 cd.m–2 ) were recorded from normal subjects (N=15) and patients affected with OP selective retinopathies (N=15) . The m–sequence was gradually slowed down by adding 2,4,6 and 10 dark frames between consecutive stimulus frames. Only the first order kernel was analysed. Results: Slow m–sequence mfOPs (10 dark frames) responses included three major OPs (OP2, OP3, OP4) of relative amplitude identical (p>.05) to the fOPs, albeit mfOPs being, on average, 1 msec. faster than fOPs. Progressively faster m–sequences gradually eliminated the short latency OP2, OP3, leaving only OP4 (2 dark frames), in a fashion identical to what we observed in slow flicker (<20Hz) evoked fOPs . For central rings, removal of the earlier OPs was obtained at significantly (p<.05) slower m–sequences compared to peripheral ones. The concentric organisation of individual mfOPs was further confirmed in ring analysis of responses gathered during the photopic light adaptation effect [100% increase of fOPs and mfOPs OP4 (p<.05) while other OPs are not affected (p>.05)] as well as in ring analysis of mfOPs recordings obtained from patients with documented (as per fOPs) abolition of OP2 and OP3 (such as CSNB) or OP4 (such as cone dystrophy) where remnants of the absent OPs (as per fOPs) could still be evidenced in alleged source rings. Conclusions: Our results thus strongly support : 1–that fOPs and mfOPs are generated through the same retinal pathways and 2– either a possible central to peripheral shift in the orientation of the individual OPs dipoles or central (OP2, OP3) to peripheral (OP4) origin of individual OPs.
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