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Mali Okada, Anthony G Robson, Catherine A Egan, Ferenc Sallo, Simona Degli Esposti, Tjebo FC Heeren, Graham E Holder; Electrophysiological Characterization of Macular Telangiectasia Type 2 (MacTel). Invest. Ophthalmol. Vis. Sci. 2017;58(8):4886.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the electrophysiological features of Macular Telangiectasia type 2 (MacTel) and their relationship to structure as determined by optical coherence tomography (OCT) imaging.
Retrospective observational study of patients enrolled in the MacTel Natural History Observation Study who had electrophysiological study as part of their diagnostic work-up. Forty-two eyes from 21 patients were analysed. All patients had full-field (ERG) and pattern (PERG) electroretinography with a subset of patients (n=13) additionally having multifocal electroretinography (mfERG). Multiple linear regression modelling assessed the relationship between size of the ellipsoid zone break on en-face OCT imaging to the mfERG central hexagon response amplitude.
Full-field ERG was normal in all 42 eyes. Eleven eyes (26%) had subnormal PERG P50 amplitudes. Twenty of 26 eyes (77%) had reduced central or paracentral stimulus response on mfERG. There was a significant correlation between ellipsoid zone break size and both the P1 amplitude (Correlation coefficient B = -1.4, p = 0.002, overall model R2 = 0.46) and P1:N1 ratio (B = -0.7, p = 0.002, R2 = 0.45) of the central hexagon on mfERG.
The electrophysiological findings are consistent with the central localized involvement of MacTel type 2 demonstrated by OCT imaging and known from histological examination. There is a relationship between ellipsoid zone break size and mfERG reduction. The reduced P1:N1 ratio is in keeping with an inner retinal site of dysfunction. The mfERG is more sensitive than the PERG in demonstrating the highly localised dysfunction present in MacTel.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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