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R. Blanco, J.A. Alvarado, E.E. Sutter; Multifocal Electroretinogram Responses in Glaucoma Patients With Unilateral Hemifield Defects . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3752.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: 1. To evaluate the electrophysiologic function in glaucoma patients and unilateral visual field defects in the achromatic automated perimetry (AAP) by using a new protocol of the multifocal electroretinogram (mf–ERG) that emphasizes response contributions from ganglion cell fibers (optic nerve head component (ONHC)). Methods: mfERGs in both eyes of 14 individuals with open–angle glaucoma and unilateral hemifield defects were recorded and analysed with the VERIS 5.1 multifocal recording system. The special, ganglion cell response enhancing protocol consisted of multifocal flash stimuli interleaved with two global flashes presented 13.3 ms and 40 ms after each multifocal frame. The intensity of both multifocal and global flashes was 2.7 cd•s/m^2. The stimulus array consisted of 103 scaled hexagons. The recording time was 9 minutes per each eye. Pupils were dilated. The effect induced by the focal flashes on the second one of the following global flashes contains the most prominent ONHC and was thus used for the evaluation of the mfERG data. ERG responses for each individual sector were compared with an age–matched normals database, and probability of abnormality plots were made. Results:Significant mfERG deficits were detected in the affected AAP hemifield in 13 of 14 (92.8%) glaucoma patients and in 11 of 14 (78.5%) patients in hemifields with apparently normal AAP. Of the 56 hemifields tested (14 patients x two eyes x two hemifields), 14 showed significant defects on the HVF and 28 showed significant deficits on the mfERG. Overall, the HVF and the mfERG results agreed on 40/56 (71.4%) of the hemifields, and 13 hemifields were abnormal and 27 hemifields were normal on both the mfERG and HVF tests. Of the 16 hemifield disagreements, 15 (26.7 %) hemifields had significant deficits on the mfERG but not on the AAP, whereas the reverse was seen just in 1 (1.7%) hemifields.Conclusions: 1) This study provides evidence that the mfERG technique can detect and map early functional deficits in glaucoma that are not apparent using current automated perimetry tests. 2) The mfERG has the potential to be a useful tool in the early detection of functional deficits in glaucoma and its longitudinal assessment as new stimulation and analysis protocols are being improved.
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