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Abstract #20016 Published in IGR 9-4
Decreased nasal-temporal asymmetry of the second-order kernel response of multifocal electroretinograms in eyes with normal-tension glaucoma
Asano E; Mochizuki K; Sawada A; Nagasaka E; Kondo Y; Yamamoto TJapanese Journal of Ophthalmology 2007; 51: 379-389
PURPOSE: To determine whether multifocal electroretinograms (mfERGs) can provide an index for identification of glaucomatous optic neuropathy in patients with normal-tension glaucoma (NTG). METHODS: mfERGs were recorded in 30 normal volunteers (30 eyes) and 20 patients (20 eyes) with normal-tension glaucoma (NTG). Visual field examinations were performed with a Humphrey field analyzer, and all NTG patients had unilateral hemifield defects. The mfERGs were elicited by a binary m-sequence of flashes from 37 hexagonal elements that subtended an overall visual angle of 50° x 40°. The mfERGs were summed and analyzed for predetermined retinal loci. These mfERGs were compared with the perimetric findings of the corresponding visual fields. RESULTS: In normal volunteers, the amplitude of the second-order kernel within the central 5° of the nasal hemisphere was significantly smaller than in that of the temporal hemisphere (Wilcoxon signed-rank test, P = 0.0001). In NTG patients, this asymmetry of the two hemispheres was reduced or not present. The ratio of the amplitude of the mfERGs from the nasal and temporal hemispheres (N/T amplitude ratio) in normal control volunteers was significantly different from that of NTG patients with a hemifield defect (analysis of variance, P = 0.0001). When the cutoff value for the N/T amplitude ratio was set at 0.83 for discriminating glaucomatous eyes from normal eyes, the sensitivity was 65.0% with a specificity of 96.7%. The area under the receiver-operating characteristic curve of the N/T amplitude ratio was 0.86. The N/T amplitude ratio and the visual field indices were significantly correlated. CONCLUSION: A decrease in the nasal-temporal asymmetry in the amplitude of the second-order kernel responses within the central 5° of glaucoma patients' eyes indicated a dysfunction of the inner retinal layers, including of the retinal ganglion cells.
Dr. E. Asano, Department of Ophthalmology, Gifu University Graduate School of Medicine, Gifu, Japan
Classification:
9.2.4 Normal pressure glaucoma (Part of: 9 Clinical forms of glaucomas > 9.2 Primary open angle glaucomas)
6.7 Electro-ophthalmodiagnosis (Part of: 6 Clinical examination methods)
