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K. Tamada, S. Machida, D. Yokoyama, D. Kurosaka; The Photopic Negative Response of Full-Field and Focal Electroretinograms in Patients With Optic Nerve Atrophy. Invest. Ophthalmol. Vis. Sci. 2009;50(13):5314.
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To determine how the photopic negative response (PhNR) of the full-field and focal electoretinograms (ERG) is altered in patients with optic nerve atrophy.
Eight eyes of 6 patients with optic nerve atrophy induced by compression, inflammation or undetermined etiology were examined. There were 4 women and 2 men with a mean age of 51 years. Thirty age-matched controls were examined with the same protocol. The full-field cone ERGs were elicited by red stimuli on a blue background. The focal ERGs were elicited by a 15° white stimulus spot centered on the macular region. Amplitudes of the a- and b-waves as well as the PhNR of the full-field and focal ERGs were compared between controls and affected eyes.
There was no significant difference between the controls and affected eyes with optic nerve atrophy in the a- and b-wave amplitudes of the full-field and focal ERGs. The PhNR amplitudes of the full-field ERG were abnormally reduced in 5 out 8 affected eyes. The three eyes with normal amplitudes of the full-field PhNR had central scotomas with atrophy localized in the temporal sector of the optic nerve head. The amplitudes of the focal PhNR were below of the normal range in all affected eyes with significant difference from normal controls (P<0.001).
Both full-field and focal PhNRs were attenuated in eyes with optic nerve atrophy, indicating that focal PhNR also originates from RGCs and their axons. The focal PhNR would be better to detect local damage to RGCs and their axons than the full-field PhNR.
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