The first and second harmonics of the macular flicker electroretinogram: Differential effects of retinal diseases

Benedetto Falsini, Vittorio Porciatti, Antonello Fadda, Erasmo Merendino, Giancarlo Iarossi, Silvano Cermola

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

We evaluated the effects of retinal diseases on the macular electroretinogram first and second harmonic components, which are dominated by outer and inner retinal activity, respectively. Macular electroretinograms in response to a uniform field (9° × 9°) flickering sinusoidally at either 32 or 8 Hz (peak frequencies of the first and second harmonics, respectively) were recorded in 14 patients with maculopathies involving photoreceptors (e.g., age-related macular degeneration), in 16 patients with postreceptoral macular diseases (e.g., branch occlusion of central retinal artery), and in 38 normal controls. Amplitude and phase of the first and second harmonic response components were evaluated by Fourier analysis. When compared to controls, patients with photoreceptor diseases had reduction in both first and second harmonic mean amplitudes and second harmonic phase delay; patients with postreceptoral diseases had normal first harmonic components but reduced and delayed second harmonic components. A discriminant analysis, by using first and second harmonic values, correctly classified 13 of 14 patients with photoreceptor diseases and 14 of 16 patients with postreceptoral disorders. These results indicate that combined evaluation of the macular electroretinogram first and second harmonic components is a useful test for identifying the site(s) of retinal dysfunction in patients with macular diseases.

Original languageEnglish (US)
Pages (from-to)157-167
Number of pages11
JournalDocumenta Ophthalmologica
Volume90
Issue number2
DOIs
StatePublished - Feb 1 1995
Externally publishedYes

Keywords

  • First harmonic
  • Flicker stimulus
  • Inner retina
  • Macular electroretinogram
  • Photoreceptors
  • Second harmonic

ASJC Scopus subject areas

  • Ophthalmology

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