April 2011
Volume 52, Issue 14
Free
ARVO Annual Meeting Abstract  |   April 2011
Photopic On- And Off- Erg Responses To Square Wave And Sawtooth Modulations In Humans
Author Affiliations & Notes
  • Gobinda Pangeni
    Ophthalmology, University Hospital Erlangen, Erlangen, Germany
  • Jan Kremers
    Ophthalmology, University Hospital Erlangen, Erlangen, Germany
  • Footnotes
    Commercial Relationships  Gobinda Pangeni, None; Jan Kremers, None
  • Footnotes
    Support  DFG KR1317/9-1
Investigative Ophthalmology & Visual Science April 2011, Vol.52, 689. doi:
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      Gobinda Pangeni, Jan Kremers; Photopic On- And Off- Erg Responses To Square Wave And Sawtooth Modulations In Humans. Invest. Ophthalmol. Vis. Sci. 2011;52(14):689.

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Abstract

Purpose: : To describe the on- and off-response components elicited by square wave and sawtooth stimuli at different temporal frequencies and contrasts. Furthermore, asymmetries between the on- and off-responses, originating in nonlinear response mechanisms (similar to those involved in the pattern ERG), were studied.

Methods: : Full-field stimuli were produced using a ganzfeld bowl with white LEDs as light sources. ERG responses were recorded using DTL electrodes from 6 normal subjects using square wave and sawtooth stimuli (mean luminance 250 cd/m²) at different temporal frequencies and contrasts. In addition, the on- and off-responses were added to study the asymmetries between the two. The amplitudes and implicit times of components in on- and off-response and in additions (a-wave, b-wave, d-wave, PhNRon, PhNRoff, a-add, b-add and PhNRadd) were measured. Effects of contrast and temporal frequency were statistically analyzed.

Results: : The amplitudes of the all components elicited by square wave stimuli did not depend strongly on temporal frequency except the PhNRs. All response components elicited by sawtooth stimuli decreased significantly in amplitude with increasing temporal frequency. All the component amplitudes were positively correlated with stimulus contrast. The implicit times of a- and b-waves elicited by square wave stimuli decreased significantly with increasing temporal frequency. In contrast, those of a-, b- and d-waves in responses to sawtooth stimuli decreased significantly with increasing temporal frequency.The implicit times of all PhNRs components decreased continuously with increasing temporal frequency. Only the implicit time of b-wave components decreased significantly with decreasing contrast. The responses of additions were similar to those of the PERG. The b-add and PhNRadd components had similar properties as the P50 and N95 components of the PERG.

Conclusions: : Temporal frequency and contrast of luminance square wave and sawtooth stimuli had different effects of on- and off-response responses. The asymmetries between on- and off-responses displayed similar properties as the PERG.

Keywords: electroretinography: non-clinical • retina: distal (photoreceptors, horizontal cells, bipolar cells) • retina: proximal (bipolar, amacrine, and ganglion cells) 
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