September 2016
Volume 57, Issue 12
Open Access
ARVO Annual Meeting Abstract  |   September 2016
Flicker Response of Venous Oxygen Saturation Significantly Reduced in Both Early and Late Stages of Age-Related Macular Degeneration
Author Affiliations & Notes
  • Emilia Donicova
    Experimental Ophthalmology, Jena University Hospital , Jena, Germany
  • Lisa Ramm
    Experimental Ophthalmology, Jena University Hospital , Jena, Germany
  • Martin Hammer
    Experimental Ophthalmology, Jena University Hospital , Jena, Germany
  • Regine Augsten
    Experimental Ophthalmology, Jena University Hospital , Jena, Germany
  • Footnotes
    Commercial Relationships   Emilia Donicova, None; Lisa Ramm, None; Martin Hammer, None; Regine Augsten, None
  • Footnotes
    Support  None
Investigative Ophthalmology & Visual Science September 2016, Vol.57, 2657. doi:
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      Emilia Donicova, Lisa Ramm, Martin Hammer, Regine Augsten; Flicker Response of Venous Oxygen Saturation Significantly Reduced in Both Early and Late Stages of Age-Related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2657.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Age-related macular degeneration ist the leading cause of vision loss in people aged 65 and over. Although this desease has been researched for years, only a few risk factors were identified and the exact etiology remains unclear. Therefore, our purpose was to investigate whether retinal oxygen saturation as well as its alternation under flicker light stimulation plays a role in development and progression of ARMD. Furthermore, potential differences between specific ARMD subgroups, including early and late stages, were explored.

Methods : 60 eyes of 45 AMD patients (mean age 75 years±8.3) and 23 controls (73 years±7.4) were included. Retinal vessel oxygen saturation (SO2) of all arterioles and venules in a 30-degree field, centered at the optic disc, was measured before and during the stimulation of neuronal activity by flicker light. The Retinal Vessel Analyser's oximetry module (Imedos UG), based on dual-wavelength oximetry principles, was used. The flicker light (12.5 Hz) was applied for a period of 90 seconds. A subgroup analysis was performed on patients with early AMD, neovascular AMD, geographic atrophy and disciform scar. Mean SO2 values were compared by t-test and Mixed Linear Model respectively. The flicker response of the arteriovenous oxygen saturation difference was calculated according to Fig. 1. A p-value < 0.05 was considered as significant.

Results : Neither arterial (98.4±4.3 vs. 97.7±5.2) nor venous SO2 (63.4±8.2 vs. 61.1±9.4) nor the arteriovenous SO2 difference (AVD, 35.0±6.2 vs. 36.6±7.4) were significantly different between patients and controls. However, compared to the physiological results (-4.87±3.48), the flicker response of the arteriovenous oxygen saturation difference was significantly reduced in early AMD (-2.42±3.04, p=0.019), geographic atrophy (-0.32±4.68, p=0.019) and disciform scar (-1.91±2.21, p=0.033). A nearly significant reduction occurred in neovascular AMD (-2.93±3.77, p=0.066) as well (Fig. 2). Among the subgroups themselves only minimal differences with no statistical significance were found.

Conclusions : The greatest reduction of flicker response occurs in late AMD stages (geographic atrophy, disciform scar). These significant changes are seen in early AMD as well. The results indicate that the neurovascular coupling is seriously affected in AMD or that the oxygen consumption by the inner retina may be decreased.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

 

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