Posters

Factors determining flicker-induced retinal vasodilatation in healthy subjects

Poster Details

First Author: M. Sharifizad AUSTRIA

Co Author(s):    L. Schmetterer   K. Witkowska   G. Garhofer   G. Aschinger   S. Sapeta   D. Schmidl     

Abstract Details

Purpose:

To analyze factors determining the retinal arterial and venous response to stimulation with diffuse luminance flicker in healthy subjects.

Setting:

In the recent years evidence has accumulated that flicker-induced retinal vasodilation is altered in a variety of ocular and systemic diseases. In the present study we set out to analyze determinants of flicker-induced vasodilatation in healthy subjects.

Methods:

We retrospectively analyzed results obtained in 374 healthy subjects that participated in clinical studies. Of those 153 subjects underwent a protocol in which flicker stimulation was delivered through the fundus camera at 8 Hz, separating measurement and stimulation light dependent on the wavelength and 221 subjects underwent a protocol in which diffuse luminance flicker was delivered at 12.5 Hz with high modulation depth . We investigated whether gender, systemic blood pressure, baseline vessel size, blood plasma concentration of fasting glucose and hematocrit, serum concentration of cholesterol, triglycerides, creatinine and C-reactive protein influence the retinal vascular response to flicker stimulation.

Results:

Flicker responses in arteries and veins were more pronounced in protocol 2 as compared to protocol 1 (p < 0.001 each). In both protocols the vascular response to stimulation with diffuse luminance flicker was larger in smaller vessels (p values between 0.001 and 0.016). In protocol 2 the retinal arterial flicker response was negatively associated with cholesterol serum levels (p = 0.033), in protocol 1 only a tendency towards this effect was observed (p = 0.056).

Conclusions:

The present analysis indicates that retinal arterial and venous responses to stimulation with diffuse luminance flicker depend on the way the stimulation is delivered through the fundus camera. In addition, the flicker response varied with the vessel size, the smaller the vessel width, the larger the flicker response. Finally our data indicate that even within the normal range higher cholesterol serum levels are associated with lower hyperemic flicker responses.

Financial Disclosure:

NONE