The time course of changes in retinal vessel diameter in response to differing durations of flicker light provocation

Purpose: To determine the response of retinal vessels to differing durations of flicker light (FL) sitmulation. Methods: We recorded retinal arterial and venous vessel dilation to 12.5 Hz flicker light provocation (Retinal Vessel Analyzer, Imedos Systems) of varying duration (5, 7, 10 and 20 seconds) in twelve healthy young individuals (age range 26-45 yrs). All participants underwent a full ocular examination including intraocular pressure and blood pressure measurements. Results: Maximum dilation (MD) did not show a significant dependence on flicker duration in arteries whereas maximum constriction (MC) did. However, in veins MD significantly increased with flicker duration. Approximately 80-90% of MD in arteries is reached within 10 seconds of flicker light stimulation. Conclusions: The vast majority of arterial dilatory capacity is reached within 10 seconds of flicker light stimulation even though venous dilation continues strongly. Since the MC of arteries shows a significant dependence on flicker duration measurements at two different durations can provide more information about the retinal vascular system than at a single flicker duration alone.

What next for unions in Central and Eastern Europe? Invisibility, departure and the transformation of industrial relations

This article examines union revitalization in Central and Eastern Europe, focusing on two countries: Hungary and Latvia. Trade unions have not only had to cope with a declining membership base, but have also had to respond to austerity programmes and government cuts in public sector employment. We argue that the inability of unions to provide a strong voice for alternative policies to the current neoliberal orthodoxy has been driven by a declining membership base, but also by weakened social dialogue mechanisms, limited industrial representation and an ageing membership profile, exacerbated by net outward migration in recent years. However, we find that unions in Latvia and Hungary have responded differently to these issues.