Spontaneous High Frequency Diameter Oscillations of Larger Retinal Arterioles Are Reduced in Type 2 Diabetes Mellitus

Abstract

Spontaneous high frequency oscillations in the diameter of larger retinal arterioles are reduced in type 2 diabetic patients, and are further reduced during an increase in the arterial blood pressure. The finding may reflect changes in the vascular walls of importance for diagnosing and predicting the visual prognosis in patients with diabetic retinopathy.

The Systemic Blood Pressure and Oxygen Saturation in Retinal Arterioles Predict the Effect of Intravitreal Anti-VEGF Treatment on Diabetic Maculopathy

“…Thus, the measurements of oxygen saturation and diameters in the larger retinal vessels were not performed repeatedly, and, therefore, an influence of dynamic properties of vascular function to the observed effects may have been overlooked. [26][27][28] Additionally, the relationship between increasing CRT and decreasing VA after anti-VEGF treatment can be explained only partially by the findings. Thus, a positive predictive value of VA and CRT before treatment for the same parameters after treatment can be interpreted that the more deranged these parameters were before treatment, the more likely it was that the parameters also were deranged after treatment.…”

The progress in understanding and treatment of diabetic retinopathy

“…It seems likely that diabetes-induced impairment of endothelium-dependent vasorelaxation also contributes to this early vasoconstrictor phase possibly through a mechanism involving downregulation of retinal endothelial TRPV4 channels (De Vriese et al, 2000;Fitzgerald et al, 2005;Ito et al, 2006;Kawagishi et al, 1999;Monaghan et al, 2015;Yu et al, 2003). As diabetic retinopathy develops, the progressive loss of pressure and metabolic autoregulatory mechanisms (Grunwald et al, 1984;Patel et al, 1994;Rassam et al, 1995;Sinclair et al, 1982;Trick et al, 2006) disturbances in retinal vasomotion (Bek, 2013;Bek et al, 2013b) and the release of dilatory factors from the hypoxic retina such as lactate, adenosine and VEGF (Clermont et al, 1997;Gidday and Park, 1993;Hein et al, 2006;Yamanishi et al, 2006) most likely underlies the switch to retinal hyperperfusion (Curtis and Gardiner, 2012). Further research elucidating the basic mechanisms controlling blood flow autoregulation in the retina will be essential if we are fully understand why this process becomes disrupted during diabetes.…”

The Time Course of Changes in Retinal Vessel Diameter in Response to Differing Durations of Flicker Light Provocation

“…This is likely because 20 seconds of provocation begins to saturate the arterial response in both healthy and clinical groups reducing parametric differences between the vessel reactions. The parametric measurements currently available are also extremely limited and alternatives to SDRA, such as area-under-curve analysis 9 and spectral analysis 17,18 are much less established and seem to show similar degrees of overlap between clinical groups. A comprehensive functional or descriptive model of the entire vessel reaction process to FL provocation is lacking but would likely provide better means of assessing the reaction profile in different clinical groups.…”

“…Additionally baseline diameter fluctuation (peakto-trough amplitude prior to flicker onset), dilation amplitude (difference between maximum and minimum dilation), and time to reach maximum dilation can also be assessed and this set of five parameters is sometimes termed sequential diameter response analysis (SDRA) 16 ; though note other forms of analysis have been attempted. 9,17,18 The aim of this study was firstly to evaluate how FL duration affected the various SDRA parameters; for example, how is maximum dilation/ maximum constriction affected by flicker duration? The second goal was to evaluate individual flicker cycles and assess the variability in SDRA parameters across flicker cycles in protocols of different FL duration.…”