Abstract
Purpose :
Diabetic eye disease manifests through vascular changes visible in retinal photographs and used for classification purposes. Such changes, as characterized by microanyrisms, haemhorrages, exudates, intraretinal vascular abnormalities, neovascularisations, cotton wool spots and edema, are all a consequence of vascular dysfunction. We demonstrated previously that non-stimulated temporal retinal vessel oscillations (pulsations and vasomotions) are changed in patients with diabetes mellitus type 1 with no or non-proliferative retinopathy. The aim of the present study was to explore these dynamic microvascular alterations in the eye in patients with diabetes mellitus type 2 (T2DM) free from diabetic eye disease.
Methods :
13 untreated patients with T2DM (age 64.8 (55.3 – 73.1) years [median (1.quartile – 3. quartile], 9 male, 4 female) with no diabetic retinopathy and 13 age and sex matched medically healthy volunteers were examined by Dynamic Vessel Analyzer (DVA, IMEDOS, Jena, Germany). Temporal changes of vessel diameters of retinal arterial and venous vessel segments were measured with DVA in all subjects during periods of 40 s before and after the application of monochromatic flickering light (530 nm, 12.5 Hz, 20 s) according to the standard protocol. The data was evaluated using methods of signal analysis.
Results :
Arterial and venous pulse amplitude at the baseline was reduced in T2DM in comparison to healthy controls: arteries: 2.5 (2.3 – 2.7) measuring units (MU) vs. 4.4 (4.0 – 4.6) MU, p<0.05; veins: 4.5 (3.6 – 4.6) MU vs. 6.4 (5.0 – 6.9) MU, p<0.05. Additionally, the coefficient of periodicity of venous pulsations in T2DM reduced gradually over three cycles of flicker simulation: from 0.54 (0.25 – 0.69) at the baseline to 0.08 (0.07 – 0.24) after the third flicker (p<0.05). Meanwhile the value of this parameter in healthy volunteers remained almost stable with a tendency to increase: from 0.25 (0.22 – 0.27) at the baseline to 0.32 (0.19 – 0.40) after the third flicker.
Conclusions :
Functional and morphological alterations in the retinal vessel oscillations in T2DM with no sign of retinopathy are shown using a non-invasive in-vivo methodology. These differences in microcirculatory dynamics in T2DM without manifest diabetic retinopathy is likely reflecting early vascular insufficiency and may be a marker of microvascular abnormalities prior to visible changes of vascular damage.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.