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K. E. Kotliar, S. Al-Barazanji, A. Kharoubi, C. von Düring, I. Lanzl; Does the Microstructure of Retinal Venous Blood Column Change in Primary Open Angle Glaucoma?. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2707.
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© ARVO (1962-2015); The Authors (2016-present)
We demonstrated previously that roughness of the retinal artery blood column measured along the vessel axis and termed longitudinal vessel profile (LVP) increases significantly in arteries of glaucoma patients during prnounced vasodilation. Whether LVP is altered in retinal veins of glaucoma patients is investigated.
Retinal venous reactions to flicker stimulation were examined by Dynamic Vessel Analyzer (DVA, IMEDOS, Jena, Germany) in 28 patients with primary open-angle glaucoma (POAG, stage I, 60.9±12.6 years old, IOP: 20.5±4.3 mmHg) after 4 week wash-out of eye drops and in 28 age and gender matched medically healthy volunteers (58.8±10.5 years old, IOP: 15.6±2.1 mmHg). After baseline assessment for 1 min a monochromatic (530-600nm) rectangular luminance flicker of 12.5 Hz was applied for 20 s. In venous segments of approximately 1 mm in length vessel diameters were measured in order to obtain LVP at different stages of venous reaction to flicker. Differences in amplitude and frequency of spatial vessel diameter changes were analysed using Fourier transformation.
Power spectra of longitudinal venous profiles both in healthy subjects and in POAG patients do not change significantly during all stages of the venous response to flicker. Compared to the veins of healthy subjects, LVP in POAG patients showed pronounced waves with a period of 62.5 - 83.3 µm at all stages of the venous reaction. This was significant at baseline and dilation (p<0.05, T-Test). Basic period of LVP corresponds to the maximal frequency of power spectrum. This amounted to 607- 622 µm in healthy LVPs and to 380 - 407 µm in LVPs of POAG patients at different stages of venous reaction (p<0.05).
Retinal vessels possess alternating vessel diameters which constitute the vessel longitudinal section profile. Increased IOP in the POAG group which compresses retinal veins could be causative for those microstructural changes. We assume however that the observed changes in the retinal venous blood column in patients with primary open angle glaucoma are an indication for alterations in the vascular endothelium in glaucoma, leading to impaired venous perfusion and vascular regulation in this disease.
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