Klinische Interpretation retinaler Durchblutungsmessungen

Abstract

Based on the pathomechanism of diabetic retinopathy, the effect of photocoagulation on retinal microcirculation as assessed by measurements of retinal microcirculation magnitudes is discussed. The clinico-experimental results support the opinion that an essential effect of photocoagulation is due to an improvement in the flow conditions of the noncoagulated central retinal area with regard to metabolic exchange and stasis situation by the coagulation-induced occlusion of peripheral capillary areas. Further clinico-experimental measurements of retinal microcirculation magnitudes for the assessment of the behavior of microcirculation after photocoagulation in venous occlusive diseases of the retina are presented. It is shown that retinal microcirculation immediately after photocoagulation reacts by transitory instationary flow conditions; in this period it is quite possible that an additional blood flow reduction over several days will occur. In particular, the effect of photocoagulation in venous occlusive diseases with narrow arterial vessels is discussed. It is emphasized that with regard to the therapeutic effect of photocoagulation as well as to the discussion of pathomechanisms, apart from blood flow, the differentiated behavior of single retinal vascular areas, such as arteries, arterioles, capillaries, venules and veins, requires more attention. Particularly with this in mind, substantial improvements in differential diagnosis and treatment of retinal circulatory disturbances may be expected from measurements of retinal circulation magnitudes.

Retinal Blood Flow Evaluation

“…The importance of measuring retinal BF in retinal venous occlusions as an indicator of the severity of microcirculatory disorders has been discussed. In particular, blood velocity appears to provide an important criterion for the assessment of the stasis conditions and the diameter of the vessels offers essential information on local regulative processes [87,88,89]. Decreased [90] or retrograde [91] BF into the arterioles, as well as blood flowing from the venules into the capillaries [92], were observed in monkey and cat models of BRVO, respectively.…”