Messung von strömungsphysiologischen Größen der Netzhautdurchblutung bei Normalpersonen

Oswald, B; Vilser, Walthard; Oswald, Hanno; Jütte, A; Königsdörffer, E.; Schweitzer, Dietrich

doi:10.1007/bf02307014

Cited by 10 publications

(4 citation statements)

References 4 publications

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“…Combining measurements of blood flow (Cunha-Vaz and Lima, 1978;Oswald et al, 1983;Riva et al, 1972;Sato et al, 2006;Vilser et al, 1986) and of arterial oxygen saturation (Beach et al, 1999;Delori et al, 1981;Hickham et al, 1963;Laing et al, 1975;Schweitzer et al, 1999Schweitzer et al, , 1995 the supply of the tissue with oxygen can be calculated. Additionally, the arterio-venous difference of the oxygen saturation enables an estimation of the oxygen consumption in the tissue.…”

Section: Introductionmentioning

confidence: 99%

Towards metabolic mapping of the human retina

Schweitzer

Schenke

Hammer

et al. 2007

Microscopy Res & Technique

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Functional alterations are first signs of a starting pathological process. A device that measures parameter for the characterization of the metabolism at the human eye-ground would be a helpful tool for early diagnostics in stages when alterations are yet reversible. Measurements of blood flow and of oxygen saturation are necessary but not sufficient. The new technique of auto-fluorescence lifetime measurement (FLIM) opens in combination with selected excitation and emission ranges the possibility for metabolic mapping. FLIM not only adds an additional discrimination parameter to distinguish different fluorophores but also resolves different quenching states of the same fluorophore. Because of its high sensitivity and high temporal resolution, its capability to resolve multi-exponential decay functions, and its easy combination with laser scanner ophthalmoscopy, multi-dimensional time-correlated single photon counting was used for fundus imaging. An optimized set up for in vivo lifetime measurements at the human eye-ground will be explained. In this, the fundus fluorescence is excited at 446 or 468 nm and the time-resolved autofluorescence is detected in two spectral ranges between 510 and 560 nm as well as between 560 and 700 nm simultaneously. Exciting the fundus at 446 nm, several fluorescence maxima of lifetime t1 were detected between 100 and 220 ps in lifetime histograms of 40 degrees fundus images. In contrast, excitation at 468 nm results in a single maximum of lifetime t1 = 190 +/- 16 ps. Several fundus layers contribute to the fluorescence intensity in the short-wave emission range 510-560 nm. In contrast, the fluorescence intensity in the long-wave emission range between 560 and 700 nm is dominated by the fluorescence of lipofuscin in the retinal pigment epithelium. Comparing the lateral distribution of parameters of a tri-exponential model function in lifetime images of the fundus with the layered anatomical fundus structure, the shortest component (t1 = 190 ps) originates from the retinal pigment epithelium and the second lifetime (t2 = 1,000 ps) from the neural retina. The lifetime t3 approximately 5.5 ns might be influenced by the long decay of the fluorescence in the crystalline lens. In vitro analysis of the spectral properties of expected fluorophores under the condition of the living eye lightens the interpretation of in vivo measurements. Taking into account the transmission of the ocular media, the excitation of NADH is unlikely at the fundus.

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Section: Introductionmentioning

confidence: 99%

Towards metabolic mapping of the human retina

Schweitzer

Schenke

Hammer

et al. 2007

Microscopy Res & Technique

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203

240

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“…Die Abbildung 2 stellt die Abhängigkeit der arteriellen Blutgeschwindigkeit vom Al ter nach den Messwerten von Oswald et al [1983] Oswald et al [1983] vorgestelltc Altersabhängigkeit, der arteriellen Blutge schwindigkeit. Ein Vergleich dieser Altersab hängigkeit mit der des retinalen Blutflusses [Vilser et al.…”

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Klinische Interpretation retinaler Durchblutungsmessungen

et al. 1986

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Based on results from measurements of arterial blood velocity, arterial and venous diameters of major segmental retinal vessels in normal persons and in patients with venous occlusive diseases and in continuation of the two preceding parts of this series of articles, further possibilities for the differential diagnosis of measurements of retinal microcirculation magnitudes are discussed. Whereas the measurement of blood velocity is an important criterion for the assessment of the stasis conditions and the arterial involvement in an occlusive disease, the diameters of the vessels offer essential suggestions to local regulative processes. In this connection, a dependence on pH of the contraction state of the smooth vascular musculature detected in porcine coronary arteries is presented. By its transmission to the arterial retinal vessels, it is possible to unequivocally clarify the local regulative and pathological behavior of arterial retinal vessels in terms of flow physiology.

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“…Untersuchungen zur Pathologie der retinalen Mikrozirkulation sind seit Langem Gegenstand internationaler Forschungen [7,12,14,17,18]. In grundlegenden Arbeiten wurde gezeigt, dass der Blutvolumendurchfluss bei Patienten mit diabetischer Retinopathie gegenüber Gesunden erhçht ist [8 -10, 13, 15, 16].…”

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