Measurements of retinal microcirculation in retinal vessel occlusion before and after treatment

Vilser, Walthard; Jütte, A; Seewald, D.; Dietze, U.; Friedrich, R; Königsdörffer, E.; Buchner, David M.

doi:10.1007/bf02141494

Cited by 8 publications

(4 citation statements)

References 9 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

203

240

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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

203

240

View full text Add to dashboard Cite

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“…(1996) suggested that circulation velocity increases in the areas with laser burns 3–9 months after laser treatment. Vilser et al. (1986) observed an increase in RBF after laser treatment but RBF did not reach normal values.…”

Section: Discussionmentioning

confidence: 98%

The capillary blood flow in ischaemic type central retinal vein occlusion: the effect of laser photocoagulation

Arvas

Ocakoğlu

Özkan

2002

Acta Ophthalmologica Scandinavica

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ABSTRACT. Purpose: To determine the effect of photocoagulation on retinal blood flow (RBF) in eyes with ischaemic type central retinal vein occlusion (CRVO). Patients and Methods:Retinal blood flow was measured in 12 eyes with CRVO, 12 fellow eyes and 12 eyes of 12 age-matched healthy subjects using the Heidelberg retinal flowmeter (HRF). Microvascular blood flow values (volume, flow, velocity) were recorded from the upper temporal retina and macula. Eyes were re-examined 1 month after photocoagulation. We investigated whether there was a difference in RBF measurements before and after photocoagulation treatment. Results: In eyes with CRVO, mean RBF values (volume, flow and velocity) obtained from the upper temporal retina increased significantly after treatment (paired t-test, p ∞ 0.05). In contrast, mean RBF values from the macula were unaffected by photocoagulation (paired t-test, p Ͼ 0.05). Retinal blood flow values from the upper temporal retina obtained from control subjects were significantly higher than the values in eyes with CRVO before and after photocoagulation (unpaired t-test, p ∞ 0.05), but there was no significant difference between control subjects and CRVO patients in RBF values from the macula (unpaired t-test, p Ͼ 0.05). Mean RBF values were significantly higher in CRVO patients' fellow-eyes before photocoagulation in the eyes with CRVO (paired ttest, p ∞ 0.05) but were lower than in age-matched healthy control eyes (unpaired t-test, p ∞ 0.05). Macular blood flow did not differ between the eyes with CRVO and fellow eyes (paired t-test, p Ͼ 0.05). Conclusion: Laser photocoagulation increased retinal blood flow in eyes with CRVO, but RBF did not reach normal values. Photocoagulation was found to have no effect on RBF in the macular area.

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“…On the other hand, Bertram and coworkers [22] observed that circulation velocity increases in the areas with laser burns 3-9 months after laser photocoagulation (PC). Similarly Vilser et al [23] showed an increase in retinal blood flow (RBF) after PC but RBF did not reach normal values. According to Arvas et al [24] study by Heidelberg retinal flowmetry (HRF) if the laser burns were not extensive; grade 2 and 3a burns do not damage the internal capillary plexus and this has even further positive effect on blood flow values.…”

mentioning

confidence: 90%

Laser Photocoagulation in Retinal Vein Occlusion

Altıntaş

2016

International Journal of Ophthalmic Research

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Retinal vein occlusion (RVO) is the second most common retinal vascular disease after diabetic retinopathy which is a frequently devastating cause of blindness in mainly in older patients over 60 years of age. Its prevalence changes according to studies in overall populations are from 5.2 to 16 per 1,000 [1][2][3][4] . People with end-organ damage caused by diabetes mellitus and hypertension have strongly increased risk for RVO. The majority of individual diagnosed with RVO defined more than one component of the systemic vascular and metabolic disease, such as the presence of Diabetes Mellitus, hyper tension and high serum lipids. Coexisting metabolic diseases are important factors for prognosis and laser treatment response [1][2][3][4][5] .There are mainly two types of RVO according to occlusion side branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). In BRVO occlusion is located in the any branch of the retinal vein system, while occlusion located exactly in the central retinal vein in CRVO. Different researches shows that BRVO is 4-6 times more common than CRVO and it has been estimated that there are around 80 new cases of CRVO/million population/ year. Although CRVO most commonly affects one eye, in around 10% of patients the disease affects both eyes [2][3][4][5][6][7] . Even RVO was first recognized over a century ago, the exact pathogenesis is not completely nderstood and therefore exact treatment methods not found yet. The condition may be due to a combination of three systemic changes known as Virchow's triad: (1) hemodynamic changes such as venous stasis; (2) degenerative changes of the vessel wall; and (3) blood hypercoagulability [6,8,9] . According to clinical findings, fundus appearance, Fluorescein angiography and electrophisiological results Hayreh futher divided RVO into three types: (1) BRVO is divided further into major BRVO (a) and macular BRVO (b) according to localization; (2) CRVO is divided into ischemic and non-ischemic types due to presence or absence of ABSTRACTVisual acuity is primarily decreased secondary to macular edema, retinal ischemia and complications of neovascularisation in both BRVO and CRVO. Panretinal Laser photocoagulation or Focal photocoagulation is an effecting treatment for neovascularisation and prevention of complications of neovascularisation by ablating ischemic retina in either BRVO or CRVO. But Macular Laser photocoagulation can be use for treatment of non ischaemic macular oedema in only BRVO either alone or combination with other Anti-VEGF or Anti-inflammatory medication.

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Measurements of retinal microcirculation in retinal vessel occlusion before and after treatment

Cited by 8 publications

References 9 publications

Towards metabolic mapping of the human retina

Towards metabolic mapping of the human retina

The capillary blood flow in ischaemic type central retinal vein occlusion: the effect of laser photocoagulation

Laser Photocoagulation in Retinal Vein Occlusion

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