Compact Laser Doppler Choroidal Flowmeter

Geiser, Martial; Diermann, Ulrich; Riva, Charles E.

doi:10.1117/1.429960

Cited by 52 publications

(58 citation statements)

References 7 publications

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“…Ray I s represents one of the scattering components with a deviation angle of θ 1 relative to the direction of the ray donated by I s , and a deviation angle of θ 2 relative to the direction of the z-axis. Doppler frequency shift achieved in ray I s corresponding to ray I i based on previous ray tracing is then given by [14][15][16] …”

Section: Theoretical Analysis 31 Ray Trace Modelmentioning

confidence: 99%

Choroidal laser Doppler flowmeter with enhanced sensitivity based on a scattering plate

et al. 2011

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Section: Theoretical Analysis 31 Ray Trace Modelmentioning

confidence: 99%

Choroidal laser Doppler flowmeter with enhanced sensitivity based on a scattering plate

et al. 2011

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“…In our study, a compact laser Doppler flowmeter, which has been described in detail previously, 33,34 was used for the ChBF measurements. Measurements were performed in the fovea by asking the subject to fixate directly at the beam.…”

Section: Measurementsmentioning

confidence: 99%

Comparison of Choroidal and Optic Nerve Head Blood Flow Regulation during Changes in Ocular Perfusion Pressure

Schmidl¹,

Boltz

Kaya³

et al. 2012

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. We compared the response of choroidal and optic nerve head blood flow (ChBF, ONHBF) in response to an increase in ocular perfusion pressure (OPP) during isometric exercise and during a decrease in OPP during an artificial increase in intraocular pressure (IOP). METHODS.We included 96 healthy subjects in our study. In 48 subjects OPP was increased by 6 minutes of squatting, and either ONHBF (n ¼ 24) or ChBF (n ¼ 24) was measured continuously. In 48 other healthy subjects either ONHBF (n ¼ 24) or ChBF (n ¼ 24) was measured continuously during a period of artificial increase in IOP using a suction cup. All blood flow measurements were done using laser Doppler flowmetry. RESULTS.During all experiments the response in blood flow was less pronounced than the response in OPP, indicating for flow regulation. During isometric exercise ChBF regulated better than ONHBF (P ¼ 0.023). During artificial IOP increase ONHBF regulated better than ChBF (P ¼ 0.001). Interindividual variability in blood flow responses was high. During squatting ONHBF decreased considerably below baseline ONHBF when OPP fluctuated in 3 subjects, although OPP still was much higher than at baseline. This phenomenon was not observed in the choroid. CONCLUSIONS.Our data indicate that regulation of ChBF and ONHBF during changes in OPP is different and complex. In some subjects performing squatting, considerable ONHBF reductions were observed during OPP fluctuations, although OPP still was high. Whether this predisposes to ocular disease remains unclear. (Invest Ophthalmol Vis Sci. 2012;53:4337-4346)

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“…12 The sensitivity of the LDF measurements in AMD eyes of this study was consistent with that described in healthy eyes using the same device. 7,13,14 The calculation of the sensitivity is bound to an experience and not to the instrument. It gives the minimum variation of a parameter that is statistically significant in response to a given stimulus (PDT in this experiment) for a given population of patients.…”

Section: Discussionmentioning

confidence: 99%

“…Subfoveal blood flow after photodynamic therapy V Vinh Moreau-Gaudry et al elsewhere, 7 and we give here only a brief summary. It is based on the fact that reflected light on moving red blood cells (RBCs) will shift in frequency (Doppler effect).…”

Section: Choroidal Blood Flowmentioning

confidence: 99%

Effects of photodynamic therapy on subfoveal blood flow in neovascular age-related macular degeneration patients

Moreau-Gaudry

Geiser

Romanet

et al. 2009

Eye

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Aim To assess the short-term changes in choroidal blood flow (ChBF) after photodynamic therapy (PDT) in patients with neovascular age-related macular degeneration (AMD). Methods Fourteen patients with exudative AMD were included after a complete ophthalmological examination, fluorescein and indocyanine green angiography and optical coherence tomography. Subfoveal ChBF was assessed using laser Doppler flowmetry (LDF) in both treated (n ¼ 14) and nontreated contralateral (n ¼ 8) eyes, 1 h and 1 week after PDT. Ocular perfusion pressure was calculated. Results The detection sensitivity of the LDF measurements at 2-min intervals before PDT in treated eyes was 7.4% for volume, 6.3% for velocity, and 10.4% for ChBF. The initial mean visual acuity was 0.68±0.3 logMar. Macular thickness at baseline as measured by OCT3 was at median (interquartile range), 326.5 lm (188-367). At 1 h and 7 days after PDT, a significant increase in velocity (15.8 and 24.4%, respectively) and a significant decrease in volume (11 and 17.9%, respectively) were noted in treated eyes. Choroidal blood flow and ocular perfusion pressure (OPP) remained similar during follow-up. No significant change in flow parameters was reported in untreated eyes. Conclusion The LDF technique provides feasible and reliable measurements of blood flow parameters before and after PDT in a selective population of patients with exudative AMD. The prognostic value of these early blood flow parameter changes also needs to be assessed.

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Compact Laser Doppler Choroidal Flowmeter

Cited by 52 publications

References 7 publications

Choroidal laser Doppler flowmeter with enhanced sensitivity based on a scattering plate

Choroidal laser Doppler flowmeter with enhanced sensitivity based on a scattering plate

Comparison of Choroidal and Optic Nerve Head Blood Flow Regulation during Changes in Ocular Perfusion Pressure

Effects of photodynamic therapy on subfoveal blood flow in neovascular age-related macular degeneration patients

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