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P.-J. Bernard, V. Vucea, V. Diaconu, IV; Foveolar Choroidal Blood Oxygeantion Assessed by Multichannel Spectroreflectometry. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4139.
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© ARVO (1962-2015); The Authors (2016-present)
Age related Macular Degeneration (AMD) is the principal cause of blindness in the world, affecting nearly 15 million people. There is consensus that the vascular problems and deficiencies of choroïdien blood contribution are important in AMD (Snow & Seddon 1999, Feigl 2007). The goal of this study was to explore the human fovea capillaries by the multichannel spectroreflectometry technique, to derive the relative oxyhemoglobin, hemoglobin and capillary blood content as a function of three levels of retinal illumination.
The full spectrum (430 - 650nm) reflectometry measurements were performed with a version of the "On line Spectroreflectometry Oxygenation Measurement in the Eye" instrument (OSOME Faubert & Diaconu US Patent # 5,919,132). Based on a model of optical reflectance and absorbance of different biological layers, we derived the optical density of oxyhemoglobin, haemoglobin, macula pigment and L- M- cones photo pigment from the fovea retinal zone. Twelve young subjects between 19 and 24 years old participated in the experiment. The spectral reflection was then recorded 360 seconds on line from the fovea retinal zone of every subject for three consecutive stationary light intensities of retinal illumination.
The results demonstrate that each level of retinal illumination induced changes in photo pigment optical density and capillary blood content. The changes in photo pigment optical density become stationary after 4-5 seconds subsequent to increasing retinal illumination. By growing the level of retinal illumination we record a progressive reduction in fovea blood contents. The fovea blood contents become stationary after 60 seconds subsequent to changes of retinal illumination.
By full spectrum fovea reflectometry measurements technique we detect the blood content changes as a function of retinal illumination. This method can be useful to establish vascular deficiency in human fovea capillaries.
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