ABSTRACT
BACKGROUND: Spectroscopic methods permit the non-invasive detection of fundus pigments by the wavelength-dependent absorption of fluorescence as well as by the fluorescence lifetime. From the relative concentrations of haemoglobin and oxyhaemoglobin, the oxygen saturation can be calculated. The onset of age-related maculopathy might be delayed by a high optical density of xanthophyll. The detection of alterations in fundus autofluorescence points to age-related pathomechanisms (accumulation of lipofuscin, formation of connective tissue). The detection of autofluorescence of redox-pairs of coenzymes results in information about metabolic states at the cellular level, and might make possible an early detection of age-related changes when they are still reversible. METHOD: The evaluation of reflectance spectra, detected by imaging ophthalmo-spectrometry, results in the calculation of oxygen saturation or in the optical density of xanthophyll or of melanin. Fluorescence spectra can be measured also by this technique. For the 2-dimensional determination of the distribution of xanthophyll, a very simple method was developed, requiring fundus illumination by one wavelength only. In the detection of time-resolved autofluorescence, the fluorescence lifetime is used for the determination of endogenous fluorophores. RESULTS: As result of comparing studies between ARM patients and healthy subjects, the consumption of retinal oxygen was increased already in the children of ARM patients. An increasing optical density of xanthophyll was determined after lutein supplementation. Differences in fluorescence lifetime were determined between ARM patients and healthy subjects, but their interpretation requires investigations of cell or of organ model cultures. CONCLUSIONS: The described methods permit in vivo basic investigations of ARM and can be considered as impulses for the development of diagnostic devices.
Subject(s)
Algorithms , Diagnosis, Computer-Assisted/methods , Fluorescein Angiography/methods , Macular Degeneration/diagnosis , Ophthalmoscopy/methods , Spectrometry, Fluorescence/methods , Adult , Aged , Aged, 80 and over , Biomarkers/analysis , Clinical Trials as Topic , Female , Humans , Male , Middle Aged , Reproducibility of Results , Sensitivity and Specificity , Xanthophylls/analysisABSTRACT
BACKGROUND: It is thought that a high optical density of xanthophyll has a protective effect against the development of aggregated macular degeneration. The aim of this study was to investigate whether an increase of the optical density of xanthophyll in the macula after a supplementation of lutein can be proven by objective methods. Most methods applied for the determination of the macular pigment require the co-operation of the proband and the ability for foveal fixation. METHOD: Imaging spectrometry and the evaluation of laser scanner images taken at 488 nm will be presented. In contrast to psychophysical methods, both methods are independent of the patients ability for foveal fixation. RESULTS: Even by evaluation of laser scanner images taken as in fluorescence angiography but without inserting the blocking filter, the 2-dimensional distribution of xanthophyll can be determined. In 10 probands taking 6 mg lutein daily over 40 days, an increase of the optical density could be determined at least in some probands. The optical density reached a plateau 30 days after starting the supplementation of lutein. CONCLUSION: The assumed protective effect of xanthophyll against age-related macular degeneration can be influenced by supplementation of lutein under objective control.
Subject(s)
Lutein/pharmacology , Macula Lutea/drug effects , Xanthophylls/metabolism , Adult , Female , Humans , Macula Lutea/pathology , Macular Degeneration/pathology , Macular Degeneration/prevention & control , Male , Microscopy, Confocal , Middle Aged , Ophthalmoscopy , Spectrum AnalysisABSTRACT
BACKGROUND: The aim of this study was to evaluate prospectively whether there are differences in spectrometrically measurable parameters of the fundus between patients with early and late age-related maculopathy (ARM), the children of the ARM patients (F1 generation) and normals. METHOD: Using the "Jenaer Imaging Spectrometer", retinal oxygen saturation, xanthophyll, and intrinsic fluorescence were measured; the spatial distribution of xanthophyll was determined using the Rodenstock SLO 101 model. RESULTS: Xanthophyll is reduced in late ARM as compared to the F1 generation and the control group (alpha < 0.01). The different fluorescence spectra, measured at shortwave and at longwave excitation, suggest the presence of more than one fluorophore. Furthermore, the components of the fluorophores seem to be different between patients with ARM and their F1 generation. The longwave autofluorescence is age-dependent only in late ARM (r2 = 0.81). For the first time, we found an alteration in oxygen saturation in retinal vessels in patients with ARM. CONCLUSIONS: Xanthophyll is reduced only in late ARM. Autofluorescence and oxygen saturation are different between ARM patients, the F1 generation and normals, however, we were not able to identify a genetically based predisposition concerning the parameters studied.
