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I. V. Ermakov, W. Gellermann; Fundus Camera Interfaced Raman Instrument for Measurement of Macular Pigment. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2136.
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© ARVO (1962-2015); The Authors (2016-present)
Resonance Raman spectroscopy is a highly molecule specific and rapid method for the detection of macular pigment, MP, in retinal tissues. Raman detection of MP does not reference foveal MP measurements to the retinal periphery. Therefore the method may have advantages over less specific alternative methods and methods that require a normalization of MP measurements to the peripheral retina. To facilitate Raman measurements of MP in elderly human subjects, in human subjects with retinal pathologies, and in primate eyes, we developed a fundus camera interfaced instrument that allows an operator to independently select the measured subject's retinal areas of interest.
The front end of a commercial, wide angle, fundus camera was interfaced with an optical light excitation and collection module of a Raman spectrometer, and the viewing port of the camera was interfaced with a video camera. Using suitable filters, the subject’s retina can be illuminated with white light and viewed on a TV monitor. Both provisions allow the operator to quickly locate the macula for subsequent MP Raman measurements, which are carried out within a fraction of a second. Purkinje imaging was employed to adjust the Raman response for ocular media opacities.
The instrument significantly improves the measurement accuracy for subjects with retinal pathologies such as age-related macular degeneration patients. Achievable MP level repeatability for young subjects was found to be similar to MP Raman measurements taken without additional fundus camera targeting. Video recording of the alignment procedure provides a useful record of the measurements.
Fundus camera interfacing of MP Raman measurements allows one to avoid potential problems with subjects not able to self-align such as patients suffering from macular pathologies. Therefore this instrument holds promise as a useful research tool for MP properties and their changes in the aging macula.
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