January 1985
Volume 26, Issue 1
Articles  |   January 1985
Fluorescence/Raman intensity ratio for monitoring the pathologic state of human lens.
Investigative Ophthalmology & Visual Science January 1985, Vol.26, 97-101. doi:
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      N T Yu, M Bando, J F Kuck; Fluorescence/Raman intensity ratio for monitoring the pathologic state of human lens.. Invest. Ophthalmol. Vis. Sci. 1985;26(1):97-101.

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      © ARVO (1962-2015); The Authors (2016-present)

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The authors have put quantitation of human lens fluorescence on a rational basis by using the accompanying Raman signal from lens protein as a normalization factor. The intensity ratio, Fluorescence/Raman (F/R), may be used to compare lenses of different ages when the exciting wavelength is long enough to give a measurable Raman signal. In younger lenses excited at 457.9 or 514.5 nm, the F/R shows a log increase with age. Older lenses, above 60 years of age, excited at 647.1 nm give a steeply rising sigmoid curve. In developing this procedure, the authors found that for each lens there is a characteristic wavelength that is called the critical wavelength (lambda critical). At wavelengths longer than lambda critical the Raman signal appears in the absence of a broad fluorescence peak; at shorter wavelengths the fluorescence intensity increases enough to overwhelm the Raman signal. For normal lenses, clear and not heavily pigmented, the lambda critical is age dependent, giving a curve that is a flattened sigmoid approximating a straight line.


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