21 July 1994 In-vivo measurements of optical properties of the ocular lens
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Abstract
`Optical aging' of the lens of the eye results from the cumulative photochemical effects of ambient light exposures and may be exacerbated by any number of disease processes and exogenous agents including acute or chronic exposure to above- ambient levels of ultraviolet and/or blue light. This `optical aging' of the lens is manifested by increased scattering of visible light, increased absorption of short-visible wavelengths, and increased fluorescence emitted at short- to mid-visible wavelengths when irradiated with UV or blue light. With age and with or without exacerbating factors, the initially clear lens takes on an increasingly yellowish and ultimately brunescent coloration associated with cortical cataract. We conducted in vivo measurements of the lens fluorescence induced by UV and blue wavelengths. The fluorescence intensity was quantitated as a function of intensity of exciting light and excitation wavelength. It was shown that other `safe' blue laser exposures induced enough of a fluorescent veiling glare to imply interference with visual function. The visual deficit was objectively demonstrated by monitoring visual evoked potential amplitudes while subjects were irradiated with blue laser light. A related study demonstrated the utility of a prototype optical biopsy instrument as a diagnostic tool for assessing the optical properties of the lens. Optical signatures of individual lenses were characterized by compiling the backscatter and fluorescence spectra elicited by each of several exciting wavelengths. By examining the optical signatures of a population of approximately 100 human lenses, several metrics were chosen for gauging the optical quality of a given lens relative to the norm for the subject's chronological age. These metrics may serve to identify cases of accelerated `optical aging' and provide early evidence of cataract or other disease processes.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Joseph A. Zuclich, "In-vivo measurements of optical properties of the ocular lens", Proc. SPIE 2134, Laser-Tissue Interaction V; and Ultraviolet Radiation Hazards, (21 July 1994); doi: 10.1117/12.180828; https://doi.org/10.1117/12.180828
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