title: Indirect spectral transmission ratio measurements of the aging crystalline lens nucleus.
abstract: A new objective approach to characterize color and opalescence in the lens nucleus, using wavelength indexed transmission ratios (TR) is described. Transmission ratios, i.e. the transmissivity per unit lens thickness, for the whole visible spectral range (390-720 nm) were calculated using fast scanning spectral colorimetry (FSSC). The lowest transmission ratios values were obtained in the blue part of the spectrum in general and at 450 nm in particular. They inversely followed the subjectively determined LOCS II color grading. The difference between transmission ratios at the absorbed part of the spectrum (less than 500 nm) and the non-absorbed part (greater than 550 nm) also reflects the LOCS II color grading. The overall mean transmission ratios for all wavelengths in the spectrum gives an index that closely followed the nuclear opalescence grading of the LOCS II system. The transmission ratios are theoretically independent of the spectral characteristics of the incident light as long as it contains suprathreshold energies in the whole measured spectral range.
authors.affiliation: Center for Clinical Cataract Research, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: J H
authors.initials: JH
authors.lastname: Seland
authors.forename: L T
authors.initials: LT
authors.lastname: Chylack
authors.forename: J K
authors.initials: JK
authors.lastname: Wolfe
mesh_terms: D000042:Absorption; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003124:Colorimetry / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D007907:Lens Nucleus, Crystalline / Q000502:physiology* / Q000503:physiopathology; D008027:Light; D008297:Male; D008875:Middle Aged; D012016:Reference Values