title: Human lens transmission of blue light: a comparison of autofluorescence-based and direct spectral transmission determination.
abstract: OBJECTIVE
  Direct measurement of the transmission of light through the human lens is not possible in vivo unless invasive techniques are used. In the current study, a reliable in vivo estimate of the transmission of blue light through the lens was assessed by comparing an indirect and noninvasive method based on autofluorescence measurements with a direct method.
  
  
  METHODS
  Total transmission of blue light was measured in human donor lenses using a direct method applicable only in vitro and compared with transmittance estimates made by an in vivo applicable autofluorescence technique.
  
  
  RESULTS
  Human lens transmission of blue light decreases with age by 0.7-0.8% per year at 480 nm. The comparison of methods showed that the autofluorescence-based method correlated significantly with the direct measurements (R = 0.83, p < 0.001) and acceptable agreement between the two methods was found.
  
  
  CONCLUSIONS
  In conclusion, the human lens transmittance of blue light can be measured reliably in vivo. This enables the possibility to correct for retinal light intensities when studying the mechanisms of the circadian rhythm in clinical studies and related disorders and in addition when working with clinical and experimental methods affected by retinal blue light intensities.
authors.affiliation: Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Copenhagen, Denmark. adam@eliaz.dk
authors.forename: Adam Elias
authors.initials: AE
authors.lastname: Broendsted
authors.forename: Michael Stormly
authors.initials: MS
authors.lastname: Hansen
authors.forename: Henrik
authors.initials: H
authors.lastname: Lund-Andersen
authors.forename: Birgit
authors.initials: B
authors.lastname: Sander
authors.forename: Line
authors.initials: L
authors.lastname: Kessel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007908:Lens, Crystalline / Q000502:physiology*; D008027:Light; D008297:Male; D008875:Middle Aged; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D055815:Young Adult