Changes in lens transmittance with aging and predicted impact on non-visual spectral sensitivity to light.

<p><b>A.</b> Transmittance spectra of the ocular lens in the young (n = 8, red line), and older subjects (n = 8, blue line). Filtering is particularly pronounced in the short to medium wavelength range (<530 nm) in the old compared to young subjects. Symbols on the curves indicate the average lens transmittance at 480 nm in the young (blue circle, 74.4%) and in the old subjects (red circle, 42.9%). An average decreased transmittance by 42.3% is found between young and old. <b>B.</b> real melatonin suppression spectrum in young subjects (blue line), and predicted melatonin suppression spectrum in the older subjects based on their decreased lens transmittance (red dashed line). Note the expected decreased melatonin suppression to short wavelength lights in the elderly and the shift in peak sensitivity to light from 484 nm to 497 nm. A 34% attenuation in melatonin suppression is predicted at 480 nm (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0085837#pone.0085837.s002" target="_blank">Figure S2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0085837#pone.0085837.s003" target="_blank">File S1</a> for details).