Light scattering model for donor lenses as a function of depth

The amount of light scattered by normal donor lenses (n = 15, ages 43-82 years) from a 1 x 0.1 mm white slit beam was measured as a function of depth in the lens for seven angles from 10 to 165 degrees, and for four wavelengths from 400 to 700 nm. Apart from the most superficial layers, the data could be described with a model that consisted of three components. (1) small sized protein particles (alpha-crystallin), (2) large sized protein particles and (3) spectrally neutral rough surface reflectance ('zones of discontinuity'). Component (1) and (3) dominate backward scattering. Component (2) dominates forward scattering, but occupies only around 0.000006 of the lens volume, with the lowest values in the nucleus. Component (3) is important for a small range of backward directions only, being much stronger in extranuclear areas than in the nucleus.