But it reminded me of the difference between the sclera and cornea. Both are made of the same collagen fibers. But in the cornea, the fibers are arranged in parallel sheets. Also to let the wavelengths of light there, there needs to be a smaller gap between these sheets, which requires relatively less hydration. Cloudy corneas arise from the inability of certain cells to pump water out of the stroma (collagen) layer in the cornea.

Anyway, it is pretty cool how it all works.