Basic question: is lens fungus any one particular species, such as has been observed for contact lenses, or is it a variety of opportunistic fungi? I'm curious as to whether etching the glass is a byproduct, or whether it's actually solubilizing the silica for its own purposes.
Fparnold,
I'm not entirely sure the fungus actually etches the glass or the coatings of cement used to assemble the groups. Over the years I've cleaned quite a bit of fungus from lenses & have not seen etched glass. I have had to recement a couple of pieces & it's kind of a pita. I have also removed internal coatings to get rid of the stuff with no complaints.
Having seen lichen growing on quartz crystals, nothing really surprises me where fungi are involved. If a lichen (which is a sumbiosis between a fungus and an alga) can etch quartz...