The presence of foam at the canthus is thought to be pathognomonic for blepharitis. What is the direct etiology of the foam?
A.Mucin balls form from increased ocular surface shear forces exerted by the eyelids in dry eye
B.Increased lysozymes react with free radicals to produce a froth-like material
C.Tear film debris such as sloughed epithelial cellular material that is increased in dry eye
D.Bacterial lipases resulting from low-grade infection within the meibomian glands
E.A detergent effect from altered meibomian gland lipids"