Exfoliation fibrils have a characteristic ultramicroscopic appearance. They are 20-30 nm thick with 10 nm subunits and may be 800 or 900 nm long. They sometimes have a characteristic banding periodicity of about 50 nm. The fibrils have been located in the lens capsule, zonular threads, iris, ciliary body and trabecular meshwork. Extraocular locations have also been found in conjunctival vessels and retroorbital tissue.