Fenestrated connective tissue sheets, derived from the sclera as meridional extensions, form
the main support for the posterior portion of the lamina cribrosa. The sheets consist of a
dense collagenous tissue, often with elastic fibers, and in monkeys with pigment cells.
Astrocytes fill the spaces between successive sheets and line the rim of each fenestration.
Anteriorly, at the level of the choroid, the connective tissue elements disappear and the
lamina cribrosa becomes entirely glial. The anterior portion of the lamina cribrosa is an …