D2-40 expression demonstrates lymphatic vessel characteristics in the dural portion of the optic nerve sheath.

Purpose: To investigate the presence or absence of lymphatic vessels in the human optic nerve by means of immunohistochemistry.

Methods: Use of selective molecular markers to differentiate lymphatics from blood vessels in optic nerve specimens obtained after enucleation or exenteration procedures. Specifically, the lymphatic-specific monoclonal antibody D2-40 was used to identify lymphatic endothelial cells in contrast to CD-34 identification of endothelial cells of blood vessels.