Lacrimal Trephine (Sisler). 21 G x 1 1/2″. Ultra sharp, micro trephine is useful for rotary trepanation of an obstructed canaliculus and for biopsy of the conjuctiva or sclera. Long enough to span the length of normal lacrimal canaliculus. Round, blunt tip stylet minimizes trauma to the surrounding tissue. 3/box.