Residual Apical Lamina Papyracea as a Cause for Persistent Dysthyroid Optic Neuropathy After Orbital Decompression

Two patients had persistent compressive dysthyroid optic neuropathy after decompression of the medial orbital wall and floor. In both cases, there was similar to 3 mm of unresected lamina papyracea anterior to the Annulus of Zinn, and removal of this residual bone led to resolution of the neuropathy. These illustrative cases suggest that, in some patients, even small amounts of residual crowding at the orbital apex can critically embarrass optic nerve perfusion, with resulting continued ischemic optic neuropathy.