Bozho Todorich, Paul Hahn

We aim to describe a mechanism of vision loss following vitrectomy surgery with retrobulbar block (RBB) associated with severe vascular stasis of the optic nerve and macula in order to improve safety of local anesthesia for ophthalmic surgery. We report three cases of patients who underwent pars plana vitrectomy (PPV) with retrobulbar anesthesia with no retrobulbar hemorrhage or elevated intraocular pressure (IOP). At the beginning, in each case, hypoperfusion of optic nerve and macula was noted. In the case of one patient with significant vasculopathic risk factors, the vascular stasis was severe, while in the other two cases, it was mild-to-moderate. In all cases, the perfusion of posterior pole began to improve almost immediately following the start of PPV. Because the IOP was not elevated and no retrobulbar hemorrhage was present, this suggested a compartment syndrome in the intraconal space. The patient with severe vascular stasis developed finger-counting vision but had normal postoperative angiogram findings and unrevealing cardiovascular workup. In the other two milder cases, the occurrence of ischemia was not visually significant. Intraoperative ischemia should be considered in all cases of unexplained vision loss after ophthalmic surgery using RBB. Attention to vasculopathic risk factors and intra-operative hemodynamic parameters, in addition to the use of parabulbar block, may avoid this complication and permanent vision loss.