Selective endoscopic decompression of the orbital apex for dysthyroid optic neuropathy

Objectives/Hypothesis: To introduce the concept of selective endoscopic decompression of the orbital apex for dysthyroid optic neuropathy and present surgical outcomes. Study Design: Prospective case series. Methods: Consecutive patients undergoing urgent endoscopic orbital apex decompression for dysthyroid optic neuropathy were studied prospectively. Surgical indications consisted of retrobulbar optic neuropathy with radiologic evidence of apical crowding in the setting of Graves' disease. Pre-and postoperative parameters assessed included exophthalmometry, visual acuity, presence or absence of exposure keratitis, diplopia, an afferent papillary defect, and Ishihara color plate testing. Results: In all patients, visual acuity was improved or was stabilized by selective orbital apex decompression. Preoperative afferent papillary defects were reversed in all but one patient. Patients with decreased color vision by Ishihara color plate testing had postoperative improvement in their scores. No patients developed postoperative diplopia. An average of 3.1 mm of ocular recession was achieved. Conclusions: Selective decompression of the orbital apex spares the anteromedial and inferior orbital walls that are typically removed in a standard endoscopic orbital decompression. This focused approach successfully addresses compressive optic neuropathy, while minimizing the risk of postoperative diplopia or delayed sinus outflow obstruction. In patients with progressing dysthyroid optic neuropathy without diplopia this modified procedure should be considered.