Surgical Outcomes of Standardized Endoscopical Deep Medial Orbital Decompression in Dysthyroid Optic Neuropathy

Introduction: The aim of the study was to standardize the endoscopic deep medial orbital decompression surgery for better relief of optic nerve compression in dysthyroid optic neuropathy (DON). Methods: A total of 128 eyes from patients received the standardized endoscopic deep medial orbital decompression surgery were recruited in this study. The efficacy of the procedure was assessed at a 1-month follow-up by the best-corrected visual acuity (VA), visual field (VF), and visual evoked potential (VEP). Clinical data were collected to explore the factors that affected visual recovery. Oxygen saturation of retinal blood vessels, retinal thickness, and vessel density were measured to demonstrate the potential recovery mechanisms. Results: After surgery, the ratio of extraocular muscle volume in the orbital apex to orbital apex volume significantly decreased from 44.32 +/- 22.31% to 36.82 +/- 12.02% (p < 0.001). 96.87% of eyes' final VA improved; average VA improved from 0.93 +/- 0.73 to 0.50 +/- 0.60 at 1 week (p < 0.001) and 0.40 +/- 0.53 at 1 month (p < 0.001). Postoperatively, VF and VEP also improved, the oxygen saturation of retinal arteries increased, and the retinal thickness was reduced. Preoperative VA, visual impairment duration, and clinical activity score evaluation were associated with visual recovery. Conclusion: In this study, we standardized the endoscopic deep medial orbital decompression, of which key point was to relieve pressure in the orbital apex and achieved satisfactory visual recovery in DON patients.