Long-term outcomes of inferomedial orbital wall decompression in Graves' ophthalmopathy in an Asian population: A 30-year retrospective study

Purpose: This study aims to evaluate the long-term outcomes of inferomedial orbital wall decompression (IMOD) in Graves' ophthalmopathy (GO). Methods: A retrospective review of 422 eyes of 226 patients with GO-related cosmetically disfiguring proptosis (COS), dysthyroid optic neuropathy (DON), or exposure keratopathy (EXP) who received IMOD from 1989 to 2020 was conducted. Hertel value (HE) and corrected visual acuity (CVA) were evaluated at baseline and regularly thereafter. Proptosis recurrence, diplopia, and adjuvant surgeries were assessed. Complete success was defined as proptosis reduction over 2 mm without recurrence and improved diplopia. Partial success was defined as proptosis reduction without recurrence but with persistent or new-onset diplopia, and failure as proptosis recurrence. Results: After follow-up for 40.1 +/- 39.6 months (range, 6-239 months), 236 eyes (55.9%) achieved complete success, 175 eyes (41.5%) achieved partial success, and 11 eyes (2.6%) had failure. Significant CVA improvement was observed in both DON and COS groups (P < 0.001 and P = 0.045, respectively). Average proptosis reduction was 5.2 +/- 2.2 mm, with a significant increase of 0.5 mm after long-term follow-up (P < 0.001). Incidence of proptosis recurrence was 2.6%. Surgical success rate of COS group was positively correlated with preoperative HE. Conclusion: IMOD demonstrated excellent success rate in all three subgroups with a low proptosis recurrence rate and improved visual outcome in both DON and COS groups. Delayed proptosis reduction effect of IMOD may result in delayed-onset asymmetry, especially in the unilateral group.