ABSTRACT: Purpose:To investigate the synergic effect of combination of orbital decompression surgery and methylprednisolone pulse therapy (MPT) and MPT alone on the visual function in patients with bilateral dysthyroid optic neuropathy (DON). Methods:For each involved patient with bilateral DON, only one eye was treated with orbital decompression surgery which was conducted by the same doctor, and each of them received MPT after surgery. If the visual function deteriorated despite treatment, patients would switch to the other treatment. All the patients were followed up for 3 months after surgery. Clinical features of patients including best corrected visual acuity (BCVA), intraocular pressure (IOP), proptosis, upper eyelid retraction, and clinical activity score (CAS) before and after surgery were analyzed, respectively. Visual field and visual evoked potential (VEP) tests were also performed. Paired t-test and Wilcoxon matched-pairs signed ranks sum test were used to analyze the data. Result:A prospective cohort of 23 patients with bilateral DON was enrolled in this cohort study. No patients failed to the therapy or switched to another treatment. The quantitative variables were shown as means and standard deviations (SD). After 3 months of combined treatment of orbital decompression surgery and MPT, BCVA (logMAR) improved, proptosis was reduced and the upper eyelid retraction was relieved in both eyes of patients; however, these improvements were more significant in the operated eyes than in the fellow (nonoperated) eyes. IOP decreased significantly in the operated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (P=0.002), while having no significant change in the nonoperated eyes (. Conclusion:A combination of orbital decompression and MPT can significantly improve visual function in patients with DON, reduce intraocular pressure, and relieve clinical symptoms such as upper eyelid retraction and proptosis, while MPT alone has a limited effect. For DON patients, orbital decompression should be performed promptly to improve the visual function.