Analysis of clinical features and outcomes in patients with ocular myasthenia gravis according to anti-acetylcholine receptor antibody-seropositivity: a retrospective cohort study

Abstract Purpose: To comparatively analyze the clinical characteristics of patients with ocular myasthenia gravis (OMG) who were referred to an ophthalmology clinic, according to anti-acetylcholine receptor antibody (AchR Ab)-seropositivity. Methods: Medical records of patients with OMG who presented to a tertiary eye care center between 2003 and 2020 were retrospectively reviewed. Demographics, ophthalmologic characteristics, response to medical treatment, presence of autoimmune thyroid disease and thyroid autoantibody were compared between the AchR Ab seropositive and seronegative groups. Results: A total of 130 patients with OMG were identified; among them, 46 patients (35.4%) had autoantibody against acetylcholine receptors. The mean age at symptom onset was 42.4±18.9 years. There were no differences in mean age at symptom onset, gender ratio, and mean follow-up period between patients with seropositive and seronegative OMG. Graves ophthalmopathy was significantly more frequent in seronegative patients (p=0.04), while thymic disease (p<0.01) was in seropositive patients (p<0.01). Among patients with seropositive OMG, 52.3% showed a good response to medical treatment, while only 31.4% of the seronegative patients were classified as good responders (p=0.01). Thyroid dysfunction was found in 27.4% patients with OMG and the proportion of thyroid dysfunction was not different according to anti-acetylcholine receptor antibody-seropositivity. Conclusion: Seropositivity to acetylcholine receptor antibody is associated with a better response to medical treatment and lower risk of concomitant autoimmune thyroid disease in patients with OMG.