Thymectomy in Ocular Myasthenia Gravis: Results Before and After Generalization and Prognostic Predictors of Outcomes

Background: The role of thymectomy in ocular myasthenia gravis (OMG) remains controversial, particularly before secondary generalization. Methods: We conducted a multicenter retrospective study on 174 OMG patients who underwent thymectomy (112 OMG, 62 generalized OMG [g-OMG]). The primary endpoint was complete stable remission (CSR; MGFA-PIS criteria). Multivariable analyses identified predictors of CSR and generalization. Results: Mean age at surgery was 42.3 ± 13.0 years; 53.4% were male. Thymoma was present in 29.3%. CSR was achieved in 18.9% overall, significantly higher in OMG (23.2%) compared to g-OMG (11.3%, p = 0.036), with 5-year CSR probabilities of 43% vs. 22% (p = 0.017). In non-thymomatous patients, 5-year CSR remained higher in OMG (41% vs. 17%, p = 0.010). Postoperative myasthenic crisis occurred exclusively in g-OMG (8.1%, p = 0.004). Multivariable analysis identified preoperative cholinesterase inhibitor monotherapy as an independent predictor of CSR (HR = 31.776, 95% CI: 4.188–241.111, p = 0.001; non-thymomatous: HR = 19.746, 95% CI: 2.518–154.849, p = 0.005). Minimally invasive techniques (78.6%) were associated with low morbidity (5.2%). Conclusions: Thymectomy during the purely ocular stage is associated with higher CSR rates and lower perioperative neurological risk than after generalization, particularly in non-thymomatous disease. Use of cholinesterase inhibitors as sole therapy prior to thymectomy independently predicts CSR. These findings support earlier surgical consideration in selected OMG patients and highlight the safety of minimally invasive approaches.