Risk factors for Ex-press® surgery failure

Purpose: To investigate the risk factors for Ex-Press® (EXP) surgery failure. Patients and Methods: This was a retrospective non-randomized study of 98 patients who had undergone EXP and were followed-up >5 years. We investigated the following nine risk factors: age, gender, hypertension, diabetes mellitus (DM), previous glaucoma surgery, type of glaucoma (primary open angle glaucoma vs. pseudo-exfoliation glaucoma), surgical methods (EXP alone vs. EXP+cataract surgery simultaneously), central corneal thickness (CCT), and preoperative intraocular pressure (IOP). We defined a successful surgery as a post-operative reduction in the IOP >20% from the preoperative IOP and <18 mmHg. We determined the risk factors using multivariate cox regression models. Results: : Performing EXP significantly decreased the IOP (pre-operative: 25.2 ± 8.7, at 5 years: 11.1 ± 4.1). The success ratio of EXP was 67.4% at 5 years. We found no significant risk factors for EXP surgery failure. The p-values of the factors were age (p=0.936), gender (p=0.0587), hypertension (p=0.409), DM (p=0.967), previous glaucoma surgery (p=0.940), type of glaucoma (p=0.435) surgical methods (p=0.521), CCT (p=0.091), and preoperative IOP (p=0.082). Conclusions: : No preoperative factors that could be used to predict the failure of EXP surgery were identified. EXP can be safely performed for various types of glaucoma.