Compared to Trabeculectomy, Ex-Press® Surgery Significantly Decreased the Loss of Corneal Endothelial Cell Density in Low-Intraocular-Pressure Glaucoma: 3-Year Follow-Up

Purpose: We compared the corneal endothelial cell loss between trabeculectomy (Trab) and Ex-Press® surgery (EXP) for low-intraocular pressure (IOP) glaucoma patients. Patients and Methods: This was a single-facility retrospective study. We analyzed the cases of patients with primary open-angle glaucoma (POAG) and pre-operative IOP ≤ 21 mmHg who had undergone Trab or EXP surgery and were followed for >3 years. Noncontact specular microscopy was used to determine the corneal endothelial cell density (CED) before and after Trab or EXP surgery. We measured the CED at 12, 24, and 36 months post-surgery. We compared the CED values and CED survival ratio after both surgeries using paired t-tests. Results: We included 39 eyes that underwent Trab and 36 eyes that underwent EXP surgery. In the Trab group, the mean CED value had decreased from 2333 ± 399 at baseline to 2066 ± 587 cells/mm2 after 3 years. In the EXP group, the mean CED value had decreased from 2320 ± 393 at baseline to 2229 ± 460 cells/mm² after 3 years. The survival ratio of CED at >3 years was 89.3 ± 14.2% (Trab group) and 95.6 ± 11.1% (EXP group); compared to the Trab surgery, the EXP surgery thus significantly decreased the CED loss (p = 0.037). No case resulted in bullous keratopathy. Conclusion: Compared to trabeculectomy, Ex-Press® surgery appears to be a safer surgical method with regard to the endothelial cell loss risk.