Comparison of 1-year effectiveness between phaco-microhook ab-interno trabeculotomy and phaco-iStent trabecular micro-bypass stent in primary open-angle glaucoma with low-teen intraocular pressure.

Purpose: To investigate the surgical effectiveness of combined cataract surgery with microhook ab-interno trabeculotomy (phaco-µLOT) or iStent trabecular micro-bypass stent (phaco-iStent) in eyes with primary open-angle glaucoma (POAG) and preoperative intraocular pressure (IOP) controlled below 15 mmHg (low-teen IOP).

Methods: This retrospective cohort study included consecutive patients with POAG and low-teen IOP who underwent phaco-µLOT or phaco-iStent as their initial glaucoma surgery and were followed up for 1 year postoperatively. Surgical failure was defined as the inability to achieve the following criteria twice in a row: (A) IOP of 6-15 mmHg with over 20% IOP reduction; (B) IOP of 6-12 mmHg with over 20% IOP reduction.

Results: A total of 75 eyes from 75 subjects were included, with 48 in the phaco-µLOT group and 27 in the phaco-iStent group. The mean preoperative IOP and number of antiglaucoma medications were 13.1 ± 2.1 mmHg and 3.4 ± 0.9 in the phaco-µLOT group, and 12.6 ± 2.0 mmHg and 2.5 ± 1.2 in the phaco-iStent group, respectively. The number of antiglaucoma medications was significantly reduced to 2.5 ± 0.9 (phaco-µLOT) and 2.0 ± 1.1 (phaco-iStent) at 1-year postoperatively (all p < 0.05). For criteria A and B, the survival rates were significantly higher in the phaco-µLOT group than in the phaco-iStent group (all p < 0.01).

Conclusion: Both phaco-µLOT and phaco-iStent hold promise in reducing the need for antiglaucoma medications in POAG eyes with low-teen IOP. Phaco-µLOT may be more effective than phaco-iStent in controlling IOP.

Key messages: What is known Minimally invasive glaucoma surgeries (MIGS) procedures target the pressure gradient pathways in patients with higher preoperative intraocular pressure (IOP) levels, however, evidence on their effectiveness in normotensive glaucoma patients remains limited. What is new Combined cataract surgery with microhook ab-interno trabeculotomy (phaco-µLOT) or iStent trabecular micro-bypass stent (phaco-iStent) significantly reduced the number of antiglaucoma medications in primary open-angle glaucoma (POAG) eyes with preoperative IOP controlled below 15 mmHg (low-teen IOP). Phaco-µLOT may be more effective than phaco-iStent in controlling IOP. These procedures should be limited to reducing the number of antiglaucoma medications used, as they did not significantly reduce the postoperative IOP in POAG eyes with low-teen IOP.