A Retrospective Study of Risk Factors Affecting Long-Term Outcomes Following Ab Interno Trabeculotomy and Goniotomy Concomitant with Phacoemulsification

Purpose: To examine the potential risk factors affecting the long-term outcomes following a combination of phacoemulsification with ab interno trabeculotomy with the microhook (mu LOT-Phaco) and goniotomy with the Kahook Dual Blade (KDB-Phaco).Methods: For 12 months, we retrospectively examined a total of 100 eyes of 100 patients with primary open-angle glaucoma (POAG) and exfoliation glaucoma (EG) who had previously undergone surgery between December 2016 and December 2020. Patients with a preoperative intraocular pressure (IOP) <12 mmHg were excluded. Probability of success was calculated using the Kaplan-Meier method, with surgical failure defined as an IOP >18 mmHg, <20% IOP reduction or additional glaucoma surgery. The Cox proportional hazards model was used to examine the potential risk factors for failure, which included age, gender, type of glaucoma, surgical techniques, preoperative IOP, number and type of preoperative IOP-lowering medications, preoperative visual field mean deviation (MD) value, and axial length.Results: For the 51 males and 49 females, mean preoperative age was 74.4 +/- 9.0 years, with mu LOT-Phaco performed in 44 and KDB-Phaco in 56 subjects. The type of glaucoma was POAG in 68 and EG in 32 eyes. Preoperative IOP was 20.5 +/- 6.7 mmHg, while postoperative IOPs were 14.4 +/- 4.2 mmHg, 13.7 +/- 2.8 mmHg, and 14.6 +/- 3.9 mmHg, respectively (P < 0.001). Significant decreases from the preoperative number of IOP-lowering medications (3.1 +/- 1.2) were observed at 12, 24, and 36 months, respectively (1.2 +/- 1.3, 1.6 +/- 1.3, and 2.1 +/- 1.4 (P < 0.001)). Probability of success at 12, 24, and 36 months postoperatively was 52.0%, 49.6%, and 47.7%, respectively. Lower preoperative IOP was shown to be a potential risk factor for surgical failure.Conclusion: Long-term follow-ups showed IOP decreased in mu LOT-Phaco and KDB-Phaco patients. Results suggest that patients with higher preoperative IOP may have better postoperative outcomes.