Kahook Dual Blade versus Trabectome (KVT): Comparing Outcomes in Combination with Cataract Surgery

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 (μLOT-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 μLOT-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 μLOT-Phaco and KDB-Phaco patients. Results suggest that patients with higher preoperative IOP may have better postoperative outcomes.

Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges

The development of minimally invasive glaucoma surgeries (MIGSs) was intended to provide safe and modestly efficacious modalities for early intervention of mild-to-moderate glaucoma, with minimal trauma and rapid recovery. They were mainly ab interno procedures that reduce intraocular pressure by facilitating the aqueous outflow by bypassing the trabecular meshwork resistance, reinforcing the uveoscleral flow via the supraciliary space, and reducing aqueous production by the ciliary body. While the cumulating evidence helps shape the role of the available MIGS, the exponential new development and advancement in this field has expanded the territory of MIGS. Apart from developing subconjunctival MIGS filtration devices (Xen gel stent and PRESERFLO MicroShunt), there is a tendency to revisit the "traditional" MIGS for alternative use and to modify the procedures with consideration of the fundamental aqueous outflow physiology. Combined MIGS has also been suggested, based on the theory that their different mechanisms may provide additive or synergistic effects. The advancement of laser procedures is also promising and could supplement unmet needs along the glaucoma treatment algorithm. This review examines the broad array of MIGS, updates the recent findings, discusses their potential alternative applications, and explores future challenges.

Minimally Invasive Glaucoma Surgery: A Review of the Literature

Minimally invasive glaucoma surgery (MIGS) has emerged as a novel approach in the glaucoma treatment spectrum, offering a range of diverse procedures and devices aimed at reducing intraocular pressure (IOP). MIGS can be broadly classified into several categories: those that enhance trabecular outflow (Trabectome, iStent, Hydrus Microstent, Kahook Dual Blade, high frequency deep sclerotomy, and gonioscopy-assisted transluminal trabeculotomy), those that augment suprachoroidal outflow (CyPass Microstent and iStent Supra), those that target Schlemm's canal (TRAB360 and the OMNI Surgical System, Streamline, and Ab Interno Canaloplasty), and conjunctival bleb-forming procedures (EX-PRESS Glaucoma Filtration Device, Xen Gel Stent and PreserFlo MicroShunt). MIGS is considered to have a shorter surgical time and fewer severe complications when compared to traditional glaucoma surgeries such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves). This literature review comprehensively examines the distinct MIGS devices and procedures, their underlying mechanisms, and clinical outcomes, emphasizing the importance of evaluating the efficacy and complications of each approach individually. As the field of MIGS continues to evolve, it is crucial to prioritize high-quality, long-term studies to better understand the safety and effectiveness of these innovative interventions in glaucoma management.