Speaker - Julian Garcia-Feijo

Over the past 25 to 30 years, advancements in glaucoma treatment have significantly expanded, introducing various devices and techniques to reduce intraocular pressure (IOP). A clear distinction between Minimally Invasive Glaucoma Surgery (MIGS) and more aggressive platform-based procedures is crucial. The European Glaucoma Society (EGS) has produced an excellent guide that provides comprehensive data on these technologies. MIGS is often considered an intermediate option between medical therapy, laser treatments, and more invasive surgeries, especially beneficial for patients with both cataracts and early-stage glaucoma, allowing for a personalized, early intervention. While less aggressive than BLEB-forming surgeries like trabeculectomy, these devices aim to lower IOP and enhance long-term disease control, improving the quality of life for early-stage patients. However, MIGS may not be effective for advanced glaucoma, where more aggressive procedures are required. While MIGS has been available for 25 years with low complication rates, it is essential to refine surgical indications and techniques to ensure success, necessitating both careful preoperative assessment and acquiring new skills. 

Referring to the EGS guide is highly recommended for an in-depth understanding of the available treatment options. Among the minimally invasive techniques, trabecular stenting, such as iStent and Hydrus, is particularly effective for early-stage primary open-angle glaucoma (POAG) patients, especially with cataract surgery. The primary goal is to lower IOP and reduce dependence on medications, supported by substantial long-term data showing their efficacy when performed correctly. These procedures help achieve target IOP levels in the mid to high teens (14–18 mmHg), demonstrating success as combined and standalone interventions. Long-term results indicate sustained IOP control, with mean pressures around 16 mmHg, emphasizing the need to match the approach to patients requiring such target pressure levels. Moreover, there is increasing evidence that these trabecular devices can enhance the patient's quality of life, improving ocular symptoms and vision-related activities, particularly when performed as a combined surgery rather than cataract surgery alone. Another important benefit is the reduction in medication use post-surgery. Long-term studies suggest that these devices can slow disease progression, although the strength of evidence varies. Nevertheless, it aligns with current treatment objectives for glaucoma management. 

The analysis of randomized controlled trials revealed moderate to low evidence regarding the efficacy of combined procedures compared to cataract surgery alone. The findings indicated that patients undergoing combined treatment required fewer topical medications post-operatively, and IOP was significantly lower with these procedures than with phacoemulsification. While robust data supported these primary outcomes, there remained limited information on long-term quality of life and disease progression, necessitating further research due to the absence of high-quality, large-scale, randomized controlled trials. Various techniques were available for addressing the trabecular meshwork, including methods for cutting or ripping the tissue with instruments like a catheter hook or Trabectome, which, while more expensive, offered a cost-effective alternative through manual techniques. Laser interventions created openings in the trabecular meshwork, as illustrated in an accompanying video, and presented the advantage of not requiring device insertion into the anterior chamber, thereby minimizing device-related complications. Despite these methods, the comparative effectiveness of laser treatments versus other devices remained unclear due to a lack of comprehensive trials, limiting the ability to draw definitive conclusions about the superiority of one approach over another. Additionally, options such as canaloplasty and trabeculotomy were explored to enhance aqueous outflow by expanding Schlemm's canal, with several devices assisting in these procedures while avoiding implantable devices. However, the absence of robust comparative trials between interventions like iStent and canaloplasty devices underscored the critical need for further research to establish the most effective surgical strategies.

The suprachoroidal space presents another approach for lowering IOP, taking advantage of the significant pressure gradient in this area. In Europe, the Minijet device has shown promising efficacy, with one-year outcomes indicating stable pressures around 14 to 15 mmHg. While the Sarir procedure is more aggressive and typically indicated for more advanced cases, it may lead to complications, as discussed later. It is important to recognize that all surgical interventions, whether device-free or not, carry the risk of complications. Potential issues include severe bleeding, iris damage, hyphema, IOP spikes, and postoperative inflammation, making these surgeries not entirely free of risks. In summary, for trabecular devices, there is an approximately 80% chance that patients previously on two to three medications may not require additional treatment for the next few years, especially in early glaucoma cases. Improved quality of life may result from stable IOP control and reduced medication adherence challenges. Although these devices offer patients benefits such as medication-free periods and stable IOP, more evidence is needed to understand their comparative effectiveness fully. Proper indications and surgical techniques are crucial for achieving optimal outcomes. For cases requiring even lower IOP, more potent surgical options are necessary, with trabeculectomy still regarded as the gold standard. Other emerging devices, such as the Shen or pressure flow micro shunt, aim to create a BLEB and lower IOP effectively, further expanding the options for managing glaucoma.

The emergence of new devices, such as the Shen 63, offers an alternative approach for managing IOP, potentially providing lower pressures ranging from 12 to 15 mmHg. Long-term efficacy data for devices like the pressure flow micro shunt indicate a reduction in IOP to around 12 mmHg, which is suitable for many advanced cases. Additionally, these devices have been associated with decreased medication use, which is crucial for patient management. Notably, a study conducted in South America on a challenging population showed that many patients achieved complex success, with IOP levels between 6 and 14 mmHg. It highlights the potential effectiveness of these devices, even in difficult cases. To maximize the efficacy of these interventions, the dosing of mitomycin C (MMC) is vital; increased doses have been correlated with enhanced outcomes. Although the study was not designed to assess the dosage effect specifically, it revealed a trend indicating that higher doses, such as 0.4 mg, yielded better IOP control and more medication-free patients. It suggests that careful consideration of MMC dosing can significantly optimize the results of glaucoma surgeries using these newer devices.

In real-life scenarios, observations highlighted that increasing the dose of MMC reduced the failure rate of surgical interventions. While the analysis was not derived from a randomized controlled trial or a prospective study, it provided valuable insights into the relationship between MMC dosage and surgical outcomes. Compared to trabeculectomy using a lower MMC dose of 0.2 mg, which typically yielded IOP levels around 14 mmHg, this pressure was still adequate for many patients with moderate glaucoma despite being lower than trabeculectomy's 11 mmHg average. Importantly, the complication rates associated with these devices were lower than those seen with trabeculectomy. A randomized trial comparing trabeculectomy with pressure flow devices indicated no significant difference in endothelial cell count between the two groups after several years. It suggests device insertion into the anterior chamber does not adversely affect the corneal endothelium. However, achieving these results necessitated precise placement of the tube, ensuring it was adequately positioned away from the cornea. Careful placement is critical for maximizing the efficacy and safety of the surgical intervention. 

In summary, various techniques exist for managing intraocular pressure in glaucoma patients, including trabecular micro-bypass for early glaucoma, suprachoroidal approaches for high-risk cases, and BLEB-forming devices suitable for moderate to advanced glaucoma. When considering treatment for early glaucoma patients who also have cataracts, a combined procedure may effectively reduce or eliminate the need for medications. For more advanced glaucoma cases with insufficient IOP control, the choice of intervention should depend on the specific stage of the disease and desired IOP targets. While trabecular procedures may be appropriate for early-stage patients, BLEB-forming devices or conventional filtering surgeries are often indicated for advanced cases. It is crucial to match the chosen technique to the proper indications and to ensure that the surgical procedures are executed meticulously to achieve optimal outcomes. 

42nd Congress of the European Society of Cataract and Refractive Surgeons, 6 – 10 September 2024, Fira de Barcelona, Spain.