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ESP 
The glaucoma it is one of the leading causes of blindness worldwide, and its management has evolved significantly. Today, minimally invasive glaucoma surgeries (MIGS and MEPS) offer safer and more effective alternatives to control intraocular pressure (IOP). This article explores the latest trends and technologies in the field, based on an analysis of the "SAMUR A-I #7: MIGS/MIBS SHOWDOWN" document, with a focus on IOP reduction, safety profile, and patient selection.
A Paradigm Shift in Glaucoma Treatment
Traditionally, the trabeculectomy has been the gold standard for surgical treatment of glaucoma. However, the current landscape has seen a "radical shift" toward less aggressive options. MIGS y MEPS they seek to reduce IOP to moderate ranges (between 10 and 16 mmHg) with a superior safety profile, offering a "much broader and generally safer therapeutic arsenal than trabeculectomy." The goal is to find the perfect balance between IOP reduction and safety, always selecting the ideal patient for each technique.
Flow Pathways and Specific Technologies in Glaucoma Surgery
Minimally invasive glaucoma surgeries are classified according to the flow pathway they seek to optimize:
1. Improvement of Trabecular Flow (Natural Route)
These techniques facilitate the exit of aqueous humor through its natural route: the schlemm's canal and the trabecular meshwork.
- Implants/Scaffolds:
- iStent Family: Implants designed to improve drainage. The latest versions allow for the placement of multiple iStents for greater effectiveness.
- Hydrus: A small scaffold inserted into Schlemm's canal to keep it open. Comparative data with the iStent have sparked debate about its superiority.
- Tissue Ablation/Cutting:
- Trabectome: Uses electrocautery to ablate trabecular tissue.
- Goniotomies with Blades (Kahook Dual Blade – KDB): They allow precise cutting of the fabric.
- Bang Bent of Internal Needle Goniotomy (BANG): An "ingenious and accessible" technique that uses a bent insulin needle to perform goniotomy. It stands out for its cost-effectiveness. In combination with the phacoemulsification (cataract surgery), has demonstrated a 27% reduction in IOP and a 55% reduction in medication use at 6 months.
- Extensive Trabeculotomies:
- Transillumination Assisted Goniotomy (TAG): A 360-degree trabeculotomy which opens the entire canal. It achieves "quite remarkable" IOP reductions of approximately 9.3 mmHg. However, it has the highest rate of transient hyphema (bleeding in the eye), almost 28%, due to the cutting of more tissue.
- OMNI: Combine canaloplasty and trabeculotomy.
- Internal AV Microhook: It has shown "36-month data", suggesting durability.
- HFDS: With "impressive 6-year results," which "gives confidence in its durability."
It is important to note that there is a clear "efficacy-safety balance": a greater intervention in the trabecular meshwork, as with GAT or Microhook, often entails a greater IOP reduction, but also a slightly increased risk of hyphema. In addition, if the Basal IOP is high, the reduction is usually greater in absolute numbers.
2. Suprachoroidal Flow
This path creates a alternative pathway between the choroid and the sclera.
- MiniJet: The device currently available for this route, with "5-year data" and a 38% reduction in IOP, in addition to a "good safety profile."
- Security Considerations (CyPass Lesson): Removal of the device CyPass due to long-term endothelial cell loss was a "hard lesson" on the importance of long-term follow-up. This emphasized that the design, material and monitoring of patients for years are vital. The success of the MiniJet suggests that the suprachoroidal approach is viable with the proper design.
3. Subconjunctival discharge (MIBS)
These techniques are more similar to trabeculectomy, as they create a filtration ampoule so that the aqueous humor drains into the subconjunctival space.
- Ex-Press Gel Stent, XEN63 and PreserFlo MicroShunt: They achieve "more powerful" IOP reductions, sometimes as much as 40-55%, approaching the results of trabeculectomy. (See the PresserFlo chapter by clicking here.) here)
- Blister Management: Unlike trabecular MIGS, success here depends on the healing of the external conjunctiva. It is frequently used mitomycin C to prevent excessive scarring and sometimes it is necessary to perform needling to keep the blister functional.
- Complication Profile: They introduce a different complication profile, with a lower risk of hyphema but a higher risk of blister-related problems, such as leakage, hypotonia, or, rarely, infection.
4. Reduction of aqueous humor production
These techniques act on the ciliary body, the "factory" of aqueous humor.
- Endoscopic Cyclophotocoagulation (ECP): It allows to visualize and treat the ciliary body internally.
- Micropuls TSPC: Performs the treatment externally, using a technology that seeks to be "gentler and safer" and less destructive than traditional cyclophotocoagulation. They are particularly useful in very advanced or refractory glaucomas.
Key Findings and Future Implications in Glaucoma
The field of minimally invasive glaucoma surgery has advanced considerably, offering new hope to patients:
- Wide and Safe Therapeutic Arsenal: Ophthalmologists have a "much broader therapeutic arsenal" at their disposal, which is generally safer than trabeculectomy for controlling IOP within moderate ranges (10-16 mmHg).
- Effectiveness-Safety Balance: It is essential to understand that more powerful techniques, such as GAT or MIBS, achieve greater IOP reductions but carry different risks (hyphema or bleb complications).
- Crucial Patient Selection: "Patient selection is crucial." Factors such as PIO basal, the state of the iridocorneal angle, the severity of glaucoma, the age and the presence of cataract are decisive. They are developing nomograms to assist in this decision-making.
- Long-Term Data and Durability: The experience with CyPass highlights the need for “long-term data always.” durability and the cost are essential factors in daily practice.
- Continuous Innovation: Innovation continues unabated, with examples such as BANK for its cost-effectiveness, MiniJet validating the suprachoroidal approach, and Micropuls improving safety.
Finally, the "final reflection" is raised: the role of the Artificial Intelligence (AI)AI could analyze various patient factors (OCT, medical history, genetics) to "refine our ability to predict who will respond best to which technique." This would lead to personalization of glaucoma surgery to a new level, with the ability to “predict individual response being the next big step.”
