Dr. Sasmita Das

Introduction

Glaucoma is a progressive optic neuropathy and a leading cause of irreversible blindness worldwide. While medical therapy and laser procedures remain the first line of treatment, surgical intervention becomes essential when intraocular pressure (IOP) remains uncontrolled or disease progression continues.

Over the last decade, glaucoma surgery has evolved significantly, moving from traditional filtering surgeries to safer, minimally invasive techniques that offer effective IOP control with faster recovery and fewer complications.

Conventional Glaucoma Surgeries

1. Trabeculectomy
Trabeculectomy remains the gold standard for achieving low target IOP, especially in advanced glaucoma.

Mechanism:
Creates a fistula for aqueous humor drainage into the subconjunctival space forming a filtering bleb.

Advantages:

• Powerful IOP lowering
• Suitable for advanced and refractory glaucoma

Limitations:

• Risk of hypotony, bleb leaks, infection
• Intensive postoperative care
• Long-term bleb-related complications

Antimetabolites such as Mitomycin C (MMC) have improved long-term success but increased bleb-related risks.

2. Glaucoma Drainage Devices (GDDs)
Includes Ahmed, Baerveldt, and Molteno implants.

Indications:

• Failed trabeculectomy
• Neovascular, uveitic, or secondary glaucomas

Advantages:

• Effective in complex cases
• Predictable IOP reduction

Complications:

• Tube exposure
• Corneal decompensation
• Hypertensive phase

Newer Surgical Advances in Glaucoma

1. Minimally Invasive Glaucoma Surgery (MIGS)
MIGS offers moderate IOP reduction with excellent safety and faster recovery.

a) Trabecular MIGS:

• iStent, Hydrus Microstent, Trabectome, Kahook Dual Blade (KDB)
• Mechanism: Enhances aqueous outflow via Schlemm’s canal
• Best suited for mild to moderate primary open-angle glaucoma, often combined with cataract surgery

b) Canal-Based Procedures:

• GATT (Gonioscopy-Assisted Transluminal Trabeculotomy), OMNI Surgical System
• Advantages: No bleb formation, preserves conjunctiva, effective in adult and pediatric glaucoma

c) Suprachoroidal Devices:

• Earlier: CyPass (withdrawn)
• Newer devices under evaluation aim to revive this pathway with improved safety

2. Subconjunctival MIGS:

• XEN Gel Stent, PreserFlo MicroShunt
• Mechanism: Creates a controlled subconjunctival drainage pathway
• Advantages: Lower IOP than trabecular MIGS, less invasive than trabeculectomy, more predictable bleb

3. Advances in Surgical Techniques:

• Bleb-less surgeries gaining popularity
• Improved viscoelastic use and gonioscopic visualization
• Customized surgical approach based on glaucoma subtype

Laser-Assisted and Adjunctive Innovations

• Micropulse Transscleral Cyclophotocoagulation (MP-TSCPC): Safer cyclodestructive option
• Selective Laser Trabeculoplasty (SLT) as first-line or repeatable therapy
• Combination of MIGS with cataract surgery for synergistic IOP reduction

Future Directions

• Personalized glaucoma surgery
• Drug-eluting implants
• Sustained-release IOP-lowering devices
• AI-guided surgical planning
• Regenerative therapies targeting the trabecular meshwork

Conclusion

The landscape of glaucoma surgery has shifted from aggressive pressure-lowering procedures to tailored, patient-specific interventions. With the advent of MIGS and newer canal-based surgeries, ophthalmologists can now offer safer, effective, and earlier surgical options, improving patient quality of life while preserving vision.

Traditional surgeries continue to play a crucial role in advanced disease, but the future of glaucoma care lies in innovation, precision, and customization.