For decades, the treatment pathway for glaucoma followed a predictable sequence: medicated eye drops first, laser treatment if drops were insufficient, and traditional filtration surgery — trabeculectomy — as a last resort. Trabeculectomy is effective, but it is also invasive, carries meaningful risks, and requires a long recovery. Many patients and their doctors delayed surgery for as long as possible, accepting the burden of multiple daily drops and the side effects that came with them.

That landscape has changed. A new category of procedures, collectively known as MIGS — minimally invasive glaucoma surgery — has opened a middle ground that did not previously exist. Smaller, safer, and faster to recover from, MIGS is reshaping how glaucoma is managed in South Africa and around the world.

Understanding the Problem MIGS Solves

In most forms of glaucoma, the fundamental problem is drainage. The eye produces a clear fluid called aqueous humour that circulates inside the front of the eye and exits through a drainage structure called the trabecular meshwork. When this drainage becomes inefficient, fluid builds up, intraocular pressure (IOP) rises, and the optic nerve is progressively damaged.

Every glaucoma treatment — drops, laser, or surgery — works by either reducing the amount of fluid the eye produces or improving the rate at which it drains. MIGS focuses on the drainage side, using tiny devices and microsurgical techniques to restore or enhance the eye’s natural outflow pathways.

What Makes MIGS Different

MIGS procedures share several characteristics that distinguish them from traditional glaucoma surgery:

• Performed through tiny incisions inside the eye, using an “ab interno” approach — from the inside out — avoiding external incisions, sutures, or external drainage blebs.
• Recovery measured in days rather than weeks.
• A complication profile significantly lower than trabeculectomy.
• Many procedures can be performed at the same time as cataract surgery — both addressed in a single operation under one anaesthetic.

The Main MIGS Procedures

iStent

The iStent is the smallest medical device ever implanted in the human body. Made of titanium, it is placed into the trabecular meshwork to create a permanent bypass channel for fluid drainage. It is most commonly implanted during cataract surgery and is designed for patients with mild to moderate open-angle glaucoma. The procedure adds only a few minutes to the cataract operation and requires no additional recovery.

Hydrus Microstent

The Hydrus is a crescent-shaped scaffold, approximately 8 millimetres long, that is placed inside Schlemm’s canal — the main collector channel for aqueous fluid. It dilates and scaffolds the canal over three clock hours, dramatically improving outflow. Like the iStent, it is typically implanted during cataract surgery.

GATT (Goniotomy-Assisted Transluminal Trabeculotomy)

GATT is a technique that opens the full 360 degrees of the trabecular meshwork from inside the eye using a microcatheter. It is a more aggressive approach than stent-based MIGS and is suitable for patients with moderate to advanced glaucoma who need a greater pressure reduction.

XEN Gel Stent

The XEN is a soft, gelatin-based tube implanted through the eye wall to create a new drainage pathway into the subconjunctival space — similar in concept to a trabeculectomy but with a much smaller, less invasive footprint. It is suited to patients with more advanced disease.

Who Is a Candidate for MIGS?

MIGS is not a replacement for all glaucoma surgery. It works best in early to moderate open-angle glaucoma, particularly in patients who:

• Are already having cataract surgery.
• Are struggling with the side effects or inconvenience of daily eye drops.
• Have pressure that is not adequately controlled by drops alone, but does not require the maximal reduction that trabeculectomy provides.
• Want to reduce their dependence on daily glaucoma medications.

For patients with advanced glaucoma or very high pressures, traditional surgery may still be the most appropriate option. The decision between MIGS and other approaches is always individualised, based on the type and stage of glaucoma, the target pressure, and the patient’s overall eye health.

The Advantage of Combining MIGS with Cataract Surgery

One of the most compelling aspects of MIGS is that it can be performed during cataract surgery without meaningfully increasing surgical time, risk, or recovery. For patients who have both cataracts and glaucoma — which is extremely common in patients over 60 — a combined procedure addresses two problems in one session. This means one anaesthetic, one recovery period, one set of post-operative visits, and often a meaningful reduction in the number of daily eye drops the patient needs going forward.

What to Expect After MIGS

Recovery from MIGS is typically straightforward. Most patients experience minimal discomfort and can return to normal activities within a few days. Vision may fluctuate slightly during the first week as the eye heals and pressure stabilises. Post-operative drops are prescribed for several weeks. The ophthalmologist will monitor intraocular pressure closely in the weeks and months following the procedure to assess the response and adjust any remaining medications accordingly.

It is important to understand that MIGS does not cure glaucoma. Glaucoma is a chronic, lifelong condition. MIGS is a tool for better controlling it — lowering pressure, reducing medication burden, and slowing disease progression. Ongoing monitoring remains essential.

MIGS in Durban

If you have been diagnosed with glaucoma and are managing it with drops, or if you are scheduled for cataract surgery and also have glaucoma, a conversation about whether MIGS may be appropriate for you is well worth having.