Glaucoma
Leading cause of blindness worldwide impacting 3 million people in America, and 76 million people globally, with diagnosis and treatment paramount in preventing vision loss.
Elevated eye pressure (IOP) is a significant risk factor for the progression of glaucoma. The primary goal of glaucoma treatment is to reduce eye pressure.
Traditional Treatments
Treatment options include topical glaucoma therapy, laser therapy, and incisional surgery. For many patients, topical glaucoma therapy can be associated with burdensome cost, challenges in adherence, side effects, drug allergies, and can also be limited in efficacy.
In the past, when glaucoma eye drops and laser treatment does not sufficiently lower the eye pressure, incisional surgery including trabeculectomy or glaucoma drainage device implantation is indicated.
While these therapies can be vision-saving, they require longer surgical time, can result in eye pressure fluctuations post operatively, can cause blurred vision, require frequent follow-up and prolonged recovery time, and can cause scarring that limits further incisional surgery.
Thus, these surgeries are often reserved for patients with more severe disease for whom more aggressive treatment is indicated.
Minimally Invasive Glaucoma Surgery (MIGS)
This historically has left a gap in ideal treatment available for patients with mild or moderate disease.
Since the early 2000s, the field of glaucoma has benefited from the emergence of micro or minimally invasive glaucoma surgery (MIGS), which has provided options to fulfill this unmet treatment gap.
Potential candidates for MIGs include patients with mild to moderate glaucoma, have topical glaucoma medication intolerance, have difficulty using their eye drops consistently, have allergies to these eye drops, or have persisting elevated eye pressure with progression of glaucoma.
MIGs may not always provide sufficient eye pressure reduction in more severe forms of glaucoma, for which traditional glaucoma surgery such as trabeculectomy or glaucoma drainage devices may be required. MIGS procedures have expanded since their advent in the early 2000s, but share five main features compared to trabeculectomy or glaucoma drainage device surgery:
1. Shorter surgical and recovery time: MIGS procedures typically are shorter procedures in the operating room, can easily be incorporated into cataract surgery, and typically have a shorter recovery time.
2. Minimal tissue disruption: MIGs involve less disruption to surrounding tissue than traditional glaucoma surgery.
3. Ab interno approach: while variations have evolved, typically MIGs can be performed through a traditional clear corneal incision with direct view of the surgical area.
4. Efficacy: MIGS often lower eye pressure less than traditional glaucoma surgery, but can offer approximately 20% eye pressure reduction in many cases and can still require topical therapy to maintain goal eye pressure.
5. Safety: MIGS typically are associated with less risk of serious complications including hypotony, choroidal effusion or choroidal hemorrhage.
Image edited from original: eyewiki.org/Microinvasive_Glaucoma_Surgery_(MIGS)
The Mechanics of These Glaucoma Surgeries Can Be Directed At:
Reducing aqueous production via ablation of the ciliary body.
Increasing outflow through:
- Bypassing the trabecular meshwork via the XEN tube, which connects the anterior chamber to the subconjunctival space.
- Enhancing outflow across the trabecular meshwork and through Schlemm's canal via an iStent or Hydrus.
- Enhancing outflow through excision of trabecular meshwork via Kahook goniotomy, Trabectome, Gonioscopy-assisted transluminal trabeculotomy (GATT), and OMNI.
- Enhancing flow via dilation of Schlemm canal through expansion with viscoelastic with VISCO360/OMNI, ABiC Ab Interno Canaloplasty, Streamline surgical system.
The emergence of MIGS has been a significant benefit to glaucoma patients, in offering broader treatment options for those with mild to moderate glaucoma, and can play a role in management of severe glaucoma.
For patients with difficulty obtaining, paying for or tolerating glaucoma medication, and lack of response to laser treatment, MIGs can be vision saving as an option to reduce eye pressure.
Thankfully, this evolution has broadened glaucoma treatment options and offers patients more tailored options to save vision.
Erika Wandel, M.D.
Glaucoma Fellowship: Mt. Sinai Hospital
(203) 596-1517 waterbury.refocuseyedoctors.com
87 Grandview Avenue Waterbury, CT
