ARE YOU WELL-VERSED IN THESE MINIMALLY INVASIVE GLAUCOMA SURGERIES?

THE ADVANCEMENTS in minimally invasive glaucoma surgeries (MIGS) have allowed for the high safety and rapid recovery of our glaucoma patients.

TRAB AND SCHLEMM

Trabecular Meshwork/Schlemm’s Canal procedures target the trabecular meshwork, or conventional outflow pathway, to obtain access to Schlemm’s canal through a clear corneal incision. This access is obtained via trabecular bypass stents, excision of the trabecular meshwork, ablation of the trabecular meshwork or dilation of Schlemm’s canal. All procedures can be combined with cataract surgery.

Candidates: Mild to moderate glaucoma patients who desire a high caliber of safety and quick visual recovery vs. supraciliary procedures. Excision of the trabecular meshwork, ablation of the trabecular meshwork and dilation of Schlemm’s canal can be performed as standalone procedures.

Postoperative complications: Hyphema and corneal edema, mild, lasting usually one week. IOP spikes can occur through the first month postoperatively. The hypotony incidence is extremely low, as episcleral venous pressure of 8mmHg to 11mmHg keeps the IOP from dipping too low.

Co-management: Prescribe topical glaucoma medication to control the IOP spikes. Management often lasts about one month.

SUPRACILIARY PROCEDURES

These are comprised of stents, through a clear corneal incision, that access the supraciliary space, or unconventional outflow pathway, bypassing episcleral venous pressure resistance and obstructions within the trabecular meshwork. As a result, these procedures lower IOP and reduce topical glaucoma medication use.

Candidates: Patients who have visually significant cataracts and mild to moderate glaucoma.

Postoperative complications: Hypotony, one week hyphemas and IOP spikes. The risk of hypotony is higher than that from trabecular meshwork and Schlemm’s canal procedures, but lower than traditional filtration procedures, such as a trabeculectomy. Specifically, a study in Ophthalmology revealed a 2.9% rate of transient hypotony with a supraciliary device.

Co-management: Prescribe the addition of topical glaucoma medications to control the IOP spikes that can occur from these procedures. Management often lasts close to one month.

SUBCONJUNCTIVAL PROCEDURES

These procedures create a bleb in the subconjunctival space, bypassing episcleral venous pressure resistance and obstructions within the trabecular meshwork, providing the potential for low IOPs. In a U.S. pivotal clinical trial, a standalone placement of one subconjunctival device lowered IOP by 36.7% and reduced glaucoma medication use by 51.5%.

Candidates: Progressive moderate to severe glaucoma patients.

Postoperative complications: Hypotony and the possible need for bleb needling. In the clinical trial mentioned above, the former was seen in 24.6% of patients, and the latter was seen in 32.3% of patients.

Co-management: Monitoring the bleb and referring the patient back to the surgeon if bleb needling is needed. OM

DR. SCHWEITZER specializes in advanced glaucoma, refractive surgical clinical care and anterior segment pathology at Vance Thompson Vision. He has had multiple articles published and has delivered lectures on glaucoma, anterior segment pathology, refractive surgical clinical care and surgical management. Email him at justin.schweitzer@vancethompsonvision.com.