A Nuanced Approach to the Surgical Management of Glaucoma

The desire to create safer and more effective techniques to lower intraocular pressure (IOP) in patients suffering from glaucoma is as old as glaucoma surgery itself. Central to this goal is the need for tailored therapies that can address the individual patient's needs given that variability in anatomy and existing pathology can vary so widely in human conditions. For decades, trabeculectomy and subsequently, glaucoma drainage devices have been viewed as the gold standard for lowering IOP. While effective, and certainly beneficial for many patients, these techniques do not allow the surgeon to take a nuanced approach to the treatment of glaucoma. Minimally invasive glaucoma surgery (MIGS) is a relatively recent development that is geared toward achieving the promise of such a nuanced approach.¹,²

The common theme in all MIGS approaches is the targeted nature of the intervention along with a substantial decrease in tissue manipulation and collateral damage. One MIGS approach involves implantation of miniature devices to facilitate the natural flow of aqueous humor out of the anterior chamber and bypass the diseased trabecular meshwork. Yet, other implants are designed to shunt aqueous humor from the anterior chamber through nonphysiologic routes such as shunting large amounts of fluid through a ciliary cleft. Other approaches avoid the use of implants altogether and endeavor to remove diseased trabecular meshwork through cautery or delicate incision. Another MIGS category involves reduction of aqueous inflow through coagulation of the ciliary tissue with lasers or focused ultrasonic energy. Finally, newer techniques that aim to restore the natural function of the trabecular meshwork through mechanical oscillation and induction of extracellular matrix turnover have been introduced and are in the early stages of development. While all of these procedures are largely successful at increasing the safety profile of surgery, at this point they all produce a less robust reduction in IOP compared to traditional full-thickness filtration surgery.

MIGS devices and procedures are in their infancy. They allow surgeons to contemplate selecting the most appropriate treatment path for each given patient. While associated with a modest decrease in IOP at this time, these procedures still hold promise in permitting surgeons to utilize a thoughtful approach to the selection of which approach might be best. It is quite plausible to envision a shift in decision-making toward earlier surgical intervention for lowering IOP in patients with more mild to moderate glaucomatous optic neuropathy. In these cases, a more modest decrease in IOP might suffice and could lead to enhanced outcomes with better safety profiles. Thus, a nuanced approach is potentially the most appropriate and could lead to superior patient care. Only time will tell if MIGS as we define it today, will develop and maintain a strong and lasting position in the glaucoma treatment paradigm. However, it is clear that the narrative that has been introduced in our professional circles toward achieving tailored therapy and individualized care is in itself a victory for both the glaucoma surgeon and the patients we treat.