Phaco Plus MIGS

Ready

IAN CONNER, MD, PHD

Most glaucoma specialists likely see the value of performing phacoemulsification combined with MIGS (often referred to as phaco plus MIGS). Other eye care providers such as comprehensive ophthalmologists and optometrists, however, may have questions regarding the safety, efficacy, and utility of this approach. Considering several of these common inquiries helps to elucidate the advantages of phaco plus MIGS and confirm that this approach is ready for prime time.

What Is MIGS?

Treatment options for MIGS continue to expand, and it can be difficult to keep up with all the products and procedures available. Categories of MIGS include angle-based implants (eg, Hydrus Microstent [Alcon] and iStent [Glaukos]), nonimplants (eg, goniotomy and canaloplasty), cyclophotocoagulation, subconjunctival procedures (eg, Xen Gel Stent [AbbVie] and Preserflo Microshunt [Santen]), and suprachoroidal procedures (eg, AlloFlo [Iantrek] and Miniject [iStar Medical]). Many of these approaches are evolving as surgeons optimize their use.

Why Offer MIGS With Cataract Surgery?

When discussing phaco plus MIGS with other eye care providers, it is important to communicate at least three primary goals. This combined approach is used to (1) achieve better IOP control, (2) reduce the patient’s medication burden, and (3) alter the disease course. The first two objectives are easy to understand and evaluate, whereas the third—and ultimate—objective is harder to measure in a meaningful way.

Are Angle-Based MIGS Implants Safe?

Angle-based MIGS implants are safe. A review article of prospective randomized clinical trials and meta-analyses showed that trabecular meshwork (TM)–based and Schlemm canal–based MIGS procedures were associated with only transient adverse events.¹ A persistent loss of BCVA was reported to be around 1% to 2% or less in most studies reviewed.¹ Another review article concluded that a significant proportion of studies comparing phacoemulsification alone and phaco plus MIGS found no significant differences in the complication rates between groups.²

Are Angle-Based MIGS Implants Effective?

The COMPARE study demonstrated similar IOP outcomes for the Hydrus and iStent in patients with mild to moderate open-angle glaucoma (with a tendency for fewer postoperative medications required in Hydrus-treated eyes).³ In the HORIZON study, fewer secondary surgical interventions were required at 5 years in eyes treated with phaco plus Hydrus versus phacoemulsification alone.⁴ A post hoc analysis of the HORIZON data showed slower visual field progression and a smaller proportion of fast progressors in the group of patients treated with phaco plus Hydrus versus phacoemulsification alone.⁵

Are Angle-Based MIGS Implants Cost-Effective?

A cost-utility analysis showed that implantation of a Hydrus or iStent inject (Glaukos) at the time of cataract surgery was cost-effective when compared with phacoemulsification alone or medical management.⁶

What Are the Main Obstacles to the Adoption of Phaco Plus MIGS?

A major barrier to ophthalmologists’ adoption of phaco plus MIGS is discomfort with surgical gonioscopy. Ample educational resources are available (see video). Surgeons who are comfortable with this skill set should help teach their colleagues.

Some providers may be reluctant to adopt a phaco plus approach because they are concerned that the MIGS portion will add too much time to the cataract procedure. However, implantation of an angle-based MIGS device typically adds only 5 minutes or less to a case for surgeons with experience.

Concern about reimbursement for phaco plus MIGS also exists and is reasonable.

What Happens If MIGS Is Not Offered?

According to the Ophthalmic Mutual Insurance Company (OMIC), numerous claims related to cataract surgery involve patients who allege they were not informed of premium IOL options. OMIC therefore recommends that ophthalmologists inform patients of options for presbyopia correction and astigmatism reduction. Failing to discuss MIGS with patients undergoing cataract surgery may soon represent a similar breach of responsibility. The onus is on the eye care provider to inform patients of their options and to provide guidance on how to access technologies that the practice may not offer.

Which MIGS Procedure to Offer?

Many MIGS options are available. The quality of evidence is strongest for angle-based implants, but procedural selection should be based on several factors, including patient demographics, glaucoma type and severity, the need to reduce the medication load, cataract status, anticoagulant status, and more.

Summary

Offering or at least considering phaco plus MIGS is becoming the standard of care. As with premium IOLs, claims could arise if the option is not discussed with patients. Not every patient will be a suitable candidate for phaco plus MIGS, but certain benefits can be afforded to those who are.

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Or Not

ROMA PATEL, MD, MBA

Although combining phacoemulsification with MIGS offers benefits to many patients, a few points regarding its use are worth considering.

Positioning Challenges

Proper positioning of TM-based devices can be limited by several factors, even in the hands of experienced MIGS surgeons. Ophthalmologists may face difficulty visualizing and identifying anatomic structures, visualizing a stent once placed, and achieving a required view due to patient positioning. In a prospective analysis of the iStent inject, investigators found that 44.9% of the implants placed were not in the desired position.¹ Variations in position can also occur with the Hydrus Microstent, and it can be difficult to visualize the distal tip of the implant during device placement.²

Safety Concerns

Adverse events reported with TM-based implants include device obstruction, peripheral anterior synechiae formation, hyphema, and uveitis or iritis.³ In some cataract patients with only mild glaucoma, these risks may not outweigh the benefits of phaco plus MIGS. Even with a deviceless approach such as gonioscopy-assisted transluminal trabeculotomy, viscocanaloplasty, or goniotomy, serious complications such as cyclodialysis clefts and large hemorrhages can occur and complicate the postoperative course.

Procedural Uncertainties

TM-based procedures come with several uncertainties. Is the implant in the correct place? Is aqueous flow blocked by long-term scarring? Is there atrophy of the collector channels? Is there postoperative inflammation that could have been prevented? I personally would love to have aqueous angiography to identify where to target the TM and its downstream pathways. Also, we would all benefit from a method to predict which patients will experience fast disease progression or a verified technology to identify ganglion cell distress.

Available Alternatives

The most expensive minute in a hospital is a minute in the OR. It is worth considering whether the effect of a 5-minute MIGS procedure could be achieved with another more efficient procedure, such as traditional selective laser trabeculoplasty or direct selective laser trabeculoplasty (Voyager, Alcon). This laser treatment requires minimal time, is associated with few side effects, is repeatable, and preserves tissue.

Reimbursement Concerns

As more MIGS devices are adopted, the more often their associated CPT codes are used. These codes are then subject to reevaluation by Medicare. Unjustified utilization could ultimately lead to lower reimbursement.

Summary

Phaco plus MIGS is not a clear-cut approach for every surgeon and every patient. As with all treatment decisions, determining whether to perform MIGS in a cataract patient entails a risk-benefit analysis. It is ultimately the responsibility of glaucoma specialists to communicate the nuances of the disease and its surgical treatment to the broader ophthalmic community.