In this installment of Interventional Mindset, Christopher Spearman, MD, sits down with Douglas McGraw, DO, to review how ophthalmologists can implement standalone and combination microinvasive glaucoma surgery (MIGS) via the OMNI Surgical System (Sight Sciences).
Dr. Spearman is an ophthalmologist, managing partner, and principal investigator at Scott & Christie Eyecare Associates in Pittsburgh, PA, where he specializes in cataracts, glaucoma, macular degeneration, diabetic eye disease, and dry eye disease (DED).
Dr. McGraw is an anterior segment surgeon at Yuba Sutter Eye Care, Yuba City, CA, and specializes in cataracts, glaucoma, and ocular surface and lid surgeries.
Interventional Mindset is an educational series that gives eye physicians the needed knowledge, edge, and confidence in mastering new technology to grow their practices and provide the highest level of patient care. Our focus is to reduce frustrations associated with adopting new technology by building confidence in your skills to drive transformation.
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What is the OMNI Surgical System?
The OMNI Surgical System is an ab interno MIGS procedure that was cleared by the FDA in 2018. It is the first, and currently only, implant-free, single-use therapeutic glaucoma device for canaloplasty followed by trabeculotomy to reduce intraocular pressure (IOP) in adults with primary open-angle glaucoma (POAG).1
The device was designed to open and restore flow through the three points of known resistance within the conventional outflow pathway (i.e., the trabecular meshwork [TM], Schlemm’s canal, and collector channel) using a single, clear corneal microincision.1
Both Drs. McGraw and Spearman noted that after becoming familiar with the device and procedure, they transitioned to offering it as a standalone procedure to provide glaucoma patients with an alternative approach to lowering IOP and reducing medication burden outside of traditional glaucoma surgery.
As Dr. McGraw increasingly adopted MIGS procedures into his armamentarium, he identified more and more patients who would benefit from them, such as:
- Pseudophakic patients
- Those who struggled with adherence or toxicity to topical glaucoma medications
- Patients with moderate IOP control on multiple glaucoma drops that did not require a massive IOP reduction wherein he wanted to delay incisional glaucoma surgery
Studies on the safety and efficacy of the OMNI Surgical System
In 2022, the GEMINI study (NCT03861169) reported on the 12-month efficacy of 360° canaloplasty and 180° trabeculotomy using OMNI in combination with cataract surgery for mild to moderate open-angle glaucoma (OAG) and visually-significant cataract in 140 participants.2
GEMINI demonstrated that by month 12:2
- 84.2% of eyes achieved IOP reductions >20% from baseline
- The mean unmedicated diurnal IOP decreased from 23.8mmHg at baseline to 15.6mmHg at month 12
- 80% of eyes were medication-free
- The average number of glaucoma medications was 1.8 at baseline and was reduced to 0.4 at month 12
- 76% of eyes achieved IOP between 6 to 18mmHg
- Adverse events were uncommon
- Most were mild and self-limited and included transient hyphema (9 of 149, 6%) and transient IOP elevations (3 of 149, 2%)
Subsequently, a 36-month follow-up extension study (NCT05044793) enrolled 66 subjects, including those from GEMINI, with OAG or cataracts and researchers performed the same techniques as the original study on one eye of each patient using the OMNI.3
The extension study showed the long-term effects of OMNI, including:4
- 23.1mmHg baseline mean unmedicated IOP decreased to 16.7mmHg and 16.3mmHg at 24 and 36 months, respectively
- The proportion of eyes with ≥20% reduction in IOP was 77% and 78% at months 24 and 36, respectively, compared to 87% at month 12 in GEMINI
- 68% of patients at 24 months and 71% at 36 months had an IOP between 6 and 18mmHg
- 74% of patients (46 of 62) were medication-free at 36 months
- The mean number of IOP-lowering medications was 1.7 at baseline, which decreased to 0.4 at 24 months and 0.3 at 36 months
Comparing the efficacy of different MIGS procedures
This year, a large-scale, comparative, real-world clinical outcomes study was published in the American Journal of Ophthalmology International that analyzed the efficacy of the OMNI Surgical System, Hydrus Microstent (Alcon), and iStent inject (Glaukos Corporation) using data from the Intelligent Research in Sight (IRIS) Registry.5
In total, 77,391 OAG patients (109,745 eyes) were analyzed, organized into four cohorts, and divided into subgroups based on their pre-operative IOP (i.e., >18mmHg and ≤18mmHg):1,5
- OMNI cohort: 541 eyes
- High-baseline IOP: -6.64mmHg IOP reduction and -1.34 medication reduction
- Low-baseline IOP: -0.47mmHG IOP reduction and -1.42 medication reduction
- Hydrus Microstent cohort: 1,901 eyes
- High-baseline IOP: -5.57mmHg IOP reduction and -1.20 medication reduction
- Low-baseline IOP: +0.03mmHG IOP reduction and -1.18 medication reduction
- iStent inject cohort: 6,558 eyes
- High-baseline IOP: -4.96mmHg IOP reduction and -0.86 medication reduction
- Low-baseline IOP: -0.17mmHG IOP reduction and -0.95 medication reduction
- Cataract surgery cohort: 100,745 eyes
- High-baseline IOP: -5.55mmHg IOP reduction and -0.67 medication reduction
- Low-baseline IOP: -0.07mmHG IOP reduction and -0.65 medication reduction
As shown above, the study authors highlighted a sustained and significant IOP reduction across all four cohorts over the 24-month observational period, but the largest numerical reduction was in patients in the OMNI cohort.
Surgical pearls for the OMNI Surgical System
As the OMNI does not rely on an implant, both Drs. McGraw and Spearman noted that the soft catheter tip of the OMNI allows for flexibility in the angle to readjust and gain a different access point to the canal.
Dr. McGraw explained that for patients undergoing combined MIGS and phacoemulsification, he prefers to treat 180° for the canaloplasty part and elute the entirety of the viscoelastic, which in his surgical experience can get some patients to 360°. Then, he does 180° for the trabeculotomy part so there is room for him to go back in and retreat the patient if necessary. For standalone procedures, he treats 360° canaloplasty and 180° trabeculotomy.
Dr. Spearman added that he opts to treat 360° for the canaloplasty portion, and when he does the trabeculotomy portion he starts where the access point to the canal is—typically just straight across the eye in the nasal angle—and he tries to do just over a 90° trabeculotomy. He explained that the OMNI allows him to titrate the procedure depending on how much IOP-lowering is required for the patient; for example, he reserves the 360° trabeculotomy for patients with advanced glaucoma.
To hear more about how surgeons can customize the OMNI procedure for patients, watch the full interview!
Conclusion
Dr. Spearman noted that patients who were treated with the OMNI usually end up in the middle teens in terms of IOP and typically reduce their medication burden by at least one drop.
As such, both real-world data and clinical trials have demonstrated that the OMNI Surgical System significantly reduces IOP and the medication burden for glaucoma patients with a sustained treatment effect.
