According to data from the CMS and MarketScope, 15% to 20% of the 4 million cataract surgeries in the United States occur in patients who have comorbid glaucoma or ocular hypertension. About one quarter of those patients undergo a micro-invasive glaucoma surgery (MIGS) procedure at the same time,¹ yet evidence suggests that many more patients may benefit from a combined MIGS/cataract procedure.

Here, I discuss the benefits of MIGS stents at the time of cataract surgery in greater detail, and the role optometrists play in their use.

MIGS BENEFITS

MIGS stenting procedures, performed in conjunction with cataract surgery, have shown to lower IOP and reduce the medication burden on the patient. For example, in FDA clinical trials for both the iStent inject trabecular micro-bypass stent (Glaukos, now also available as the 3^rd-generation iStent inject W) and the Hydrus Schlemm’s canal MicroStent (Alcon), a little more than three-quarters of patients had a ≥20% reduction in unmedicated IOP at 2 years, as well as highly statistically significant (p < 0.001) reductions in mean IOP.^2,3 Additionally, high percentages of eyes implanted with these devices were completely medication free for years after surgery.^4,5 Additional studies have found similar links between trabecular micro-bypass stents in cataract surgery and decreased IOP and medication use.^6-11 For example, patients who underwent cataract surgery with iStent inject implantation still had a mean IOP of 13.6 mmHg at 5 years, a 40% reduction from preop, and were able to sustain a 71% reduction in the number of topical medications.¹⁰

Reducing the medication burden can also have a positive impact on the ocular surface. The rate of ocular surface disease among glaucoma patients is high, and rises with the number of topical medications.¹² Within just 3 months of surgery, patients implanted with 1 or 2 trabecular micro-bypass stents, for example, saw significant improvements in staining, TBUT and OSDI scores.¹³ Further, an exploratory analysis suggests that reducing medication dependence and implanting a trabecular micro-bypass stent in cataract surgery patients can improve quality of life, compared to cataract surgery alone.¹⁴

The safety profile of MIGS procedures with the stent devices indicated for mild to moderate glaucoma at the time of cataract surgery is similar to that of cataract surgery alone.^2,3 In the worst-case scenario, the procedure won’t be as effective as hoped and the patient may still need drops. Additionally, if the patient’s glaucoma continues to progress over time, as it certainly will in some patients, trabecular micro-bypass MIGS procedures preserve the conjunctiva for future filtering surgery.

Capitalizing on a one-time opportunity to implant tiny stents at the time of cataract surgery is one of the best ways I know to set the patient up to avoid or delay trabeculectomy — and all the risks that go with it. Managing a patient who has undergone a trabeculectomy involves a lifetime of worry, not just about the ptosis that may result from the procedure, but also about possible bleb failure and infection, bleb leaks, and possible hypotony.

OD’S ROLE

There are several steps ODs can take when it comes to MIGS:

1. Identify surgeons in your area who employ MIGS. Finding those surgeons who have embraced MIGS puts us in a better position to make appropriate referrals when our glaucoma patients need cataract surgery. Be sure to ask what their stance is on MIGS at the time of cataract surgery for mild, moderate, and severe glaucoma, as well as those on medication for ocular hypertension.
2. Provide patient education. In addition to discussing MIGS personally, I like to give patients some literature to take with them to their referral appointment. Written information helps with recall and empowers the patient to raise the topic with the surgeon.
3. Document. It is important to document, in both the patient’s chart and surgical referral notes, the patient’s glaucoma history and the fact that they may benefit from MIGS. That makes your intentions clear to the surgeon.
4. Follow-up. MIGS doesn’t cure glaucoma. Optometrists will still need to see the patient at the same follow-up frequency to monitor for progression of glaucoma, and will still need to perform regular OCT, VF and gonioscopy testing. These visits and tests are generally reimbursable. (See “Postoperative Management of MIGS,” below.)
5. Cease the drop that has the greatest side effects. After the eye has completely healed from the surgery and is back to its normal state, about 60 to 90 days postop, I typically stop the drop that has the greatest side effects and evaluate what effect that has on IOP.

In my experience, responsibly reducing the number of drops patients need is an excellent way to grow a practice, because it has such a positive impact on word-of-mouth referrals. I have found that the financial return on one happy patient who tells their friends and family that they are off drops far exceeds that of any marketing campaign I could run.

Postoperative Management of MIGS

Expect to see the patient at Day 1, Week 1, and Month 1, as the follow-up care is most often the same as traditional cataract surgery. 

Examine the angle and the stent using gonioscopy at the Week 1 visit. If iris tissue is obstructing the stent, refer the patient back to the surgeon.

 

 

Mild, transient microhyphemas are common but are rarely noticed by the patient; refer the patient back to the surgeon if there is a significant amount of blood or recurring hyphema.

 

 

Check IOP and treat pressure spikes accordingly (often retained viscoelastic or a steroid responder).

 

 

Wait 60 to 90 days, once the eye is completely healed and all postoperative anti-inflammatory medications have been discontinued, before attempting to reduce the number of IOP-lowering drops.

 

EXPLORE MIGS

As an optometrist, my priority is to do my patients no harm. When it comes to glaucoma in a cataract patient, I think the harm lies in not exploring MIGS and empowering patients to take advantage of this once-in-a-lifetime opportunity. OM

REFERENCES

1. Lindstrom RL. More comprehensive ophthalmologists should offer MIGS with cataract surgery. Ocular Surgery News, September, 2020. Accessed at: https://www.healio.com/news/ophthalmology/20200831/more-comprehensive-ophthalmologists-should-offer-migs-with-cataract-surgery .
2. Samuelson TW, Sarkisian Jr. SR, Lubeck DM, et al. Prospective, randomized, controlled pivotal trial of an ab interno implanted trabecular micro-bypass in primary open-angle glaucoma and cataract: Two-year results. Ophthalmology 2019;126:811-21.
3. Samuelson TW, Chang DF, Marquis R, et al; HORIZON Investigators. A Schlemm canal microstent for intraocular pressure reduction in primary open-angle glaucoma and cataract: The HORIZON Study. Ophthalmology. 2019;126:29-37.
4. Hengerer FH. Personal experience with second-generation trabecular micro-bypass stents in combination with cataract surgery in patients with glaucoma: 3-year follow-up. ASCRS 2018 Presentation.
5. Ahmed IK. 5-year follow up from the HORIZON Trial. American Glaucoma Society Virtual Annual Meeting, March 2021.
6. Arriola-Villalobos P, Martinez-de-la-Casa JM, Diaz-Valle D, et al. Glaukos iStent inject trabecular micro-bypass implantation associated with cataract surgery in patients with coexisting cataract and open-angle glaucoma or ocular hypertension: a long-term study. J Ophthalmol. 2016;2016:1056573.
7. Guedes RAP, Gravina DM, Lake JC, Guedes VMP, Chaoubah A. Intermediate results of iStent or iStent inject implantation combined with cataract surgery in a real-world setting: a longitudinal retrospective study. Ophthalmol Ther. March 2019;8:87-100.
8. Clement CI, Howes F, Ioannidis AS, Shiu M, Manning D. One-year outcomes following implantation of second-generation trabecular micro-bypass stents in conjunction with cataract surgery for various types of glaucoma or ocular hypertension: multicenter, multi-surgeon study. Clin Ophthalmol. 2019:13;491-499.
9. Manning D. Real-world case series of iStent or iStent inject trabecular micro-bypass stents combined with cataract surgery. Ophthalmol Ther. 2019;8:549-561.
10. Hengerer F. Auffarth G, Conrad-Hengerer I. Five-year outcomes of trabecular micro-bypass stents (iStent inject) implanted with or without cataract surgery. World Glaucoma Congress 2021.
11. Ahmed IK, Rhee DJ, Jones J, et al. Three-Year Findings of the HORIZON Trial: A Schlemm Canal Microstent for Pressure Reduction in Primary Open-Angle Glaucoma and Cataract. Ophthalmol. 2021;128:857-865.
12. Rossi GCM, Pasinetti GM, Scudeller L, et al. Risk factors to develop ocular surface disease in treated glaucoma or ocular hypertension patients. Eur J Ophthalmol. 2013;23:296-302.
13. Schweitzer JA, Hauser WH, Ibach M, et al. Prospective interventional cohort study of ocular surface disease changes in eyes after trabecular micro-bypass stent(s) implantation (iStent or iStent inject) with phacoemulsification. Ophthalmol Ther 2020;9:941-953.
14. Samuelson TW, Singh IP, Williamson BK, et al. Quality of life in primary open-angle glaucoma and cataract: An analysis of VFQ-25 and OSDI from the iStent inject pivotal trial. Am J Ophthalmol. 2021;229:220-229.

DR. SMOLENYAK practices at Albemarle Eye Center, a US EYE practice, in Edenton, N.C., where he specializes in perioperative management and the medical management of ocular surface disease, macular degeneration, glaucoma, and other conditions. He is a speaker for Glaukos. Contact him at ssmolenyak@aecpec.com.