The number of people with glaucoma in the United States is estimated to reach 4 million by the year 2040 and 6 million by the year 2060.1 Timely diagnosis and continual management of patients are imperative to prevent blindness from this silent thief.

Due to the sheer number of patients who have or will develop glaucoma in the United States, I believe that optometry and ophthalmology must collaborate on the care of these patients. When the typical first-line options of topical glaucoma medications and selective laser trabeculoplasty have been exhausted, surgical intervention usually becomes necessary. At Vance Thompson Vision, we feel that successful collaborative care can be a win-win-win situation for the optometrist, the ophthalmologist, and, most importantly, the patient. Therefore, we apply this model to our delivery of MIGS care, as described below.

THE KEY TO SUCCESSFUL COLLABORATIVE CARE

The key to any successful collaborative care relationship is communication.

In our practice, the optometrist communicates to the ophthalmologist the treatment options that have been used to manage the patient being referred for surgical consultation, communicates any conditions that could affect the ophthalmologist's decision on which surgical procedure is used, and communicates what education has been provided to the patient on their surgical options. In return, the ophthalmologist communicates to the optometrist the surgical option that was selected and why it was chosen and returns the patient to the optometrist in a timely fashion for continued long-term glaucoma management.

In order for this relationship to be successful, we feel it is important for the optometrist to understand the types of MIGS procedures available and which procedures are commonly used for which types of patients. It is also imperative for the optometrist to understand and be prepared to help manage postoperative complications that may arise from MIGS procedures.

POSTOPERATIVE PEARLS

In collaborative care for a glaucoma patient undergoing a MIGS procedure, we have found that it is most efficient for the optometrist to educate the patient preoperatively on expectations, for the ophthalmologist to perform the surgery, and for the optometrist to handle certain elements of postoperative care while working closely with the ophthalmologist.

The preoperative educational component should include explaining to the patient that a MIGS procedure will not cure the disease and that periodic follow-up with the optometrist will continue postoperatively. Discussion should also address potential postoperative complications.

The postoperative role of optometrists in our practice then includes recognizing and managing those complications if they occur. Five postoperative considerations are addressed here.

No. 1: Determining When to Stop Topical Glaucoma Medications

Patients who undergo MIGS procedures that target the trabecular meshwork or Schlemm canal often have mild to moderate glaucoma. IOP in these patients has generally been controlled with one or two topical glaucoma medications. Setting an individualized target IOP for each patient is helpful in determining when to stop glaucoma medications postoperatively.

If target IOP is obtained at 1 week postoperatively, it is fine to stop glaucoma medications and monitor the patient over the next few months. I will usually stop only one glaucoma medication at a time. If there is concern about a steroid response, waiting until 1 month postoperatively to stop topical glaucoma medications, once the steroid has been discontinued, is reasonable as well.

Patients who undergo a subconjunctival stent procedure should have topical glaucoma medications stopped at the time of surgery or at the 1-day postoperative visit, because these patients have a higher risk of experiencing hypotony.

No: 2: Managing IOP Spikes

IOP spikes are a common and obvious postoperative consideration in the management of a patient after a MIGS procedure. The decision of how aggressive to be with lowering IOP is based on the severity of the glaucoma. In the event of a severe IOP spike, adding an oral glaucoma medication to the patient’s topical glaucoma medications can help reduce the IOP. Oral agents are a temporary fix, but they can be effective for short periods of time.

In an emergent situation in which elevated IOP could quickly compromise the health of the optic nerve head, anterior chamber decompression is an effective way to reduce IOP rapidly. The patient should be placed on a topical glaucoma medication and observed closely over the next couple of days to make sure that the IOP spike does not recur.

No. 3: Managing Hyphema

Any MIGS procedure can create a mild, transient hyphema.2-4 During the preoperative examination, it is important to educate the patient that there is a possibility of cloudy vision for about 1 week after surgery due to hyphema. On slit-lamp examination, the appearance of the hyphema will be similar to an anterior chamber reaction. This situation is not urgent, and the patient may be monitored until it resolves. If a large hyphema is present, the patient should be referred back to the ophthalmologist for an anterior chamber washout.

No. 4: Managing Hypotony

MIGS procedures that target the trabecular meshwork and Schlemm canal are not associated with a risk of hypotony. This is because episcleral venous pressure (approximately 7–12 mm Hg) is not bypassed by these procedures, so IOP should not become low enough to create hypotony.

This is not the case with subconjunctival stent procedures, which bypass episcleral venous pressure. Hypotony may occur after these MIGS procedures,5 in which case the first step in management is to discontinue topical glaucoma medications. The next steps are to watch for the formation of the anterior chamber, make sure there is no iridocorneal touch, and to perform a fundus examination to rule out choroidal effusions.

No. 5: Performing Gonioscopy

Postoperative visualization of the MIGS procedure with a goniolens is helpful to identify failure of the procedure or stent obstruction leading to an increase in IOP. I recommend performing gonioscopy once in the first 3 months after the procedure and once per year after that.

EMBRACE THE RELATIONSHIP

Although perhaps unique, the collaborative care model described herein has proven successful in our delivery of MIGS care. Embracing a collaborative care relationship allows clinicians to achieve timely diagnoses and management for their patients with glaucoma. The key component of these relationships is communication. It is a win for all involved when communication is carried out efficiently and transparently.

1. National Eye Institute. Glaucoma Data and Statistics. Accessed May 17, 2021. www.nei.nih.gov/learn-about-eye-health/resources-for-health-educators/eye-health-data-and-statistics/glaucoma-data-and-statistics

2. 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(1);29-37.

3. Samuelson TW, Sarkisian SR, Lubeck DM, et al; iStent inject Study Group. Prospective, randomized, controlled pivotal trial of an ab interno implanted trabecular micro-bypass in primary open-angle glaucoma and cataract. Ophthalmology. 2019;126(6);811-821.

4. Sarkisian SR, Mathews B, Ding K, Patel A, Nicek Z. 360º ab-interno trabeculotomy in refractory primary open-angle glaucoma. Clin Ophthalmol. 2019;13:161-168.

5. Allergan. Directions for Use for the Xen Glaucoma Treatment System. Accessed September 6, 2019. https://allergan-web-cdn-prod.azureedge.net/actavis/actavis/media/allergan-pdf-documents/labeling/xen/dfu_xen_glaucoma_treatment_system_us_feb2017.pdf