A new report published in Ophthalmology by the American Academy of Ophthalmology’s (AAO’s) Ophthalmic Technology Assessment Committee Glaucoma Panel examined the efficacy of combined cataract surgery and minimally-invasive glaucoma surgery (MIGS) vs. cataract surgery alone for open-angle glaucoma (OAG) treatment and management.
Let’s start with some background.
The AAO panel sought to test the clinical and surgical hypothesis that doubling up on pressure-lowering procedures may produce meaningful results over time for OAG patients.
And the goal?
Researchers evaluated three key items:
- Reduction of IOP from combo of trabecular (aka MIGS) with cataract surgery
- Safety data for these procedures
- Highlight patient characteristics that may favor one procedure over another
So how’d they do this?
Investigators conducted a peer-reviewed literature search of the PubMed database (for English-speaking articles only) in February 2021 (initially) that was later updated in April 2023.
How many articles were identified?
A total of 279 were selected, which was then narrowed down to 20 articles that adhered to the researchers’ inclusion and exclusion criteria.
Of the 20 articles—assessed for quality by the AAO panel’s methodologist—10 of the randomized controlled trials (RCTs) were rated at Level 1.
To note, a Level 1 rating refers to evidence from a systematic review (such as this literature search) of all relevant RCTs.
Additionally, only the 10 Level 1-rated RCTs—all of which were subject to potential industry-sponsorship bias—were included in the final assessment.
What did they focus on in these RCTs?
Two major areas:
- Amount of IOP reduction (for those RCTs that performed a medication washout)
- IOP reduction with concurrent medication (for RCTs with no medication washout)
Now the findings…
For those RCTs at the 2-year mark with a medication washout, an IOP reduction of 5.4 to 7.6 mmHg IOP reduction was observed following cataract surgery alone.
Further, adding a MIGS procedure on top of cataract surgery for patients with hypertensive, mild to moderate OAG demonstrated an additional IOP reduction of 1.6 to 2.3 mmHg.
And in terms of treatment compliance?
The data suggested the potential to eliminate 1.2 to 1.4 medications when the patient undergoes a combined MIGS and cataract surgical approach.
Meaning?
Per the researchers: “adding a trabecular procedure provided an additional 3.8% to 8.9% IOP reduction over cataract surgery alone, which itself provided 21% to 28% IOP reduction.”
Did the types of trabecular procedures performed make a difference?
Nope. Based on the data, the researchers reported no clear benefit was observed in selecting one procedure over another.
However, they noted that the top three procedures in these studies—iStent/iStent Inject (Glaukos); Hydrus Microstent (Alcon), and excisional goniotomy (Kahook Dual Blade; New World Medical)—”appear to produce similar results among hypertensive, mild to moderate OAG subjects with modest IOP reduction or medication reduction over cataract surgery alone at two years,” they wrote.
What about patient considerations?
The authors noted that patient-specific considerations like uveitis predisposition, a bleeding risk, metal allergy, or narrowing of Schlemm’s canal could serve as guidance when selecting which MIGS technique to use in combination with cataract surgery.
Limitations?
They acknowledged that out of the 10 Level 1 RCTs examined, no data contained efficacy of trabecular procedures in patients with a pretreatment IOP of 21 mmHg or less.
And recommendations for future research?
The authors advised that future research should be based on three items:
- Standardizing outcome definitions
- Avoiding industry sponsorship bias
- Studying the efficacy of the trabecular procedures in normotensive OAG