Debate sessions have been a popular format thus far at APGC 2024. At a Day Two symposium, some of the biggest names in glaucoma jousted on some of the spiciest topics in glaucoma management.
The time-honored tradition of debate as a tool to push human understanding is alive and well at the 7th Congress of the Asia-Pacific Glaucoma Society (APGC 2024) in Manila. The APGC 2024 scientific program designers have sprinkled them liberally throughout the Congress program, including a Day Two rumble on hot topics in glaucoma management.
Add into the mix a lineup of some of the great glaucoma gladiators from Asia-Pacific and the world, and this becomes a rumble for the ages. And that is precisely what transpired on a stormy afternoon in the Philippine capital, with names like Profs. Clement Tham (Hong Kong), Leonard Yip (Singapore) and Anton Hommer (Australia) taking the stage to joust over topics like selective laser trabeculoplasty (SLT), optical coherence tomography-retinal nerve fiber layer (OCT-RNFL) and trabeculectomy.
Round 1: SLT vs. medications in primary open angle glaucoma
The opening debate featured about as classic as 1975’s Thrilla in Manila between boxers Joe Frazier and Muhammad Ali: first-line treatment of primary open angle glaucoma (POAG) with drops vs. SLT.
In the opening round, Prof. Hommer took the side of medications, and specifically drops—all while navigating the seemingly innumerable permutations at the intersection of patient and disease.
“When we choose a new medication, what do we have to consider in our choice? We have to look at the stage and type of glaucoma, the topical and general conditions, and of course we need to speak with the patient,” he said. “We always have to consider the pros and cons.”
After walking through the various types of glaucoma and the pros and cons of various medications, it was in the consideration of disease stage that Prof. Hommer took his first swipe at SLT.
“If you have an advanced stage of glaucoma and a long life expectancy, you need a significant IOP lowering effect,” Dr. Hommer said. “There are medications that lower the initial pressure up to 30 mmHg or more. This is, in my opinion, much stronger than SLT, which usually has a success rate lowering intraocular pressure of 20% from the start.”
SLT, he further asserted, does not make sense to perform more than twice due to diminishing returns and safety concerns. “Medications, however, you can combine and switch, and there are a lot of possibilities,” he said.
Interestingly, Prof. Hommer also turned medication’s traditional weak point—compliance—into a strength. “If a patient complains about side effects, you know that this patient is taking the drugs—so you can control compliance. But if you perform SLT, the patient thinks he is cured.”
This hot take was countered by Prof. Andrew White (AUS) almost immediately in his defense of SLT. “It doesn’t matter what class of mediation that you use, people aren’t taking them 9-12 months down the track,” he said, referencing an Australian study from 2021 on patient drop compliance.1
The rest of Prof. White’s counterpunches stemmed from the LiGHT trial, which he believes has gone a long way towards filling a gap in long-term SLT data with its 36-month and 72-month follow-ups.
Prof. White reported that 76.6% of the 36/12 mmHg target IOP group in the 36-month trial required only one SLT treatment, and 78.2% of the group reached the target IOP without drops. And in the 72-month follow-up, 69.8% remained at or less than the target IOP without medical or surgical treatment.
More eyes in the drops arm of the 72-month trial results (26.8% vs. 19.6%; p=0.006) also exhibited progression, and this drove home Prof. White’s final point. “Chasing a number is not necessarily what we’re after. It’s chasing progression. And in SLT, on the basis of this trial…there was considerably less progression in SLT,” he said.
“And so that really, for me, for a treatment naive patient who is amenable to SLT as a first-line treatment, the complete decrease in progression and less reliance on adherence really puts a very strong case for why SLT should be done as a first-line treatment.”
Round 2: To escalate or not to escalate based on RNFL-OCT
OCT mania is in full force in ophthalmology, and glaucoma is no exception. But can ophthalmologists go too far? This was the question for the next round of debate, when Drs. Syril Dorairaj (USA) and Vijaya Lingnam (India) traded verbal arguments on whether retinal nerve fiber layer-OCT (RNFL-OCT) could be relied on alone to make decisions about escalating treatment.
Dr. Dorairaj struck first with his arguments in favor of relying on RNFL-OCT alone to take a patient’s treatment to the next level. On his opening point on the causative relationship between structural and functional damage, however, there was little disagreement between the two sides.
“It’s always the structural damage that precedes functional damage—that’s a given,” Dorairaj said. “It’s not a matter of which one came first, the chicken or the egg.” Dr. Lingnam agreed, but a closer look at the nature of this relationship may make RNFL-OCT less relevant than this implies. She argued that threshold values drop more slowly in early disease and faster with advanced disease.
This means that RNFL-OCT might have a usefulness limited to the early stages only. “If you look at the relationship, in the early part of the disease, visual field changes will not be seen, and you will potentially see structural changes with OCT as well. But once the disease becomes moderate to severe, it’s more of the visual field changes than the structural changes.”
This is a part of the well-established floor effect of OCT in glaucoma—and therefore dilutes the predictive power of this imaging modality demonstrated by Dr. Doraija, according to Dr. Lingnam. This power is further diminished by the variability in OCT scans themselves, including artifacting, and segmentation error.
At the end of this friendly debate, Dr. Lingnam stated her conclusions. Though RNFL-OCT is a powerful tool and perhaps can be used in isolation to make decisions earlier on in the disease, there’s more to the picture.
“Both structure and function are important, but management should be based on both. What’s important if you want to escalate treatment is to reconfirm the progression and that what we are seeing is real progression, with no artifacts involved,” she said.
FINAL ROUND: Needling vs. medications in troubled trabs
Everyone knows that trabeculectomies may not always go as planned, and what to do with inadequate post-trabeculectomy IOP lowering was the topic of the final talk on this stormy Manila afternoon.
Prof. Yip began by making the case for needling. His presentation began by arguing that trabs often fail due to scarring, and that bleb needling is a direct way to break or stop this scarring.
“You can lift the scleral flap up again, you can recannulate the sclerostomy, and with adjunctive medications like 5-FU or mitomycin C, you can stop the recurrence of scarring. Bleb needling thus directly deals with the cause of inadequate IOP reduction after trabeculectomy,” said Prof. Yip.
Prof. Yip then argued that medication reduction is always the goal in glaucoma, and that anything that can be done to avoid eye drops or reduce medication burden is worth doing. Besides, he remarked, glaucoma medications can damage the eye, with some actually increasing fibrosis.
In defense of drops, however, Dr. Frances Meier-Gibbons (Switzerland) argued that modern drops can lower IOP without significant side effects—and even positive ones, including the antifibrotic action observed in Rho kinase (ROCK) inhibitors and alpha-2 agonists. This makes such drugs and others good choices in the case of partial bleb scarring, according to Dr. Meier-Gibbons.
Both doctors agreed, however, that drops must still be used with care. Even Dr. Meier-Gibbons acknowledged the issues with drops, from the adherence to ocular surface issues. She did note that newer approaches to drops, from preservative-free formulations to ROCK inhibitors and once-a-day latanoprostene-bunod are changing things, and that the IOP reduction with drops is still the gold standard when you absolutely must bring pressure down.
For Prof. Yip, this gives a clear advantage to needling, which he described as effective and repeatable if necessary. “Needling works well to reduce intraocular pressure, the medication burden and the future procedure burden,” he said.
“Patients we know are living longer and longer than glaucoma,” he said, echoing one of the most salient themes in all of the enlightening debates on glaucoma treatment on display during the symposium. “So don’t give up on your trabeculectomies so easily. Needle them!”
Editor’s Note: Reporting for this event took place during the 7th Congress of the Asia-Pacific Glaucoma Society (APGC 2024), held from May 24-26, 2024 in Manila, Philippines.
References
- Daniels B, Healey P, Bruno C, Kaan I, Zoega H. Medicine treatment of glaucoma in Australia 2012-2019: prevalence, incidence and persistence. BMJ Open Ophthalmol. 2021;6(1):e000921.
- Gazzard G, Konstantakopoulou E, Garway-Heath D, et al; LiGHT Trial Study Group. Laser in Glaucoma and Ocular Hypertension (LiGHT) Trial: Six-Year Results of Primary Selective Laser Trabeculoplasty versus Eye Drops for the Treatment of Glaucoma and Ocular Hypertension. Ophthalmology. 2023;130(2):139-151.
