Three-quarters of US glaucoma surgeons support interventional glaucoma. Numbers in the UK are similar. But what about the Australian context? Insight investigates.
“Glaucoma was initially a surgical disease, then the drops got better and the surgery dropped right off, and now the surgery is sort of coming back in different forms – so it’s a bit like the tide going in and out.”
The ebb and flow of that tide is constantly shifting the sand, and depending where a person stands, their stance can seem at times secure and at other times not.
Three ophthalmologists in the UK and Australia have taken different positions in the wave of change and evolution sweeping glaucoma care around the world and Down Under.
Time will tell which of them has found the most secure footing.
Professor Gus Gazzard is confident that he and his colleagues in the UK have located that prized piece of real estate.
Prof Gazzard is director of the glaucoma service at Moorfields Eye Hospital in the UK and, as one of the world’s most cited glaucoma researchers, was a drawcard speaker at the recent RANZCO Congress in Melbourne.
He’s well known as a key figure behind the landmark Laser in Glaucoma and Ocular Hypertension Trial (LiGHT), which made a strong case for the use of selective laser trabeculoplasty (SLT) as an alternative to eye drops in helping to control intraocular pressure (IOP) and manage glaucoma.
That 2019 study has helped fuel the global momentum for interventional glaucoma (IG), a change in attitude and action that encourages a move away from medical intervention and eye drops for managing glaucoma and towards earlier, more aggressive intervention, from SLT to surgical procedures, including minimally invasive glaucoma surgery (MIGS) techniques like insertion of stents to help lower IOP.
Other studies supporting interventional glaucoma include the EAGLE (Effectiveness in Angle-closure Glaucoma of Lens Extraction) trial confirming clear lens extraction in primary angle closure disease, and the TAGS (Treatment of Advanced Glaucoma Study) research revisiting primary trabeculectomy for advanced glaucoma.
Prof Gazzard, like the other surgeons interviewed by Insight, believes more work is required before widespread use of MIGS as a standalone intervention when considering the cost and risk of surgery.
But he believes that jury has already passed judgement on eye drops, in what he calls the biggest shift in glaucoma treatment in the past 50 years.
That shift has been bolstered by the latest LiGHT study data confirming the long-term value of SLT as an effective treatment.
Released late last year, it shows that SLT is more effective than eye drops in slowing visual field loss in patients with ocular hypertension (OHT) and open-angle glaucoma (OAG).
SLT, as part of an interventional glaucoma regime, will be the first line of treatment in the next five to 10 years, says Prof Gazzard.
It already is in the US, where a recent poll of specialists by the American Glaucoma Society revealed that 75% of them started treatment with SLT as part of interventional glaucoma, rather than eye drops or other medical treatments.
The numbers in the UK are similar, he says.
“Using primary SLT as the first treatment, that is very much the go-to, not just for me, but the vast majority in the UK now.”
“It’s actually mandated by the NHS (National Health Service), which guides us as to what we ought to be doing.
“You start with SLT and if it doesn’t work, you repeat it, because there’s good evidence now that a repeat SLT often does the job.”
Medication is only used to support those few patients who are unable to meet their IOP targets with SLT alone, and those whose other eye conditions make the procedure a greater risk.
Prof Gazzard says that reversal of clinical fortune is based on evidence showing that SLT is effective in managing IOP without the sometimes debilitating side effects of eye drops.
“There are a huge range of risks and side effects, complications from medications,” he says.
“With medication, patients come back complaining about the ongoing irritation, the stress, the fact they forget to use their drops.
“There’s a big impact on quality of life, from the fact that people are constantly reminded that they have the disease, constantly reminded that there’s something wrong with them, because every single day, or two or three times a day, they have to put in medication.
“With SLT they’re treated and their life doesn’t change, but you’ve taken away a series of anxieties or fears.”
He acknowledges SLT is not for everyone.
“There are a few specific exceptions where there are some people . . . who have a slightly greater risk from SLT – patients who’ve got uveitis, patients with previous vein occlusions or macular edema.”
However, for the “vast majority” of patients and professionals, “you’ve now got a situation where eye drops have probably been pretty superseded by all the other available opportunities, such as laser and MIGS.”
For surgeons who are yet to fully buy-in, it’s more about indifference rather than any concerns over a lack of evidence.
“I think there’s a lot of inertia,” says Prof Gazzard. “It’s easier to write a script than it is to reconfigure your service, to develop a laser service where patients need to come back for their treatment.
“You’ve got to make sure you’ve got a laser, you’ve got to have somebody to deliver the laser.
“Change takes time, and I think the slow uptake comes not from sceptics, but from apathy.”
Deliberation Down Under
While Prof Gazzard is confident that SLT is the right way to go and IG the secure land on which to build a successful and sustainable treatment platform, two specialists in Australia are watching closely.
Dr Colin Clement has witnessed the evolution and rise of SLT from a treatment used as an “add-on” to medical therapy for glaucoma management to one that is often used earlier and as the first line.
“It can be performed relatively quickly, has a good safety profile and quick recovery,” says the Sydney ophthalmologist, who lists cataract and glaucoma as sub-specialities and also undertakes clinical research and teaching.
Laser as a first-line treatment is an “excellent option”, and “there’s strong evidence to back that up now”, he says.
And earlier, interventional glaucoma makes a lot of sense “because any damage that occurs in glaucoma and any loss of vision that results from that is irreversible”.
Dr Clement uses plenty of SLT in his two clinics – in Sydney’s CBD and the south-western suburb of Fairfield.
He also uses plenty of eye drops, even though he acknowledges that for some patients with mild to moderate glaucoma, drops “can get to the point where the treatment is worse than the condition”.
But that treatment is not mandated by the guidelines laid down in a national health service; in Australia it’s the result of clinical decision-making and discussions with patients.
And even though that tide of change towards interventional glaucoma has made its way from the Northern Hemisphere, Dr Clement isn’t yet completely persuaded by the swell of evidence.
He offers SLT or medications to patients as first-line treatment, presenting both as equally good options with different pros and cons.
“I think the take-up would be about 50/50 (eye drops vs SLT),” he says.
“The way the doctor frames that information can have an influence on how that’s taken up, and I try to keep it as open as possible; having said that, if it was my eyes, I would opt for the laser.”
He prefers the flexibility of a mix of drops and SLT, depending on the patient in front of him and the severity of their IOP and glaucoma symptoms.
“The ones with the lower (IOP) pressures, you’d be more likely to go with the eye drops . . . and patients presenting with moderately high pressures are likely to do quite well with mixed procedures.”
He believes those patients with lower pressures and IOP targets are less likely to benefit from the addition of SLT.
But those with more severe IOP are likely to face the more powerful weaponry of interventional glaucoma, including invasive surgery such as a trabeculectomy.
Dr Clement accepts that the evidence backs SLT for pulling patients out of a potential life-long use of eye drops, and the side effects and ocular surface issues that can come with that.
But it’s not about a one-size-fits-all approach.
“Glaucoma is actually a complex condition, and it’s not one condition, it’s a bunch of different conditions, and every patient that sits in front of you is a bit different, so you need to tailor it to the patient,” he says.
“There are definitely patients in our clinic who have started on one drop, they have had an excellent response, they’ve had no side effects, and they’ve been doing it for years – that’s a brilliant outcome.”
Treatments can be imperfect
Although he sees the benefit of an IG approach, Dr David Wechsler believes it is part of a sometimes “confusing” ongoing evolution of treatments for the eye disease.
He’s a comprehensive ophthalmologist at Sydney’s Burwood Eye Clinic, who also works in public hospitals and is a board member at Glaucoma Australia (GA).
“I’ve been around long enough to see things come and go. We (GA) keep an open mind – at the end of the day, glaucoma is still not 100% understood”
“We can understand the potential benefits of SLT and earlier intervention in glaucoma, and are watching with interest the emerging evidence base.”
But “all treatments are imperfect, and all have got their risks and benefits”.
As predominantly a patient support and advocacy organisation, GA does not have an official stance on interventional glaucoma or offer guidelines on which treatment specialists should use.
“This is at the discretion of the individual clinicians, and it’s still a decision that you make with the patient,” says Dr Wechsler.
“What I personally do is I often start with drops but mention the laser.
“Patients are normally reviewed within a short timeframe after starting drop treatment, to see how they’re going with the drops. If it looks as though drops aren’t going to work, or they’re not tolerated, then maybe we think about laser earlier.”
Dr Wechsler believes that is common practice in Australia, and possibly in the US as well.
He’s curious about the figure that 75% of US glaucoma specialists started treatment with SLT.
“I was at the glaucoma subspecialty day of the American Society of Cataract and Refractive Surgery meeting last year.
“A speaker polled the audience ‘do you prefer to start newly diagnosed glaucoma patients on drops or laser?’ and about 70% of the audience’s hands went up for drops.”
But when the same group was asked what treatment they would prefer if they were the patient, about 70% opted for laser.
Dr Wechsler believes surgeons might be sold on SLT as a safe and effective form of interventional glaucoma, but it’s often the patients who are less convinced.
“When you offer it to the patient, there might be some hesitation about having the procedure.
“Some of my colleagues may say ‘Oh, we’re going to give you a light treatment’ rather than use the word laser to avoid putting patients off.
Some concern about SLT can be justified, says Dr Wechsler.
He has seen cases of cystoid macular edema, especially in patients who have had this before, and it is not appropriate for patients with various secondary glaucomas.
Albeit rare, complications and side effects are possible, he says.
“The LiGHT trial is one thing, but then, in the real world, extrapolating these findings to patients who might not fit the inclusion criteria for a clinical trial, or have other issues with their eyes, is another.
“I will mention SLT as an alternative, and that it can be used as a first-line treatment, but I tend to start patients on drops, and that is invariably their preference, at least initially.”
More needed on MIGS
If there is one thing that all three specialists agree on, it’s that there’s still a case to be made for widespread adoption of standalone MIGS.
At RANZCO 2025 in Melbourne, Prof Gazzard asked his audience to ponder whether interventional glaucoma and minimally invasive glaucoma surgery were “myth, magic or monster”.
He concluded that interventional glaucoma was not a myth – the evidence for non-pharmacological care is now substantial; it was not magic – advanced disease still demands “proper surgery for proper pressures”.
But he felt there was “some monster in the detail”, particularly around unacknowledged complications, confirmation bias, and the cost implications of a “MIGS-for-most” approach.
“Getting people away from medications is a good thing,” Prof Gazzard told the audience, “but we must be very careful that enthusiasm doesn’t outstrip evidence.”
A few months later that stance has not changed.
He believes the evidence from numerous studies shows MIGS have a role in helping people get off the eyedrops, reduce their dependence on sometimes harmful medication, and improve their quality of life.
In a pivotal trial of the iStent platform implanted at the time of cataract surgery, it was observed that 84% of patients were medication-free at 23 months. Plus, an independent study showed that after five years, on average, patients maintained a 40% reduction in IOP and a 71% reduction in medication burden. And a third study showed a 72% reduction of patients with severe ocular surface disease symptoms such as dry eye through three months post operatively.
But surgeons still have to consider whether the benefit is worth the risk of what is still surgery, with the complications and side effects that might follow.
They also need to consider if it’s value for money.
“Most people in the UK are not reaching for minimally invasive glaucoma surgery if they’ve got perfect vision and their pressure is not good enough; they’re reaching for minimally invasive glaucoma surgery if they are having cataract surgery anyway,” says Prof Gazzard.
That provides “a window” for the surgeon to include another procedure that will help end their dependence on drops.
Drs Clement and Wechsler agree with that approach.
MIGS is harder to justify as a standalone procedure, in their view right now.
“There’s an MBS code for a trabecular bypass procedure in conjunction with cataract surgery, and there’s a different code for the trabecular bypass procedure as a standalone,” says Dr Wechsler.
“This data would be available, and while I have not seen these numbers myself, I imagine it would be 10 to one, if not more than that (in favour of the dual surgery).
“I think a lot of us think about it at the time of cataract surgery. If we can improve the glaucoma control, if we can get them off glaucoma drops, or reduce the drops, that’s a good thing.”
Dr Clement says the cost-benefit analysis of MIGS is “something that is missing in all this discussion”.
“There’s been some analysis of iStent which shows that treatment with iStent is more cost effective than medication in the short to medium term.”
But specialists are keen to see more information on that.
“I think it has promise, and it’s an area in evolution,” says Dr Clement. “I think it should be adopted with caution. That’s how I would approach it.”
His Australian colleague too prefers a cautious approach and an open mind.
Until the ground underneath his feet becomes a little more certain.
