Just Asking

With Ike Ahmed, Earl Randy Craven, Marlene Moster, Constance Okeke, I. Paul Singh, and Robert N. Weinreb

For Ike Ahmed, the Advanced Glaucoma Technologies (AGT) Forum has a clear goal: “To discuss perspectives and practice in the rapidly changing field of glaucoma management – to talk about what’s real and what isn’t, and what’s relevant for today’s practice.” And Forum participants were keen to drive that discussion with pointed questions:

How should we respond to the CyPass situation?

Robert N. Weinreb cautions against over-reaction: “If we applied similar standards to the Baerveldt and the Ahmed glaucoma products, they too would have been recalled, thereby depriving many patients of excellent outcomes.”

Ahmed adds that there is limited evidence for significant CyPass-associated damage: “The five-year COMPASS study did not find any patients with progressive permanent corneal edema or clinically evident corneal swelling.” He suggests that more detailed investigations are required, noting that cell loss tends to be associated with deeply positioned, rather than anteriorly located, devices. “Assessment based on the number of rings is probably less useful than measuring how far the implant extends into the cornea.”

“Nobody in the COMPASS study was shown to lose any corneal vision,” says Paul Singh. “The important point is the risk-to-benefit ratio – in patients who need lower IOP, I’m willing to risk endothelial cell loss to preserve optic nerve function.” And that risk-benefit ratio is also likely to apply, in some form, to non-CyPass devices; as Constance Okeke says, “If we dug deeper we’d probably find endothelial cell loss in other procedures – but we’d still do them routinely, just as we do tube shunts despite their known risks.”

Randy Craven’s approach is to contact each CyPass recipient using attorney-approved wording, check the device position and take a baseline endothelial cell count. “Subsequent decisions are made on a case-by-case basis,” says Craven. “But over-prominent devices should be addressed.” Ahmed notes, however, that CyPass removal can be challenging: “It is strongly secured to the angle – therefore we recommend a trimming technique.”

Finally, Weinreb reminds us that it’s in the nature of exciting new technologies to have risks; we should expect to be learning things about them after their introduction into clinical practice, he says, and Ahmed notes that updated data and guidance are available online (1, 2). In summary, Weinreb concludes, “The CyPass affair suggests the need for more research and more data – it does not mean we should throw the baby out with bathwater with regard to other MIGS procedures.”

Will the Innfocus make trabeculectomy redundant?

Marlene Moster answers carefully, noting the advantages of the MicroShunt device: “It gives a good, diffuse bleb that is more predictable than the trabeculectomy bleb, and patients’ vision returns sooner than with standard trabeculectomy.” For those reasons, she believes Innfocus will become a standard component of the toolkit for lowering IOP.

Can drug delivery devices assist glaucoma management?

Recent developments in the field of sustained drug delivery include intracameral biodegradable and non biodegrable products, and intracanalicular biodegradable inserts for ocular surface drug delivery. Singh has been involved in trials of sustained release prostaglandins and of the Glaukos sustained drug delivery device. His view? “These products have excellent efficacy and will no doubt help to answer the compliance issue.”

Craven too has experience of sustained release prostaglandin studies. “Surprisingly, a single injection can keep IOP in the middle or low teens for two years in 25 percent of patients,” says Craven. “And that’s why these products are likely to have some role in glaucoma management.”

There will be a logistical learning curve, says Singh, to fit these drug delivery devices into our workflow and reimbursement structures: “How often will they need to be administered, and who will pay?” Craven does not anticipate frequently repeated administrations: “We’ll probably initially use this approach in selected patients who might particularly benefit.” Singh concludes that drug delivery devices may be used as part of a hybrid approach, or as a pre-MIGs strategy to address compliance issues, but as time goes on, may see these delivery devices being used even earlier in the disease.

How will artificial intelligence change our approach to glaucoma?

Weinreb is unambiguous: “It will change everything – in fact, some predict that in 50 years it will have eliminated the need for surgeons.” His own view is that clinical risk modeling – for example, to determine those at greatest risk of glaucoma progression or blindness, and hence to guide management – will rely on deep-learning algorithms. He concludes that AI will bring great change, not only in healthcare but throughout society. Indeed, AI is already upon us – the first approval of an AI test (for diabetic retinopathy) occurred very recently. Weinreb adds, “Several other AI products are being developed for diagnosing and monitoring glaucoma.”

Craven, however, identifies issues that must be addressed before AI can have its full impact: “Glaucoma is a long-term disease – we’ll need a way of accessing and integrating all the various imaging and field data people accrue as they relocate over time.” Nevertheless, Craven also points out that there is already commercial interest in this field, and asserts his belief that solutions to the data access and integration issue will be found.

Should we anticipate any other significant technology advances?

Technology continually moves ahead, in all fields, but Singh is particularly excited by methods of labeling apoptotic cells in vivo. “If we can detect compromised cells before significant cell loss, we can treat patients much earlier – and maybe also identify those who we are unnecessarily treating,” says.

Conclusions?

Ahmed wraps up: “This is a golden age for glaucoma; technology is enabling us to be more interactive and interventional, without forgetting that clinical decisions must be informed by quality of life considerations.” In brief, these are exciting times – but, as always, the patient perspective remains of fundamental importance.

The Advanced Glaucoma Technologies Forum was hosted by The Ophthalmologist and supported by Ellex, Santen, Heidelberg Engineering, Reichert Ametek and Aerie Pharmaceuticals Inc.

Ike Ahmed is Assistant Professor at the University of Toronto, Canada.
Earl Randy Craven is Associate Professor of Ophthalmology at Johns Hopkins University, Maryland, USA.
Marlene Moster is Professor of Ophthalmology, Wills Eye Hospital, Philadelphia, USA.
Constance Okeke is a glaucoma and cataract surgery specialist at Virginia Eye Consultants, and also an Assistant Professor of Ophthalmology at Eastern Virginia Medical School, Virginia, USA.
I. Paul Singh is an ophthalmic surgeon at Eye Centers of Racine and Kenosha, Wisconsin, USA.
Robert N. Weinreb is Distinguished Professor and Chair, Ophthalmology, and Director, Hamilton Glaucoma Center, University of California, San Diego, USA.