Navigating the Maze

Determining the right combination in cataract and glaucoma surgery. Dermot McGrath reports.

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Determining the right combination in cataract and glaucoma surgery. Dermot McGrath reports. Surgical strategies for treating concomitant cataract and glaucoma have evolved considerably over the past decade. Substantial evidence has accumulated in support of the use of cataract surgery as a primary treatment modality for both acute angle-closure glaucoma and chronic angle-closure glaucoma. The widespread adoption of minimally invasive glaucoma surgery (MIGS) has transformed the management of open-angle glaucoma, with surgeons now intervening earlier and more frequently compared to traditional filtering surgery. Yet while techniques and technology have advanced, a consensus on the optimal approach to tackle the increasing number of patients with coexisting cataract and glaucoma remains elusive. Surgeons face a daunting variety of factors before deciding which approach - standalone, combined, or sequential surgeries - is best suited to a particular patient, depending on age, severity of glaucoma, cataract grade, lifestyle, profession, and other criteria. COMBINED SURGERY ADVANTAGES “Combined surgery has many potential advantages, and cataract surgery is a window of opportunity, but from the perspective of the payers and health service, we must prove the value for the patient of the different techniques and justify the indications,” said Julián García-Feijoo MD, Professor and Chairman of Ophthalmology at Hospital Clínico San Carlos, Madrid, Spain. From Dr García-Feijoo’s perspective, combined surgery is an excellent and justified option in patients with ocular surface disease, adherence problems, and ocular or systemic side effects from glaucoma medications. “The same is true for early glaucoma and ocular hypertension (OHT) patients with high IOP on maximum medical therapy. But more evidence is needed to indicate the surgery to improve quality of life related to glaucoma medication use, at least in the public health system,” he told EuroTimes. Choosing the best strategy is not always easy, but certain basic principles can help point surgeons in the right direction, believes Roberto Bellucci MD, Head of the Ophthalmic Unit at the University Hospital Verona, Italy. “I have a very clear opinion on patients with cataract and open-angle glaucoma. If there is some optic nerve damage, both diseases should be treated at the time of cataract surgery. In these cases, I prefer filtration surgery, either by adding a trabeculectomy to the cataract procedure or implanting a filtering device like the XEN® Gel Stent (Allergan Inc.) or the Preserflo™ MicroShunt (Santen). On the other hand, when there is no optic nerve damage, and the IOP is elevated but controlled by topical betablockers, I do the cataract first and leave the glaucoma balance for later stages,” he said. Not all cases are so clear-cut, and many eyes fall in between these two conditions, Dr Bellucci added. “They may have ocular hypertension well or poorly controlled by two or more topical drugs but no optic nerve damage. These eyes are the ideal candidates for non-filtering MIGS, and implants like the Hydrus® Microstent (Ivantis) or the iStent inject® (Glaukos) are my preferred choice for these patients.” REDUCING THE THRESHOLD FOR CATARACT SURGERY Although there is now robust evidence from the EAGLE triali and other studies of the pressure-lowering benefit of cataract extraction (and even clear lens exchange in angleclosure glaucoma), the situation is more nuanced and complex when it comes to primary open-angle glaucoma, said Professor Gus Gazzard, Director of the Glaucoma Service at Moorfields Eye Hospital and UCL Professor of Ophthalmology, London, United Kingdom. “We know cataract surgery alone will reduce IOP quite well. In the HORIZON study of patients with mild to moderate glaucoma, the control arm was 48% drop free at the end of two years after cataract extraction without a MIGS procedure. Other randomised studiesii have also shown the control arm of cataract extraction alone gives significant pressure reduction, so clearly lens extraction can help,” he said. Prof Gazzard said the weight of evidence reduced the threshold at which he now considers performing cataract surgery. “I have now got an extra reason for doing cataract surgery, supported by good evidence that it lowers pressure out to five years in the HORIZON trial. And depending on the specific situation, the addition of a MIGS procedure may reduce the threshold for cataract surgery still further,” he said. WHICH SURGERY FOR WHICH PATIENT? Dr García-Feijoo echoed the view that the threshold for cataract surgery, with or without MIGS, has been lowered in glaucoma patients in recent years. “Ocular hypertensive and early glaucoma patients can certainly benefit from combined phaco-MIGS surgery. We are essentially offering medication-free time and probably a better quality of life. And in general, postoperative complications and recovery time are very similar to phacoemulsification alone,” he said. Although standalone phacoemulsification is probably a better first surgical option for the majority of primary angleclosure glaucoma cases, combined phacoMIGS surgery may be viable in mild openangle glaucoma, Dr García-Feijoo said. In cases with uncontrolled moderate to advanced glaucoma or primary open-angle glaucoma with very high IOP, he usually opts for sequential surgery. “The key question is what surgery comes first, and there is no easy answer—it depends on glaucoma stage and progression rate, IOP, age, visual acuity, and related quality of life issues,” he said. PATIENT ROLE Dr Bellucci said it was important to distinguish between filtering and non-filtering MIGS as the demands of each surgery are significantly different from a patient perspective. “I think non-filtering MIGS can be implemented in every patient, since the postoperative protocol does not require anything special as compared with cataract surgery. Filtering MIGS is different. Patients should fully understand the need to apply the proper therapy at the right time by coming for control visits as scheduled by the surgeon and ultimately by understanding we need them to play an active role in their postoperative glaucoma care,” he said. The significance of chair time and patient compliance should not be underestimated, Dr García-Feijoo agreed. “It is important to talk to the patient and address aspects such as barriers to medication use, side effects of medications, fears or bad medical or surgical experiences, specific surgical complications, and consequences of the different treatment options. If the patient is informed and takes responsibility for their care planning and treatment, then the decisions we take will be better—and probably the long-term outcome too,” he said. WHICH MIGS FOR WHICH PATIENT? For Prof Gazzard, any patient scheduled for cataract surgery taking medications for glaucoma should automatically be considered for a MIGS procedure—preferably one with some clinical trial evidence behind it. “I would strongly advocate choosing a MIGS device based on the available evidence and assessing the risk according to the individual patient and the surgeon’s technique. There is now a very good review of MIGS procedures summarising the evidence from randomised controlled trials (RCTs).iii We see that apart from Hydrus Microstent and iStent, there is currently very little evidence for any of the other MIGS devices. So we definitely need more RCTs of these devices going forward,” he said. In planning the surgery, the risk-benefit profile of each MIGS technique will inevitably influence the risk profile for that particular patient, Prof Gazzard added. “For example, haemorrhage is not usually of concern with Hydrus or iStent but is a worry for a Gonioscopy-Assisted Transluminal Trabeculotomy (GATT) procedure. Likewise, prolonged inflammation is not usually a worry for the implantable devices but is a concern for endoscopic cyclophotocoagulation. So we need to bear in mind that one technique may be riskier for one individual than another,” he said. PATIENT-CENTRED CARE As surgeons gain experience with MIGS and pharmacologic and surgical therapies continue to evolve, glaucoma surgeons will increasingly be able to offer individualised treatment strategies. However, despite the advantages, MIGs will probably not be effective for the entire lifespan of younger patients, Dr Bellucci cautioned. “Glaucoma care is changing from a single, more dramatic surgery to minimal and safer procedures that may be repeated over time and titrated according to actual patient needs. This prospect should also be explained to our glaucoma patients,” he said. Dr García-Feijoo agreed the new glaucoma surgeries, often combined with phacoemulsification, are durably changing the treatment algorithm, with shorter recovery time and less impact on quality of life compared to conventional filtering surgeries. “All this could help us indicate glaucoma surgery earlier, but we should not forget the increased costs and the fact more evidence for many of these new surgeries is still needed. Newer could be cooler, but it is not always better. Filtering procedures such as trabeculectomy or deep sclerectomy are excellent glaucoma surgeries routinely used for combined procedures with excellent results,” he said. Prof Gazzard also insisted on the importance of glaucoma care as ultimately guided by the evidence of benefits that actually matter to the patient. “In the Laser in Glaucoma and Ocular Hypertension (LiGHT) trial, we were able to demonstrate that laser trabeculoplasty gave better visual field protection than eyedrops, even when treated to the same pressure. The HORIZON trial also demonstrated that the Hydrus was able to reduce medication burden and protect against the need for additional glaucoma surgery over five years. These are the type of outcomes that really matter to patients, and our management strategies need to be guided by the available evidence,” he concluded. i Azuara-Blanco, Augusto, et al. “Effectiveness of Early Lens Extraction for the Treatment of Primary Angle-Closure Glaucoma (Eagle): A Randomised Controlled Trial.” The Lancet, 2016 Oct; 388(10052): 1389–1397, https://doi.org/10.1016/s0140-6736(16)30956-4. ii Craven ER, et al, Journal of Cataract & Refractive Surgery. 2012 Aug; 38(8): 1339–45; Samuelson TW, et al, Ophthalmology. 2011 Mar; 118(3): 459–67. iii Bicket, A. K., et al, JAMA Ophthalmology. https://doi.org/10.1001/jamaophthalmol.2021.2351 Professor Gus Gazzard MA(Cantab), MD, MBBChir, FRCOphth: g.gazzard@nhs.net Professor Roberto Bellucci MD: roberto.bellucci52@gmail.com Professor Julián García-Feijoo MD: jgarciafeijoo@hotmail.com