At the completion of this article, the reader should be able to improve their identification and referral of glaucoma patients, including:
- Understand the evolving landscape of glaucoma care and the shift towards interventional management.
- Learn to identify when shared care is necessary, particularly in patients with more advanced glaucoma and co-morbidities.
- Develop strategies to educate glaucoma patients on treatment options, emphasising early intervention and tailored approaches for long-term management.
Dr Kenneth Ooi
MBBS, Msurg (Ophth), FRANZCO
Clinical Senior Lecturer, Save Sight Institute, University of Sydney
Conjoint Lecturer, School of Medical Sciences, University of New South Wales
The growing number of ageing glaucoma patients presents both challenges and opportunities for eyecare professionals. DR KENNETH OOI explores how advancements in minimally invasive glaucoma surgeries and a deeper understanding of ocular surface disease are shaping personalised treatment strategies.
Over the past decade, myopia treatment has gradually evolved towards a more tailored approach. At the same time, there has been a growing consensus among eyecare professionals suggesting that it is now time for glaucoma care to follow a similar path. The reason for this is the increasing availability of minimally invasive glaucoma surgery (MIGS) devices, making interventional glaucoma management a more realistic option.
This progress enables eyecare providers to individualise diagnosis and monitoring based on each patient’s unique risk factors, while also creating treatment plans that align with the patient’s unique lifestyle and the severity of their condition.
Key considerations
One of the key considerations driving this evolution in glaucoma care is ocular surface disease (OSD) which as we know is a leading cause for referrals. Ocular surface disease prevalence in glaucoma can be up to 59%,1 and symptom manifestation has been documented in up to 74% of glaucoma sufferers.2 Glaucoma drops can contribute to OSD, but more importantly, it is the preservatives used with them that are causative.3
The presence of OSD not only reduces adherence to glaucoma drops and quality of life, but also increases glaucoma surgical failure, such as reduced trabeculectomy bleb survival from excessive inflammation.4-6
Another key consideration in this paradigm shift is cataracts, which often occur alongside glaucoma. Although the range of intraocular lens (IOL) options continues to grow as we work towards achieving aberration-free multifocality, the currently available multifocal IOLs are linked to increased dysphotopsia and reduced contrast sensitivity compared to monofocal IOLs. Since OSD is already associated with decreased contrast sensitivity, post-operative patients with OSD may experience an additional, compounded loss of contrast sensitivity.7
The most identifiable causes of multifocal IOL dissatisfaction are residual refractive error and OSD, with both as the most frequent concurrent complaints as highlighted in our review on cataract surgery and dry eye.7
SLT and iStents
Selective laser trabeculoplasty (SLT) is an established intraocular pressure (IOP)-lowering procedure performed with a doubled pulsed-frequency meodymium (Nd):YAG laser accessible to cataract/refractive surgeons. The laser selectively targets pigmented tissue of the trabecular meshwork (TM) to augment aqueous flow. iStent devices bypass the TM as a major aqueous outflow barrier, create a new drainage path, and allow fluid to flow more easily, reducing eye pressure.
During surgery, three heparin-coated, non-ferromagnetic titanium microstents can now be implanted in the form of iStent infinite (Figure 1). As with any form of surgery, MIGS devices and SLT have associated risks, but these have been found to be mostly transient and non-serious as highlighted in a systematic review by Cantor et al. (The most commonly reported complications were hyphema, peripheral anterior synechiae formation, mild inflammation and IOP elevation).8 More iStent-specific events include malposition and stent obstruction. Complications after SLT were reviewed as being generally rare with only use of rescue IOP-lowering medications and diurnal IOP fluctuations being noted.8
In the literature thus far, no significant difference in IOP-lowering at three years has been found between implantation of two iStents in the form of iStent inject W and SLT.9 The IOP-lowering effect of SLT has been shown to diminish over five years.10 There is a trend for iStent inject W lowering of IOP and glaucoma medications at least until the seven-year mark, whether combined with cataract surgery or as a standalone procedure.11
This trend for lowering of glaucoma medications has been replicated in a six-month local retrospective study of consecutive mild-to-moderate open-angle glaucoma private practice patients implanted with iStent inject W combined with cataract surgery and as a standalone procedure (Figures 2A-B). The percentages of eyes that were medication-free, ≥ one glaucoma medication reduction, and ≥ one mmHg IOP reduction in combined cataract surgery and iStent inject W patients (n=12) and standalone iStent inject W patients (n=11) were 50% and 36%, 75% and 73%, and 83% and 64%, respectively. Interestingly, the two exfoliative glaucoma eyes in the combination group also became medication-free despite the high pre-operative burden of four glaucoma drops. Only two cases of self-resolving small hyphema were observed in the standalone cohort.12
In terms of health economics, despite the higher initial cost of iStent implantation, it has been found that the annual costs after implantation were lower than those of both the medication-only group and the SLT group.13 A systematic review published in 2023 also showed greater reductions in medication use with iStents compared to SLT. The review concluded that, although further evidence is needed, existing economic studies suggest that MIGS devices, when combined with cataract surgery, are a cost-effective option for lowering IOP compared to cataract surgery alone.8
Additionally, studies have demonstrated significant improvements in OSD and quality of life following iStent implantation combined with cataract surgery, including reduced OSDI scores and medication use.14, 15 One prospective single-arm study by Schweitzer et al of patients with mild-to-moderate open-angle glaucoma on one to four glaucoma medications studied the effect of pressure-lowering on OSD of 47 eyes which underwent cataract surgery and iStent or iStent inject implantation. They showed that 73% of patients had moderate or severe OSDI scores pre-operatively but only 29% had such scores at three months post-operatively.
Furthermore, OSDI scores were recorded as normal in 57% at three months versus 9% pre-operatively. Significant improvements in TBUT, Oxford conjunctival/corneal staining and reductions in glaucoma medications were evidenced at three months.14
Similar significant improvements in OSDI, TBUT, surface staining and reductions in medications were also reported in a retrospective study of 57 patients who underwent iStent combined with cataract surgery at four months. This study, by Jones et al, also returned significantly improved glaucoma-
specific (GQL-15 and GSS) and general health (EQ-5D) patient-reported outcome measures of quality of life.15
iStent and cataract surgery
Samuelson et al. compared iStent inject implantation combined with cataract surgery to cataract surgery alone and found that the combination treatment resulted in greater improvements in patient-reported outcome measures at all follow-up visits over a 24-month period.16 The study, titled ‘Quality of Life in Primary Open-Angle Glaucoma and Cataract: An Analysis of VFQ-25 and OSDI From the iStent inject Pivotal Trial,’ shows that adding iStent to cataract surgery not only reduced eye pressure but also led to better patient-reported quality of life and a greater likelihood of being medication-free for a longer period.
Averages were 58.0% vs 45.8%; P < .05 for visual function questionnaire (VFQ)-25 composite scores and 56.7% vs 48.9%; P < .05 for OSDI composite scores. It found 75.8% of cataract surgery and iStent group versus 61.9% of the cataract surgery alone group experienced 20% or greater reduction from baseline in unmedicated IOP. In this 20% or greater group, 84% of treatment eyes versus 67% of control eyes were not receiving glaucoma medication at 23 months. Those who were VFQ-25 responders were also more likely to be medication-free at 24 months.15
Toward a tailored approach
As the range of treatment options for cataract and glaucoma care continues to expand, eye health care providers are presented with more opportunities to adopt a more tailored approach for cataract patients with mild to moderate glaucoma. As the concept of an ‘interventional approach to glaucoma’ gains more traction, glaucoma surgeons are, increasingly, advocating for early diagnosis and intervention treatments, including MIGs and SLT to preserve vision and quality of life. This approach enables more effective long-term management and highlights the need to explore alternatives to glaucoma drops that contribute to OSD.
Early identification of risk factors
Individualised diagnosis and monitoring, with an eye on the patient’s unique risk factors early on, for example, a tendency towards allergies or indeed pre-existing dry eye in those with rosacea blepharitis, can lead to better ocular surface preservation later when cataract surgery is required.
For pressure lowering of around 20-30%, in those who are appropriate candidates, SLT is a safe modality which can be successful 80% of the time. There are a variety of scenarios that I have encountered where patients have been unsuccessful with SLT or indeed unwilling to have SLT, thus making MIGS devices an appropriate alternative. These scenarios include patients who do not have enough brow clearance for the SLT gonio laser lens or who have too much in the way of iris processes insertion into the TM preventing laser access. Other settings include those with submaximal drops reduction and persisting OSD with debilitating dryness irritation, vision blur and unacceptable redness despite successful withdrawal of a glaucoma medication after SLT. There are also those also who are afraid of or reluctant to have laser treatment despite counselling and those who are unwilling to have multiple procedures in terms of cost and/or time when cataract surgery is more within sight and there is the realisation that a combined procedure can be conducted.
Shared care scenarios
Developing treatment plans early that suit the patient’s severity of disease as well as lifestyle and age will also enable more appropriate IOL selection as well as better aftercare for glaucoma patients post cataract surgery. It is therefore important that we are able to best educate our patients by informing them of all alternatives available for mild to moderate glaucoma in order to prevent disease progression and morbidity.
There is an increased range of extended depth of focus (EDOF) lenses being used by surgeons in well-controlled mild-to-moderate glaucoma cases with non-centre involving visual field defects. With refractive segmental as well as now non-diffractive extended wavefront EDOF IOLs having less loss of contrast sensitivity being available, surgeons are now more confident in their utilisation in glaucoma patients where OSD may be minimised with interventional glaucoma.
As multifocal IOLs are less likely to be implanted in patients with more glaucoma co-morbidities, the need for shared-care is paramount with tailored reading glasses as well as glaucoma monitoring still required.
Ultimately, our glaucoma patients deserve the best of the premium lens technologies available to us and with spectacle assistance still required by many post-operatively, care of OSD along with long-term vision and IOP stability can be had with timely interventional glaucoma management.
Acknowledgements: Dr. Kenneth Ooi would like to acknowledge the assistance of Jeff Megahan, commissioning editor, healthcare education in the writing of the article.
Disclosures: Dr Kenneth Ooi is a paid consultant of Glaukos Corporation.
More reading
Snow family donating $50m to glaucoma research at University of Sydney
Mental health plays role in glaucoma progression, researchers say
Glaukos iStent platform harnesses power of three-stent MIGS
References
1.Leung EW, Medeiros FA, Weinreb RN. Prevalence of ocular surface disease in glaucoma patients. J Glaucoma. 2008;17(5):350–5.59%
2. Mylla Boso AL, Gasperi E, Fernandes L, et al. Impact of ocular surface disease treatment in patients with glaucoma. Clin Ophthalmol. 2020; 14:103–11.
3. Tirpack AR, Vanner E, Parrish J, et al. Dry eye symptoms and ocular pain in veterans with glaucoma. J Clin Med. 2019; 8:1076.
4. Robin AL, Covert D. Does adjunctive glaucoma therapy affect adherence to the initial primary therapy? Ophthalmology. 2005; 112:863–8.
5. Skalicky SE, Goldberg I, McCluskey P. Ocular surface disease and quality of life in patients with glaucoma. Am J Ophthalmol. 2012;153(1–9): e2.
6. Broadway D, Hitchings R, Grierson I. Topical antiglaucomatous therapy: Adverse effects on the conjunctiva and implications for filtration surgery. J Glaucoma. 1995; 4:136.
7. Ooi KGJ, Leung KFC, Xiong J, Khoo P, Watson SL. Cataract Surgery and Dry Eye [Internet]. Cataract – An Update on Clinical and Surgical Management. IntechOpen; 2023. Available from: http://dx.doi.org/10.5772/ intechopen.1002481
8. Cantor L, Lindfield D, Ghinelli F, et al. Systematic Literature Review of Clinical, Economic, and Humanistic Outcomes Following Minimally Invasive Glaucoma Surgery or Selective Laser Trabeculoplasty for the Treatment of Open-Angle Glaucoma with or Without Cataract Extraction. Clin Ophthalmol. 2023 Jan 6; 17:85-101.
9. Pahlitzsch M, Davids AM, Winterhalter S, et al. Selective Laser Trabeculoplasty Versus MIGS: Forgotten Art or First-Step Procedure in Selected Patients with Open-Angle Glaucoma. Graefes Arch Clin Exp Ophthalmol. 2023 Apr;261(4):1063-1072.
10. Leahy KE, White AJ. Selective laser trabeculoplasty: current perspectives. Clin Ophthalmol. 2015; 9:833–41.
11. Hengerer FH, Auffarth GU, Conrad-Hengerer I. 7-Year Efficacy and Safety of iStent inject Trabecular Micro-Bypass in Combined and Standalone Usage. Adv Ther. 2024 Apr;41(4):1481-1495.
12. Ooi KG. A cataract and refractive surgeon’s early experience with iStent inject® W in Australian patients with open-angle glaucoma. Poster at APAO Bali, APACRS Chengdu, AUSCRS Hamilton Island and RANZCO Adelaide.
13. Berdahl JP, Khatana AK, Katz LJ, et al. Cost-comparison of two trabecular micro-bypass stents versus selective laser trabeculoplasty or medications only for intraocular pressure control for patients with open-angle glaucoma. J Med Econ. 2017;20(7):760–6.
14. Schweitzer JA, Hauser WH, Ibach M, et al. Prospective Interventional Cohort Study of Ocular Surface Disease Changes in Eyes After Trabecular Micro-Bypass Stent(s) Implantation (iStent or iStent inject) with Phacoemulsification. Ophthalmol Ther. 2020 Dec;9(4):941-953.
15. Jones L, Maes N, Qidwai U, et al. Impact of minimally invasive glaucoma surgery on the ocular surface and quality of life in patients with glaucoma. Ther Adv Ophthalmol. 2023 Feb 13
16. Samuelson TW, Singh IP, Williamson BK, et al. Quality of Life in Primary Open-Angle Glaucoma and Cataract: An Analysis of VFQ-25 and OSDI From the iStent inject® Pivotal Trial. Am J Ophthalmol. 2021 Sep; 229:220-229
