Because cataract and glaucoma frequently coexist in the aging population, ophthalmologists often face the question of whether to address both conditions simultaneously. Combining cataract and glaucoma surgery can reduce the overall surgical burden, improve medication adherence, provide IOP control, and rehabilitate vision. The decision to combine procedures and the choice of which glaucoma surgery to perform, however, require a thoughtful, structured approach.
STAGING THE DISEASE
Decision-making in combined surgery is dictated by glaucoma severity. Mild disease is typically controlled with one or two IOP-lowering medications, and the patient exhibits minimal to no visual field (VF) loss or early nerve fiber layer changes. In this population, cataract surgery alone often modestly decreases the IOP, which may be sufficient. Increasing evidence, however, supports combining cataract removal with low-risk surgical options to address these individuals’ comorbid glaucoma.1-3 The increased risk of postoperative IOP elevation in glaucoma patients is well established. Compliance concerns and the side effects inherent to topical therapy make it easier to justify combining cataract and glaucoma surgery in patients with early disease—especially considering the favorable safety profile associated with some forms of intervention. Patients with moderate to advanced glaucoma may have even more to gain from a combined approach because surgical augmentation could achieve a more substantial or sustained IOP reduction.
When glaucoma surgery is warranted, the type of procedure should be tailored to the patient’s disease burden and goals of therapy. Mild to moderate glaucoma typically warrants MIGS. These procedures are well suited to those who need a modest reduction in IOP and/or medication burden. Ideal candidates have open angles, mild to moderate VF loss, an IOP target in the midteens or higher, and a desire to reduce or eliminate topical medications. In contrast, patients who have a history of synechial angle closure, advanced VF loss, or disease progression despite maximum tolerated medical therapy may benefit from more aggressive intervention.
Individuals with severe disease or a history of failed MIGS may require filtration surgery to achieve a low target IOP (< 12 mm Hg) or prevent disease progression. Combining phacoemulsification with trabeculectomy or tube shunt surgery introduces complexity and risk but is sometimes the only path to preserving vision. Filtration surgery generally offers the lowest IOPs, but the procedures are associated with a steeper learning curve and a higher risk profile compared with MIGS. Trabeculectomy is most appropriate for individuals without significant conjunctival scarring who can adhere to postoperative instructions. Tube shunts tend to be a better option for patients with extensive peripheral anterior synechiae, uveitis, neovascular glaucoma, or significant conjunctival scarring from previous surgery.
THE ROLES OF ANGLE ANATOMY AND
PRIOR TREATMENT
Gonioscopy remains critical to selecting the appropriate glaucoma procedure. Patients with open angles and minimal to no evidence of peripheral anterior synechiae are excellent candidates for MIGS. Patients with narrow angles, synechial closure, or neovascularization require alternative options. An adequate intraoperative view of the angle is required for MIGS, and corneal pathology or positioning challenges may limit the surgeon’s ability to complete the procedure safely.
Patients who have a history of failed laser trabeculoplasty (LTP) may be best served by canal-based MIGS or nontrabecular MIGS (eg, subconjunctival or suprachoroidal stents). LTP failure suggests that bypassing or excising the trabecular meshwork may not improve outflow sufficiently, as found in a small series of patients who underwent MIGS after recent selective laser trabeculoplasty (SLT).4 Another retrospective cohort study demonstrated that LTP might be associated with a higher risk of subsequent glaucoma surgery following MIGS, either performed with or without concurrent phacoemulsification.5 These studies highlight the need for more evidence-based guidance on which approach may be most beneficial to each individual, especially as the utilization of first-line SLT and earlier intervention continues to grow.
Patients who have a history of a failed bleb-forming procedure or conjunctival scarring may require a tube shunt. Although angle surgery after filtration surgery has been less favored historically, recent data have shown a potential benefit of bypassing and excising the trabecular meshwork after more aggressive intervention has failed.6,7
PATIENT FACTORS
Several key factors influence the selection of glaucoma procedure.
Patient Age
Younger individuals typically demonstrate more aggressive healing. The greater potential for multiple surgeries required over their lifespan is another factor. Preparing younger patients for the possibility of future intervention is vital; the discussion can help guide both how and when to intervene.
For older individuals, it may be reasonable to prioritize the safety and faster recovery associated with less-invasive intervention, especially if their life expectancy or systemic disease limits long-term follow-up. MIGS procedures may not achieve the target IOP, but they could slow disease progression or reduce the patient’s medication burden during the remainder of their lives.
Comorbidities
Patients with dementia or mobility issues may have trouble following complex postoperative drug regimens. Individuals requiring blood thinners may do better with a less tissue-disruptive approach (eg, trabecular bypass stent) than a goniotomy or suprachoroidal implant. Patients with systemic comorbidities contributing to their glaucoma (as often occurs with uveitic and neovascular glaucoma) may require more durable IOP control, justifying earlier filtration surgery.
Research has shown that a staged approach to filtration and cataract surgery typically yields better outcomes, but a recent review of the AAO’s Intelligent Research in Sight Registry found that standalone procedures were more likely to require reoperation than combined procedures. Standalone procedures nonetheless achieved a greater reduction in IOP by percentage change from baseline.8 Other considerations that may influence the decision to combine or stage cataract and filtration surgery include patient access, transportation, and systemic health factors that may make separate surgeries more challenging.
Recovery Expectations
Some patients prioritize fast visual recovery and minimal downtime—factors favoring cataract surgery alone or combined with MIGS. Other patients are highly motivated to reduce their medication burden or preserve their vision at all costs, which may warrant a more involved combined approach. Those whose vision has been minimally affected by glaucoma tend to have similar expectations regarding their postoperative vision as individuals who do not have the disease. Combining cataract surgery with MIGS provides an opportunity to reduce the burden of medication, which can in turn improve ocular surface health and overall quality of vision. It is also reasonable to use less invasive procedural options such as SLT or sustained drug delivery to minimize the impact of topical therapy on preoperative measurements.
CONCLUSION
When deployed judiciously, combined cataract and glaucoma surgery is a powerful tool. MIGS can offer excellent results to patients with mild to moderate glaucoma, but filtration procedures remain essential for the management of advanced disease. The decision to combine procedures and the choice of glaucoma surgery are grounded in a careful assessment of disease severity, angle status, surgical history, and patient-specific health and lifestyle factors. Ultimately, the surgeon’s responsibility is to balance efficacy, safety, long-term IOP control, and the practical realities of the patient’s life. A structured, individualized approach can optimize surgical outcomes while preserving the patient’s vision and quality of life.
1. Samuelson TW, et al; iStent inject Study Group. Prospective, randomized, controlled pivotal trial of an ab interno implanted trabecular micro-bypass in primary open-angle glaucoma and cataract: two-year results. Ophthalmology. 2019;126(6):811-821.
2. Ahmed IIK, et al; HORIZON Investigators. Long-term outcomes from the HORIZON randomized trial for a Schlemm’s canal microstent in combination cataract and glaucoma surgery. Ophthalmology. 2022;129(7):742-751.
3. Ventura-Abreu N, García-Feijoo J, Pazos M, Biarnés M, Morales-Fernández L, Martínez-de-la-Casa JM. Twelve-month results of ab interno trabeculectomy with Kahook Dual Blade: an interventional, randomized, controlled clinical study. Graefes Arch Clin Exp Ophthalmol. 2021;259(9):2771-2781.
4. Teplitsky D, Wallace-Carrete C, Falah H, Trzcinski J, El Helwe H, Solá-Del Valle D. Does SLT response predict MIGS response? Invest Ophthalmol Vis Sci. 2024;65(7):1919.
5. Mitchell W, Yang SA, Ondeck C, et al. Effectiveness of angle-based minimally invasive glaucoma surgery after laser trabeculoplasty: an analysis of the IRIS Registry (Intelligent Research in Sight). Ophthalmol Glaucoma. 2024;7(4):335-344.
6. Lin F, Nie X, Shi J, et al. Safety and efficacy of goniotomy following failed surgery for glaucoma. J Glaucoma. 2023;32(11):942-947.
7. Sarkisian SR Jr, Grover DS, Gallardo MJ, et al; iStent infinite Study Group. Effectiveness and safety of iStent Infinite trabecular micro-bypass for uncontrolled glaucoma. J Glaucoma. 2023;32(1):9-18.
8. Ciociola EC, Yang SA, Hall N, et al; IRIS Registry Data Analytic Center Consortium. Effectiveness of trabeculectomy and tube shunt with versus without concurrent phacoemulsification: Intelligent Research in Sight Registry longitudinal analysis. Ophthalmol Glaucoma. 2023;6(1):42-53.
