Surgically induced astigmatism and refractive outcomes after minimally invasive glaucoma surgery combined with cataract surgery

Minimally invasive glaucoma surgery (MIGS) is believed to induce less surgically induced astigmatism (SIA) due to smaller incisions, yet few studies have evaluated SIA in MIGS patients. This retrospective cohort study compared SIA and refractive outcomes among three MIGS techniques: first-generation trabecular micro-bypass stent (iStent [IS], n = 36), second-generation iStent inject W (IW, n = 39), and microhook ab interno trabeculotomy (μLOT, n = 36). SIA, refractive prediction error (RPE), intraocular pressure (IOP), and glaucoma subtype were analyzed. SIA remained minimal, with no significant differences between groups (p = 0.95, linear mixed model). RPE significantly differed between IW and μLOT (p = 0.025) but remained mild in both. The μLOT group exhibited a slight myopic shift and greater IOP reduction. However, absolute prediction error did not significantly differ among groups (p = 0.062). Subgroup analysis confirmed the refractive neutrality of MIGS across primary open-angle glaucoma, pseudoexfoliative glaucoma, and chronic angle-closure glaucoma. These findings support the refractive stability of MIGS when combined with cataract surgery, suggesting IS, IW, and μLOT as equally viable options from a refractive standpoint.