Background <p>Glaucoma surgery has payer-budget implications when postoperative medication and procedure use differ between care pathways. This study compared direct medical costs after gonioscopy-assisted transluminal trabeculotomy (GATT) and mitomycin-C-augmented trabeculectomy (MMC-trabeculectomy) from the Turkish Social Security Institution (SGK) payer perspective.</p> Methods <p>This single-centre retrospective cohort used patient-level chart, operating-room, and medication-cost data from sequentially reviewed surgery-naive adults with primary open-angle or pseudoexfoliation glaucoma who underwent GATT (<i>n</i> = 40) or MMC-trabeculectomy (<i>n</i> = 20). Surgical outcome was not an enrollment criterion. Costs were valued in 2025 Turkish Lira using SUT tariffs and the 11 June 2025 SGK drug price list. The primary base-case cost included the index glaucoma-surgery tariff, postoperative ophthalmology visits, dispensed glaucoma medications, and glaucoma-related non-routine postoperative procedures. Routine optical coherence tomography and visual-field testing were excluded from the primary surgical cost comparison and reported descriptively. Patient-level Gamma generalized linear models with log link estimated procedure-associated cost ratios.</p> Results <p>Mean observed postoperative follow-up was 11.45 ± 8.28 months after GATT (range 2–30) and 13.85 ± 6.91 months after MMC-trabeculectomy (range 3–25). Mean primary base-case direct medical cost was 3188.6 ± 1955.9 TRY after GATT and 6835.8 ± 4674.5 TRY after MMC-trabeculectomy. Medication cost was the largest incremental driver (924.0 vs. 3305.7 TRY per patient), accounting for 65.3% of the mean difference. Glaucoma-related non-routine procedure costs were 0.0 TRY per GATT patient and 271.1 TRY per MMC-trabeculectomy patient. In the fully adjusted Gamma model, MMC-trabeculectomy was associated with higher mean primary base-case cost (cost ratio 2.01; 95% CI, 1.50–2.70).</p> Conclusions <p>In this Turkish SGK payer-perspective analysis, MMC-trabeculectomy was associated with higher observed direct medical costs than GATT during available postoperative follow-up. The findings are limited by the retrospective single-centre design, imbalanced groups, nonrandomized surgical selection, no propensity-score matching or inverse-probability weighting, and short follow-up for long-term durability. They should not be interpreted as a long-term cost-utility analysis or causal evidence of economic superiority.</p> Trial registration <p>Not applicable.</p>