Selective Laser Trabeculoplasty versus Latanoprost: A Randomized OCT Angiography Study of Retinal Microvascular Changes in Glaucoma and Ocular Hypertension

PRCIS: SLT and latanoprost achieved significant IOP reduction, while macular and peripapillary OCT-A-derived vascular parameters remained largely stable over 6 months in treatment-naïve patients with early-stage POAG and OHT. PURPOSE: To compare the effects of selective laser trabeculoplasty (SLT) and topical latanoprost 0.005% treatments on macular and optic nerve head (ONH) microvascular parameters in patients with newly diagnosed early-stage primary open-angle glaucoma (POAG) and ocular hypertension (OHT), using optical coherence tomography angiography (OCT-A). MATERIALS AND METHODS: Sixty eyes of 60 patients with POAG (n=33) and OHT (n=27) were included and randomized into SLT (n=30) and latanoprost (n=30) groups. OCT-A measurements were obtained at baseline, week 2, and months 1, 3, and 6. Macular superficial capillary plexus vessel density (VD) was assessed using 6×6 mm scans, and radial peripapillary capillary (RPC) VD was evaluated using 4.5×4.5 mm ONH scans. Intra- and inter-group comparisons were performed. RESULTS: At week 2, intraocular pressure (IOP) levels were significantly lower in the SLT group than in the latanoprost group (P=0.033), with greater IOP reduction from baseline (P=0.031). Both groups showed significant IOP reductions at months 1, 3, and 6 (all P<0.001). At month 3, the increase in inferior hemisphere RPC VD was significantly greater in the SLT group (P=0.028), whereas at month 6, the increase in inferior hemisphere perifoveal VD was greater in the latanoprost group (P=0.028). Baseline IOP was strongly negatively correlated with 6-month IOP change in both groups (P<0.001), indicating greater IOP reduction in eyes with higher baseline IOP. CONCLUSION: Both treatments provided significant IOP reduction, while macular and ONH microvascular parameters remained largely stable over the 6-month follow-up. The clinical significance of this vascular stability requires further investigation in longer-term studies.