Subthreshold laser treatment does not change choriocapillaris perfusion in patients with intermediate age-related macular degeneration

Purpose: To evaluate the safety of subthreshold laser treatment (SLT) at the level of the choriocapillaris (CC) using optical coherence tomography angiography (OCTA) in patients affected by intermediate age-related macular degeneration (iAMD). Methods: This is an analysis of patients included in the PASCAL clinical trial, including iAMD patients with reticular pseudodrusen (RPD). OCTA imaging was performed at baseline, 1-month, and 3-month follow-ups, focusing on a 3 × 3-mm treated area. The CC slab was segmented and analyzed quantitatively for flow voids using the Phansalkar binarization method. Flow voids in the treated area were compared to no-treated areas and analyzed across time points. Results: 20 patients (20 eyes) were included in the study. No significant differences in CC flow voids (%) were observed between treated and no-treated areas at baseline (27.9% vs. 24.6%, p = 0.641), nor were significant changes noted over time in treated areas (baseline: 27.9%, 1-month: 28.8%, 3-month: 32.6%, p = 0.115). Similarly, no-treated areas exhibited no significant alterations over time (baseline: 24.1%, 1-month: 24.3%, 3-month: 26.8%, p = 0.204). Conclusion: SLT did not induce detectable CC damage or alter perfusion in treated areas, further confirming its safety in managing RPD secondary to dry AMD. These findings support SLT as a viable therapeutic option, warranting further investigation to validate its long-term efficacy and safety.