Retinal Microvascular Changes Associated with Concurrent Morphologic/Hematologic Response to Induction Therapy in Acute Leukemia: An Exploratory Prospective Wide-Field Swept-Source OCT Angiography Study

Background/Objectives: Wide-field swept-source optical coherence tomography angiography (WF-SS-OCTA) enables non-invasive, layer-specific retinal microvascular assessment. We explored treatment-associated microvascular change in acute leukemia and its concurrent association with post-induction response. Methods: In this prospective single-center cohort (ChiCTR2300077558), 111 newly diagnosed adults (58 AML, 53 ALL) and 40 healthy controls underwent pre-induction 16 × 16 mm WF-SS-OCTA; 77 were re-imaged at first response assessment. Response (complete remission (CR)/CRi vs. partial/no response (PR/NR)) was adjudicated independently of OCTA. The focal exploratory outcome was deep capillary plexus vessel density change (ΔDCP-VD). This outcome was designated after completion of data collection, and all analyses are exploratory and hypothesis-generating. Results: DCP-VD showed an AML < ALL < control baseline gradient (42.49 ± 3.15%, 43.45 ± 2.89%, 44.27 ± 2.78%; ANOVA p = 0.014), and 10 of 20 baseline metrics survived false-discovery-rate correction. ΔDCP-VD was higher in CR/CRi than PR/NR (1.50 (1.00, 2.00) vs. 0.50 ± 0.83 percentage points; difference 0.97, 95% CI 0.57–1.37; p < 0.01) and correlated with hemoglobin change (rs = +0.546, p < 0.01); in-sample discrimination gave an AUC of 0.799 (95% CI 0.674–0.907). Conclusions: ΔDCP-VD differed by concurrent response and tracked hemoglobin change; findings establish no causality, prediction, or clinical threshold and require independent prospective validation.