Multimodal Imaging of Yellow-White Transformation in Chorioretinal Hemorrhages: Structural and Biochemical Insights

Purpose: To investigate clinical and multimodal imaging characteristics of chorioretinal hemorrhages that undergo yellow-white transformation, focusing on optical coherence tomography (OCT) reflectivity and fundus autofluorescence (FAF). Patients and Methods: Sixty-five eyes with acute hemorrhage due to polypoidal choroidal vasculopathy (n=30), ruptured retinal arterial macroaneurysm (n=30), or retinal vein occlusion (n=5), which were followed monthly until resolution or transformation at Kyoto University Hospital between 2015 and 2016, were retrospectively reviewed. Lesion depth was classified on OCT as preretinal, subinternal limiting membrane, intraretinal, subretinal, or subretinal pigment epithelium. Reflectivity and FAF intensity were normalized against internal references and compared between red and yellow-white lesions. Results: Yellow-white transformation occurred most frequently in subretinal hemorrhages (18/47; 38.3%) and never within the neural retina. The mean time to transformation was 30– 40 days. Compared with red lesions, yellow-white lesions showed significantly higher OCT reflectivity (1.15 ± 0.33 vs 0.71 ± 0.29) and higher FAF intensity (1.13 ± 0.46 vs − 0.01 ± 0.24; both P < 0.001). Conclusion: Yellow-white transformation reflects structural and biochemical remodeling occurring outside the sensory retina, most often in the subretinal compartment. The consistent OCT and FAF signatures likely reflect accumulation of hemoglobin degradation products or phagocyte-derived material, and may assist in distinguishing hemorrhagic remodeling from other clinically white-appearing fundus lesions. Keywords: hemorrhagic remodeling, subretinal compartment, hemoglobin degradation, autofluorescence signature, reflectivity quantification