Longitudinal evaluation of cotton wool spot following rapid glycemic improvement using wide-field multimodal imaging.

Purpose: To report a case of a diabetic patient undergoing rapid glycemic improvement characterized by the development and resolution of cotton wool spot (CWS), with detailed structural and vascular assessment using wide-field multimodal imaging, including wide-field color fundus photography and wide-field optical coherence tomography angiography (OCTA). Observations: A 47-year-old man with poorly controlled Type 2 diabetes mellitus developed CWS in his right eye 3 months after initiating insulin therapy, which coincided with a significant reduction in HbA1c levels. Wide-field color fundus photography and wide-field OCTA were performed before, during, and after CWS appeared. OCTA images revealed an absence of blood flow in the area of CWS during its presence, followed by reperfusion after its resolution. No pre-existing microvascular damage was observed in the area before the development of CWS. Conclusions and Importance: This case illustrates the potential the utility of multimodal imaging, combining wide-field color fundus photography and wide-field OCTA, as a powerful toolset for the follow-up and management of retinal changes in patients undergoing rapid glycemic improvement. These techniques provide comprehensive insights into retinal vascular and structural changes in diabetic retinopathy, with significant implications for both clinical practice and research.