In vivo histology of cotton-wool spots using high-resolution optical coherence tomography.

PURPOSE: To provide optical characteristics of cotton-wool spots (CWS) on optical coherence tomography (OCT) and scan the retina after CWS have ophthalmoscopically disappeared. DESIGN: Observational case reports. METHODS: We studied four eyes of four patients with retinopathy due to human immunodeficiency virus (HIV) and hypertension. The StratusOCT Model 3000 in single-line mode was used for imaging of acute and resolved CWS and adjacent normal retina. The fundus photography served as a template for OCT scanning in localization of CWS. Retinal tissue reflectivity images were compared. RESULTS: There were differences in reflectivity of normal retina, the retina in the area of active CWS, and the retina in the same area after CWS has resolved. Most striking was that the OCT documented a persistent focal area of hyper-reflectivity in the area of the resolved CWS, indicative of retinal gliosis that could be imaged. CONCLUSIONS: CWS show a hyper-reflective pattern on OCT that persists even after they become ophthalmoscopically invisible.