Male, 64 years. Main complaint: slight vision deterioration. General medical history: BMI 24.9, non-smoker, arterial hypertenson since 20y, diabetes Type II since 20 y, HbA1c 6.7%. Purpose: To characterize the structural abnormality associated with retinal ischemia during a cotton wool spot episode, and the time course of three years. Findings: Image in 2009: Ophthalmoscopy showed a cotton-wool spot superior of the optic disc resembling an edema of the retinal nerve fiber layer, and several retinal hemorrhages. Image in 2012: Three years later, the cotton-wool spot completely vanished. After improving systemic therapy and focal retinal Laser coagulation retinal microinfarct was vanished. Discussion: Cotton wool spots (CWS) are associated with a wide range of systemic diseases such as diabetes and hypertension. An isolated CWS is believed to be caused by an acute focal occlusion of a single retinal arteriole. The reduced perfusion in the inner retina causes ischemia of the nerve fiber layer which in turn disrupts axoplasmic flow. As a result axoplasmic debris accumulates in the retinal ganglion cell (RGC) axons, and this is thought to interfere with signal conduction. This build up of debris is visible ophthalmoscopically as a reflective “cotton wool spot”. It was reported (1) that the borders of visually salient field anomaly mirrored the quantitatively measured relative scotoma. Results of high resolution perimetry and high resolution imaging indicated that a cotton-wool spot is a substantial loss of retinal ganglion cells within the affected region. A disruption in retinal nerve fiber arrangement is regularily found at the cotton wool spot and within the arcuate relative scotoma. It is suggested that the arcuate relative scotoma is consistent with the failed signal transmission along the axons that pass through the cotton wool spot. Literature: (1) Chui TY, Thibos LN, Bradley A, Burns SA.The mechanisms of vision loss associated with a cotton wool spot. Vision Res. 2009 Nov;49(23):2826-34.