cotton-wool spot

cotton-wool spot

white or gray soft-edged opacities in the retina composed of cytoid bodies.

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exudate

A liquid or semisolid which has been discharged through the tissues to the surface or into a cavity. Exudates in the retina are opacities that result from the escape of plasma and white blood cells from defective blood vessels. They usually look greyish-white or yellowish and are circular or ovoid in shape. They are sometimes classified into three groups according to size: (1) punctate hard exudates, which often tend to coalesce. They are found in diabetic retinopathy, Coats' disease, etc.; (2) exudates of moderate size, such as 'cotton-wool or soft exudates' as, for example, in branch/central retinal vein occlusion, hypertensive retinopathy, etc. These 'exudates' have ill-defined margins and are actually areas of ischaemia containing cytoid bodies, unlike hard exudates which are generally lipid deposits; (3) larger exudates, as found in the severe forms of retinopathy.