Flying Flies

Flying flies, French mouches volantes, Latin muscae volitantes (synonym myiodesopsia), an intraocular symptom characterized by the appearance in the field of vision of dark, more or less mobile spots (scotomas), bizarre in shape, resembling flies, spiders, etc. (hence the rarely used today term scotopsia). The origin of these scotomas is due to shadows cast by opaque particles in the dioptric media onto the retina; the greater intensity and mobility of these shadows indicate liquefaction of the anterior layer of the vitreous body (synchysis corporis vitrei) either on the basis of age-related nutritional and circulatory disorders (synchysis senilis) or on the basis of inflammatory processes of the vascular coat (synch. simplex). Flying flies of weak coloring, appearing mainly in the field of vision when looking at bright objects, represent shadows from dead elements of the vitreous body; this symptom is usually observed in the near-sighted (see Myopia).