In case of motility disturbances due to orbital fractures generally a vertical diplopia -- that means a vertical restriction of the motility of the globe -- is found. The classification into four types according to Friemel allows a differentiation between mechanical motility disturbances and those of other origin; furthermore a prediction can be made about the extent of the field of diplopia and about the involved position of gaze. In addition the urgency of a primary reconstruction of the orbit and the prognosis of a late eye muscle surgery can be estimated by this classification. It is of differential diagnostic importance that isolated injuries of the eye muscles and the check ligaments, an intraorbital haemorrhage and a subtotal paresis of the oculomotor nerve can show a similar clinical picture as usually found with orbital fractures. The early diagnosis of ocular motility disturbances caused by orbital trauma is of essential importance for the proper treatment and the recovery of binocular single vision.