The principles of diagnostic ultrasound and computed X-ray tomography are briefly described. The informations to be expected can be derived. First, the clinical use in determination of size and localization of the bulbus is discussed. This proved helpful in follow-up studies of buphthalmos, localization of intraocular foreign bodies and differentiation of pseudo-protrusion and protrusion (ultrasound exophthalmometry). The differentiation and localization of intraocular disorders (e.g. retinal detachment, intraocular tumors, vitreous hemorrhages, aqueous cysts) is facilitated. In space-occupying orbital disorders both methods complement but cannot replace each other. Therefore it appears that further development of ultrasonic diagnostic techniques should be promoted to reach at least the standards which are nowadays already achieved in computed X-ray tomography.