[A-scan-ultrasonography in unilateral optic nerve lesions (author's transl)].

With A-scan-ultrasonography it is possible to determine the time of transmission of ultrasound within the cross section of the distal optic nerve. In this way information regarding its thickness can be obtained. 156 patients with various unilateral optic nerve lesions were examined. Thickening of the affected nerve was found in the acute phase of neuritis nervi optici, trauma, optic nerve tumors and in papilloedema due to raised orbital or intracranial pressure. This investigation has proved a valuable aid in diagnosis in the following unilateral conditions: 1. Acute visual loss in the absence of significant fundus findings--an enlarged optic nerve ultrasonogram is an objective sign of a retrobulbar neuritis, or after injury, a haematoma. 2. Papilloedema--the optic nerve ultrasonogram gives information about the nerve. 3. Optic atrophy--an enlarged optic nerve ultrasonogram indicates an optic nerve or sheath tumor.