The Clinical Signs and Symptoms of Optic Nerve Compression and Clinical Disease Entities Masking Compressive Lesions

The clinical signs and symptoms of surgically and autoptically proven lesions in the region of the optic canal vary considerably and may mimic any other suprasellar compressive lesion. The most frequent complaint is visual loss, which may be insidious, occasionally intermittent or rather acute. Slowly progressive visual loss is thought to be characteristic for slowly expanding or growing lesions, such as for instance meningeomas or pneumosinus dilatans, but it has also been observed in vascular lesions such as dolichoectasia or saccular aneurysms of the internal carotid artery (Michel 1877; Schloffer 1934; Mitts and McQueen 1965; Walsh and Hoyt 1969; Walsh 1971; Kennerdell and Maroon 1976; Hollenhorst et al. 1978; Wilson 1981; Miller 1982; Hirst et al. 1982, and others). On the other hand, meningeomas and pneumosinus dilatans may also cause intermittent, subacute or even acute visual loss (Torma and Koskinen 1961; Susac 1977; Wright 1980; Wilson 1981, and others). Acute visual loss is usually thought to represent a “vascular event”, and when it occurs with slowly growing or expanding lesions it is thought to represent a sign of hemorrhage into a pre-existing tumor, acute necrosis and edema, for instance in pituitary apoplexy, or a sign of compression of parts of the vascular supply, when the pressure reaches a critical level. In all cases immediate surgical decompression may restore at least part of the function.