Ultrasonography of the optic nerve

Abstract

The orbital optic nerve is extremely difficult to study clinically, as is the optic disc in eyes with opaque media. The combined use of quantitative A-scan and B-scan ultrasonography allows us to evaluate the intraocular and orbital optic nerve with a degree of precision and elegance not previously attainable. Disc cupping, elevation, drusen and many peripapillary affections may be demonstrated by ultrasonographic techniques. In the orbit. the optic nerve and its cerebrospinal fluid cuff may be studied and measured, and both intrinsic and extrinsic perineural mass lesions may be demonstrated. These techniques also allow for the differentiation of intrinsic neural masses from perineural tumors. In nearly all cases of orbital mass lesions involving or surrounding the optic nerve, a tissue diagnosis may be made with a high degree of reliability by ultrasonographic investigation. Ultrasonography is non-invasive, repeatable ‘ad lib’, and free of radiation or other iatrogenic sequelae.