Atrophy of optic nerve fibres in compression of the chiasm. Prognostic implications.

A relationship between the degree of atrophy of retinal nerve fibres and visual field defect has been described in postoperative steady-state patients (Lundström & Frisén 1976). The same factors were studied prior to surgery in six patients with compression of the chiasm due to chromophobe adenoma. In five eyes the field defect was excessive in relation to the degree of atrophy. After surgery the visual field defects improved to a level corresponding to the degree of atrophy in these eyes. In the remaining seven eyes there was a close correspondence between the atrophy and the visual field defect already before surgery. The visual field defects remained unchanged in these eyes. Provided that atrophy does not increase after surgery, simultaneous preoperative evaluation of retinal nerve fibre atrophy and visual field defect allows an accurate prediction of prognosis for improvement.