VISUAL FIELD DEFECTS IN OPTIC DISC MALFORMATION WITH ECTASIA OF THE FUNDUS

In the ophthalmological examination of patients with neurological diseases perimetry is of outstanding importance. and not infrequently defects in the visual field are demonstrated in cases in which the differential diagnosis between cerebral and intraocular lesions causes difficulties, especially when the optic disc is involved. A voluminous literature exists on visual field defects in the presence of hyaloid bodies, pits and glaucomatous excavations of the optic disc. During my work in the Department of Ophthalmology, University of Aarhus, I have, in campimetry with small targets repeatedly observed a bilateral field defect in association with ectasia of the fundus and malformation of the optic disc. This defect, which is mentioned in the literature only in rare cases, may cause difficulties in the differential diagnosis from incipient bitemporal contraction of the visual field in diseases near the chiasma. Thus, in two of the cases reported below this led to the admission of the patients to the Department of Neurosurgery with the diagnosis of tumor of the pituitary body. However, the ophthalmoscopic findings will usually be so characteristic that the true nature of the changes in the visual field can easily be established. The ophthalmoscopic appearance of the dysplasia of the optic disc has previously been described under various names, e. g. Fuchs' coloboma, heterotypical crescent, inverse myopia, dysversion of the optic disc and inversion of the disc. When the disease has been accompanied by defects in the visual field it has been named posterior staphyloma, distorsion of the optic disc and scotomaka due to refraction anomalies. When the cases described in literature are considered collectively (Table l ) , various factors suggest that the cases re-