ELECTROPHYSIOLOGIC ALTERATIONS IN PATIENTS WITH OPTIC-NERVE HYPOPLASIA

The clinical and electrophysiologic data (electroretinograms and visua l evoked potentials) were studied in 45 patients with optic nerve hypo plasia. The patients were divided into three fairly distinct groups on the basis of their electrophysiologic alterations. Group 1 consisted of 13 patients with almost extinguished visual evoked potentials and w ith mild electroretinographic alterations. These were the cases that a re traditionally recognized as optic nerve hypoplasia, The serious vis ual impairment in these cases was accompanied by various developmental ophthalmologic and nonophthalmologic abnormalities. Group 2 included 26 patients without any significant visual evoked potential or electro retinographic alterations, but with overt funduscopic signs of optic n erve hypoplasia. These patients were consistently suffering from strab ismus and/or amblyopia. The visual functions based on visual evoked po tential and electroretinographic recordings could be fairly normal apa rt from a pathologic ophthalmoscopic picture characteristic of optic n erve hypoplasia. Group 3 included six patients with abnormal albeit we ll-recordable visual evoked potentials and subnormal or negative-type electroretinograms that suggested an accompanying retinal disease. Thi s finding seems to prove that a subset of patients with optic nerve hy poplasia with nystagmus may have a primary retinal abnormality. Our st udy provides further evidence that optic nerve hypoplasia is not a uni form disease entity.