Symptoms resulting from congenital nystagmus can be significantly reduced by wearing corneal contact lenses. A 90 minute therapeutic trial with contact lenses was performed on a 20-year-old affected patient and produced a beneficial effect. Upon removal of the lenses however the patient showed a transient rebound phenomenon with oscillopsia lasting about 20 minutes. This phenomenon, although it might be expected in theory, has apparently not previously been observed either because it is rare or because in most patients it is not clinically apparent. The purpose of this report is not to discourage treating patients with congenital nystagmus by means of contact lenses, but rather to draw attention to the occasional occurrence of such a rebound phenomenon and to discuss its theoretical significance.