Several therapeutic concepts are in favour of the treatment of intermittent exotropia. The presented paper will try to answer the question, whether this leads to different results, by the review of the 1989 and 1990 cases of two centres. In the Munich Right Isar Eye Hospital (Centre II) during this period 72 patients (already published data) were treated by recession and resection eye muscle surgery against intermittent exotropia or decompensating exophoria. The 111 compared patients of the Department of Orthoptics and Pleoptics at the University Eye Hospital Kiel (Centre I), were mostly treated with bimedial resection procedures. Another difference: diagnostic occlusion and prism correction were done in the Munich patients. There is major evidence that there are two widely different clinical pictures incorporated in the diagnostic frame of the so-called 'Intermittent Exotropia'. In a third prospective group of patients (10/91-3/92), therefore, the prism-acceptance was evaluated.