Pre and postoperative binocular vision (BV) was compared in long-standing large angle exo deviations. The purpose was to determine the BV potential in these cases and particularly for those at risk of postoperative paradoxical diplopia. In this retrospective study patients were grouped according to preoperative BV status. Group A had evidence of BV preoperatively with normal retinal correspondence. Group B had suppression on all tests. Group C had abnormal retinal correspondence. Twenty patients were identified with eleven in group A, five in group B and four in group C. Fusion and / or stereopsis was present in 17 cases postoperatively. The results demonstrate that constant large angle long-standing childhood onset strabismus does not preclude obtaining binocular potential postoperatively.