The procedure was less successful in eyes of children with bilateral NLDO compared with unilateral NLDO ( 63 % vs 80 % ; relative risk = 0.78 [ 95 % CI , 0.66-0 .92 ] ) and in eyes that had 2 or 3 clinical signs of NLDO compared with one ( 71 % vs 83 % ; relative risk = 0.88 [ 95 % CI , 0.81-0 .96 ] ) .