The present invention relates to a polymer composition comprising at least one polyamide and at least one urea compound of the formula I where x is 1, 2 or 3; R1 and R2 are selected from hydrogen, linear C1-C7-alkyl, branched C3-C10-alkyl, unsubstituted or substituted C3-C12-cycloalkyl, unsubstituted or substituted C3-C12-cycloalkyl-C1-C4-alkyl, unsubstituted or substituted aryl and unsubstituted or substituted aryl-C1-C4-alkyl; and Z is selected from C3-C10-alkanediyl, unsubstituted or substituted arylene, unsubstituted or substituted aryl unsubstituted or substituted ene-C1-C4-alkylene-arylene, unsubstituted or substituted heteroarylene, unsubstituted or substituted heteroarylene-C1-C4-alkylene-heteroarylene, unsubstituted or substituted C5-C8-cycloalkylene, C5-C8-cycloalkylene-C1-C4-alkylene-C5-C8-cycloalkylene, unsubstituted or substituted heterocycloalkylene and heterocycloalkylene-C1-C4-alkylene-heterocycloalkylene. This urea compound is used for improving the optical properties of the polyamide polymer composition. The present invention also relates to shaped articles obtained from said composition and to novel urea compounds.