The present invention relates to thermoplastic molding compositions, comprising a mixture composed of (A) from 30 to 69% by weight, based on the entirety of components (A), (B) and (C), of a methyl methacrylate polymer, (B) from 30 to 69% by weight, based on the entirety of components (A), (B) and (C), of a copolymer, obtainable via polymerization of a vinylaromatic monomer and of a vinyl cyanide, and (C) from 1 to 40% by weight, based on the entirety of components (A), (B) and (C), of a graft copolymer, obtainable from (C1) from 60 to 90% by weight, based on (C), of an agglomerated core based on a 1,3-diene, (C2) from 5 to 20% by weight, based on (C), of a first graft shell composed of a vinylaromatic monomer, of an alkyl methacrylate, and, if appropriate, of a crosslinking monomer, and (C3) from 5 to 20% by weight, based on (C), of a second graft shell composed of an alkyl(meth)acrylate polymer, with the proviso that the ratio by weight of (C2) to (C3) is in the range from 2:1 to 1:2, and it is inventively significant here that the core (C1) has monomodal particle size distribution, the average particle size D50 of the core (C1) (determined by the method mentioned in the description) is in the range from 300 to 400 nm, and the difference between the refractive index (nD-C) of the entire component (C) and the refractive index (nD-AB) of the entire matrix of components (A) and (B) is in the range from 0.003 to 0.008, each of the refractive indices being measured by the methods mentioned in the description, and also to a process for preparation of these molding compositions, to their use, and to the moldings obtainable therefrom.