Light-transmitting optical fiber having a core of a .[.deuterated acrylate.]. polymer .Iadd.selected from the group consisting of a deuterated methacrylate homopolymer, a deuterated methacrylate copolymer and a deuterated methacrylate/acrylate copolymer which .Iaddend.exhibits remarkably high transmission of light in the visible and at certain wavelengths in the near-infrared region of the spectrum.