A lens-forming thermoplastic composition of matter has a crystallinity, as determined in accord with differential scanning calorimetry of from 0 percent to less than 1 percent when the composition comprises a hydrogenated vinyl aromatic/isoprene block copolymer or a crystallinity, as determined in accord with differential scanning calorimetry of from more than 0 percent to less than 1 percent when the composition comprises a hydrogenated vinyl aromatic/butadiene block copolymer. The composition has a birefringence, measured at a wavelength of 633 nanometers, within a range of from 0 to less than 6×10. Molding a melt of these compositions occurs at temperatures within a range from the hydrogenated block copolymer's glass transition minus 20° C. to the glass transition temperature minus 90° C. The compositions suitably form lenses such as an optical pick-up lens, which may be aspherical or have at least one of an irregular surface configuration, a non-uniform thickness or an irregular and non-uniform cross-section.