Systems, methods, and apparatuses for amblyopia and ocular deviation correction, as well as visual interfaces, are disclosed. The transceiver comprises a receiver, a timing recovery circuit, a same-channel phase interpolator, an echo canceller, a near-channel phase interpolator and a near-end crosstalk canceller. The polyhydroxycarboxylic acid skeleton comprises optically-active monomers having an optical purity X of 80% by mole or less.