Provided are: a nucleic acid including a nucleic acid sequence encoding a chimeric protein including at least part of an ion-transporting receptor rhodopsin and at least part of a G protein-coupled receptor rhodopsin and a nucleic acid sequence encoding a signal sequence; and a nucleic acid including a nucleic acid sequence encoding a chimeric protein including at least part of an ion channeling receptor rhodopsin and at least part of a G protein-coupled receptor rhodopsin; and a nucleic acid construct including the nucleic acid sequences. The use of the nucleic acids or nucleic acid constructs prevents and suppresses the progress of retinal diseases, and enhances the visual cognitive behavioral function and visual function.