The invention provides compositions and kits including at least one nucleic acid or polypeptide molecule encoding for a mutant ChR2 protein. Methods of the invention include administering a composition comprising a mutant ChR2 to a subject to preserve, improve, or restore phototransduction. Preferably, the compositions and methods of the invention are provided to a subject having impaired vision, thereby restoring vision to normal levels.La presente invención se refiere a una molécula de polipéptido aislada, caracterizada porque comprende la SEQ ID NO: 26 en la cual el aminoácido en la posición 132 de la SEQ ID NO: 26 es cisteína (C) y el aminoácido en la posición 159 es cisteína (C) o serina (S).