The ornamental design for a visiontherapydevice, as shown and described.
FIG. 1 is a front view of a vision therapy device of the present invention, showing my new design;
FIG. 2 is an isometric view of a vision therapy device of the present invention, showing my new design;
FIG. 3 is an isometric view of a vision therapy device of the present invention, showing my new design;
FIG. 4 is a left side view of a vision therapy device of the present invention, showing my new design, the right side view being a mirror image thereof; and,
FIG. 5 is a top view of a vision therapy device of the present invention, showing my new design, the bottom view being a mirror image thereof.