Products aimed at promoting visual skills cover a variety of skills related to the perception and interpretation of visual stimuli: visual acuity (sharpness of vision), depth perception (ability to perceive the distance between objects), hand-eye coordination (ability to coordinate hand movements with visual information), visual discrimination (ability to distinguish between shapes, colors, sizes, etc.), shape constancy (ability to recognize an object regardless of its position or size) and visual memory (ability to remember visual information).