Visual Motor System
The ability to have “eye-hand coordination” is an essential process of the visual motor system. In animals, this ability is necessary for survival, particularly when trying to eat, drink, and make shelter. The visual motor system in humans also allows us to write, craft (e.g., draw, color, cut, glue), build, drive, dress, cook, play sports, and play video games. Vision is used to bring information about the external environment to the brain. When an individual moves, vision provides the brain with feedback information about how accurate and successful the person’s intentional (voluntary) movements were. The brain will then use this information to adjust the person’s actions to correct errors and to improve eye-hand coordination.
There are three main steps necessary for successful and efficient eye-hand coordination: (1) strong visual skills that are developed by the ocular motor system, which in turn are interpreted by the brain (also termed visual perception skills); (2) well-defined fine motor skills; and (3) integration of visual and fine motor skills together to perform the visual motor task.
Anatomy and Physiology
The ocular motor system controls eye movements as well as eyelid closure, the amount of light that enters the eyes via the extraocular muscles, and the refractive properties of the eye via the intraocular muscles. Together these muscles work in concert to guide vision and to maintain a stable image of an object on the retina. There are six extraocular muscles (three pairs for each eye) that contract or relax to control eye movement, while the levator palpebrae muscle is used to close the eyelid.
Since only a small part of the retina is responsible for visual acuity (sharp vision)—called the fovea centralis—it is essential for the eyeball to move so that it can track an object and maintain its clarity on the retina. Thus, the eye must move quickly as well as have very precise movements. For example, as you are reading this entry, your eyes are moving across the page and at the same time the words stay in focus. This shifting of gaze is produced by the extraocular muscles. Some of these movements are intentional (voluntary) and others are automatic (involuntary). However, research is needed to better understand how voluntary and involuntary eye movements are integrated by the ocular motor system to perform these actions. It is known that the vestibular system does play a role in involuntary eye movements through the vestibulo-ocular reflex.
Fine motor skills is a term describing coordinated actions of small muscle groups. Most often the term is used to describe the coordination of the wrists, hands, and fingers in completing very specific tasks, such as holding a knife and fork, catching a ball, or writing with a pen. Fine motor skills depend on (1) the core strength of the hand and fingers, and (2) proprioceptive processing skills, which determine the location of the fingers in space and the strength needed by the hand and fingers to manipulate objects to perform the precision of a task like buttoning a jacket.
Integrating visual skills with fine motor skills is a task that begins around three months of age in humans. This is when infants begin to grasp a caretaker’s finger with their hand. However, at this young age it is more of a reflex than a voluntary action. Over time the reflex becomes voluntary and intentional in reaching and grabbing for toys or other objects. Using vision, infants will begin to determine how far away an object is and how to adjust their reach to grab the item. By age three, children will have been working on their eye-hand coordination and begin to improve their fine motor skills with prewriting. Drawing lines and shapes and coloring will help toddlers integrate their ocular motor skills (following the shape of a circle with their eyes) with their fine motor skills (drawing or copying a circle on paper).
Visual Motor Activities
There are many activities that one can perform daily to improve one’s visual motor system and skills. Some include: (1) practice making shapes with different media—pipe cleaners, toothpicks, or string; (2) color—outline the picture to help see where to keep the crayon for coloring; (3) put jigsaw puzzles together—looking at the shape and color of the puzzle piece will help improve ocular motor skills, while putting the pieces together will improve fine motor skills; and (4) cut out shapes and paste them together to make a picture.
Jennifer L. Hellier
See also: Proprioception; Retina; Visual Perception; Visual System
Dragoi, Valentin. (2015). Ocular motor system. In John H. Byrne (Ed.), Neuroscience Online, an electronic textbook for the neurosciences (Chap. 7). Retrieved from http://neuroscience.uth.tmc.edu/s3/chapter07.html
Phelan, Shannon. (2015). Visual motor integration: What is it and how to develop this skill. North Shore Pediatric Therapy. Retrieved from http://nspt4kids.com/parenting/visual-motor-integration-develop-skill/