Dr. Tole Greenstein received the Skeffington Award in 1973. This discussion is based on his writings for the Optometric Extension Program from 1967-8. The resultant monograph is entitled Optometric Child Vision Care and Guidance.
When young children learn how to manipulate objects with their hands, they must learn how to REACH for the object, and then GRASP onto the object. This allows the child to MANIPULATE the object and learn what it feels like and perhaps decide if it is familiar or not. Then the child must RELEASE the object in order to be ready to reach for something else and initiate this cycle once again. REACH-GRASP-MANIPULATE-RELEASE.
As children progress developmentally, they learn this same process utilizing the visual system. The child will reach for an object with the eyes instead of the hands; then grasp the object with the eyes in order to explore the object and determine what it is and what it means; then release the visual “lock” on this object in order to get ready to reach and grasp the next object worthy of “seeing.”
Many children with vision problems have great difficulty with this cycle of VISUAL Reach-Grasp-Manipulate-Release, especially the “grasp” part. They may be able to find an object with their eyes, but they have significant difficulty keeping their eyes on the target long enough to manipulate the object and figure out what the object is, what it means and how they might want to interact with it. Without grasping and manipulating, their visual processing is reduced to Reach-Release-Reach-Release.
This visual problem will be evident during very simple procedures to evaluate the quality of eye movements. The child will be asked to perform saccadic eye movements, which are jump eye movements from one object to another. These children cannot wait until they are instructed to jump to the other target; they cannot grasp the object. As soon as they reach the first target, they release and grasp on the 2nd target; then they release again and jump back to the 1st target; all this despite instructions to try to keep looking at the 1st target until told to look at the 2nd target. These children will make several round trips without ever visually grasping long enough to manipulate the object. When asked to fixate a small object, such as a small bell, and keep the eyes on the bell as it is moved into different positions, they have similar deficits. These children cannot maintain their grasp on the bell; they will release their grasp and look at something else: Reach-Release-Reach-Release.
What is the result of this inability to visually grasp and manipulate? Dr. Tole Greenstein described this as PERCEPTUAL MALNUTRITION. These children do a good amount of “looking,” but very little “seeing.” Without the grasp and manipulation, these children have very little useful information; very little visual “food” to feed their visual processing and thinking. How would a child with PERCEPTUAL MALNUTRITION behave in a classroom? When reading across a line of words in a book, they may never learn to identify the words. Every time they see words that are repeated on the same page, they are unable to use past experiences. Words strung together in a sentence have no meaning. Pieces have no relationship to a whole. Maps, graphs and diagrams are incomprehensible. What about the playground? How can these children react to a moving target if they can’t keep their eyes on the ball?
These children are often diagnosed with an oculomotor dysfunction, which describes their inability to perform age appropriately on the eye movement tests. Dr. Greenstein wrote, “it is important to talk about what the findings indicate that his life-world response in a given task would be.” The diagnosis of oculomotor dysfunction is meaningless unless you discuss the consequences. The resultant perceptual malnutrition and the inability to perform in and out of a classroom are of great consequence. Dr. Greenstein described vision therapy as a program of learning, teaching these children how to control their environment instead of allowing the environment to control them. The benefits of vision therapy will be different for every child. If you think your child may be suffering from PERCEPTUAL MALNUTRITION, find a developmental optometrist and start writing your child’s success story.