Vision is more than seeing clearly. Seeing clearly is visual acuity and this is what is tested in a standard eye exam. Vision is the ability to perceive our environment, decode the information in it, and interpret it. It is a learned skill. From the day a baby can open their eyes in utero, they are learning to use vision to understand the world around them and their relation to the world. Impairments in vision impact how we use our body, how we learn and how we interact with others.
The visual system is incredibly complex so for this edition of the newsletter we will focus on one aspect – ocular motor control. This is how accurately, smoothly and quickly our eyes move from target to target. A child with ocular motor difficulties will struggle with near vision tasks such as reading. In this newsletter we will discuss saccades, smooth pursuits and eye teaming.
Signs of ocular-motor difficulties:
Saccades are very important for reading. This is the movement of the eyes quickly from one target to another. By the age of 6 a child should be able to perform this movement while keeping the head stationary. A child unable to maintain saccades will easily lose their place on a page.
Smooth pursuit movements is the ability for the eyes to closely follow a moving object. By the age of 6 a child should be able to track an object on the horizontal and vertical planes for about 60 seconds without having to move their head. Both types of eye movements should be sustained, smooth and symmetrical.
A child that has eye teaming issues, meaning their eyes do not move together to focus, may have convergence insufficiency, which will cause words to look blurry or doubled.
Reading for a child with ocular motor difficulties requires a huge amount of effort, resulting in fatigue and frustration. To compound this, most children do not know that their vision is impaired – they assume that everyone sees the same as they do.
Problems in ocular-motor control may become most apparent by the 3rd grade, when the print size decreases and reading demands increase.
Identifying and correcting deficiencies in the visual system early on can greatly improve academic outcomes and help to maintain a child’s self esteem and confidence. An examination by a developmental optometrist can identify these issues.
Some of the areas that can be worked on to develop more efficient ocular-motor control are certain primitive reflexes and the vestibular system. An underdeveloped vestibular system and an unintegrated moro, asymmetrical tonic neck reflex (ATNR) and symmetrical tonic neck reflex (STNR), can contribute to ocular motor difficulties as dysfunction in these systems inhibits the development of automatic movement patterns which support ocular-motor control.
The vestibular system works with the visual system to orient our body in space and helps us balance. An underdeveloped vestibular system will impact ocular motor control as well as coordination abilities.
An unintegrated moro results in sensitivity to head movements, such as looking up from a paper on a desk to a blackboard and leads to discomfort and fatigue.
ATNR promotes hand-eye coordination. When the baby’s head turns, the arm will extend on the same side, inviting the gaze to follow the arm. Non-integration of this reflex leads to midline issues. Knowing the midline of one’s body and crossing it is extremely important for overall body coordination and promotes integration of the hemispheres of the brain.
The STNR affects posture, gross motor coordination and binocular vision (using both eyes to look at a target in a coordinated manner). Children with this retained reflex will find it very hard to sit at a desk and may present as fidgety and unable to focus due to the discomfort they feel from sitting for a period of time. When this reflex is unintegrated it is difficult to disassociate the upper and lower halves of the body.
We hope you’ve enjoyed our newsletter on ocular-motor control. Let us know what you think in the comments below or suggest another topic for our next newsletter. You can also initiate services through our website or by giving our office a call on 832-727-3771.