Children with learning difficulties (attention deficit disorder) often have difficulty with attention and concentration. The difficulties can occur with reading, writing, comprehension, organization skills, memory, as well as with coordination, balance and movement. For children, vision is sometimes considered but only to be certain that the child can see clearly at distance. A vision screening in school by the school nurse and even in many pediatrician offices only will test how clearly the child sees at distance and not even at near range.
Vision is not often considered as a part of the difficulties unless the visual acuity at distance is found to be less than 20/30. This is unfortunate because underlying visual problems can and do occur in children even with 20/20 acuity and healthy eyes.
The eyes are often considered to be just like cameras that send information to the brain for the image to be seen. This is a ‘myth’ about vision and will lead many professionals to not understand that children can have clear vision but difficulty with visual processing in the brain. The visual processing dysfunction is caused by difficulties that occurred in child development.
During the development of the child the visual process organizes through interaction with the motor system through movement. As Arnold Gesell MD, noted child development researcher and clinician stated,” Vision emanates (develops from) from an action system”. Through the early stages of development the child develops and learns to balance two separate visual processes. One is for organizing information for posture, balance and movement. This has been called the spatial visual process. It is the first process the child is born with. It is the process that serves as the ‘platform’ for the higher visual process involving seeing images and relating information for reading, comprehension, memory, concentration and attention.
The spatial visual process serves as a ‘platform’ for the organization of the higher visual process much like a table serves to support dishes, papers, computers, etc. If the table does not have strong, stable legs then it cannot support the things that we put on top of it.
The spatial process serves to organize child for postural alignment so that the higher visual process, often called the ‘focal ‘ process can function effectively.
When there is a spatial visual processing dysfunction the child will often have vision problems with:
- Eye tracking
- Converging the eyes to look at objects or a book at close range
- Making quick accurate eye movements for copying or reading
- Focusing control of the eyes for reading and writing.
This can lead to symptoms such as:
- Loss of place when reading or reading words incorrectly or putting words in place of the correct word
- Losing focus
- Covering an eye if the is difficulty with alignment
- Poor posture causing leaning to the side or even placing their head on the table or arm when reading or writing
- Handwriting that lacks spacing or causes words to run into each other
- Handwriting that drifts off of the line
A visual processing dysfunction can lead to interference with higher processing affecting learning. Often difficulties with memory, comprehension, and attention, are caused by underlying visual processing dysfunction that, in turn, interfere with organization of visual skills affecting performance in learning. The visual processing dysfunction can also affect coordination causing some children to appear clumsy and uncoordinated. Depending on the type of visual processing dysfunction, it can cause some children to appear coordinated but not be able to sit still for attention and concentration in school. The lack of movement disrupts the organization and balance between the two visual processes.
It is important to assess not just the child’s eyes for health and clearness of vision but to evaluate the functional visual skills as a representation of the balance in visual processing. For example, if a child is having difficulty with maintaining their eyes in alignment or focus through convergence when reading or writing, it is necessary to assess how the child is organizing the spatial visual process.
At the Padula Institute of Vision Rehabilitation emphasis is placed at understanding the visual processing dysfunction that can cause the characteristics of difficulties with converging and focusing the eyes, as well as other visual skills necessary for organization of using vision for learning. A complete visual evaluation will often include a careful assessment of eye trackng , convergence and focusing. The refraction will evaluate whether the child needs corrective lenses to improve sight or clearness of vision. Dynamic testing of focusing will be performed during reading activities. In addition, it may be recommended to further evaluate how the child organizes these visual processes by conducting a visual evoked potential (VEP) which is a means of evaluating brain waves produced by the visual process and then evaluating changes that can occur with the introduction of special lenses. Since the process of vision evolves from organization with movement, the evaluation will often include an assessment of vision related to posture, balance and movement.
The result of this comprehensive evaluation may lead to specific recommendations for lenses (glasses) near and/or far vision activities. These lenses may include prisms to affect posture, balance and movement. In addition, Neuro-Visual Postural Therapy ™ (NVPT) may be recommended in some cases to re-organize the spatial visual process that is causing the learning difficulties and/or difficulties with coordination.