Sensory System Series: Visual System
You all probably know about our visual system, but did you know the only organ more complex than the eye is the brain?! Our eyes are very complex and hold many functions in order for us to see and process our surroundings.
The visual system is our sense of sight allowing us to see, observe, make connections, and interpret the world around us through our eyes. Our eye consists of several structures working together to take the visual information in our environment and form it into an image. This image is then converted into electrical signals that are sent to the brain to be processed via the optic nerve. Signals carry information about light, color, and shape. The stimulus triggering this process for vision is light or the change in light.
Vision provides time and spatial information. Through our day, we see a lot of visual information in a certain order within a volume of space. The visual system allows us to process this huge amount of information for us to function in our day. One important thing to know is that vision is not the same as eyesight. Eyesight is a prerequisite for vision and is our ability to see a certain item in our environment. We can either see it or we can’t. Vision, on the other hand, is a skill we are not born with and have to develop as we grow up to make sense of what we seet. We do this by movement and exploring our environment. Our visual system is integral to learning and impacts our everyday functioning. In fact, 75-90% of classroom learning depends on vision.
Basic visual skills:
Acuity- ability to see details of objects
Accommodation- ability to focus on objects near and far
Detection of movement- knowing things are moving and the direction of their moving
Binocularity- two eyed vision; the ability to use both eyes together as a team
Ocular-motor- eye movements; stay tuned for upcoming blog.
Furthermore, vision plays a vital role in visual perceptual and visual motor skills to facilitate optimal functioning in our everyday life. Visual perception is the ability to recognize, recall, discriminate, and make sense of what we see. Visual motor is the ability to coordinate visual information with motor output.
Other sensory systems influence our visual system. During movement, our muscles and joints are working accompanied by head movements stimulating our vestibular system and proprioceptive system. For example, we always look before we sit down so we don’t fall. We strengthen our visual skills when we move around and change positions. Additionally, the tactile system helps us integrate visual information. When we touch items, we see and feel the different elements of the item enabling us to visually picture or identify the item in the future. Lastly, the auditory system affects our vision. During conversations, you can picture what you are hearing and attach meaning to it to understand and have a meaningful conversation. For example, when you hear coffee, you can picture a nice cup of coffee. Also, our auditory system provides information about spatial awareness (where we are). Think about the game “marco polo.” We hear someone calling and change our direction to move close to the sound. The integration of our sensory systems improves our visual skills and visual processing.
A child with sensory processing disorder may have challenges with processing visual input. Their visual system may be over-responsive (hypersensitive) or under-responsive (hyposensitive). Over-responsivity means one has a larger than expected emotional or behavioral response to sensory input. It takes little input to produce a sensation. Visual over-responsivity, also called visual defensiveness, means a child reacts greatly to environmental stimuli others may not react as greatly too, such as reflections, shiny surfaces, bright lights or flickering lights to name a few. Also, being distracted by moving objects or busy environments.
On the other hand, a child may be under-responsive where the child has low arousal where they don’t notice the sensory input and it takes a lot of input to produce a sensation. A child with visual under-responsivity seems unaware of ordinary visual input or doesn’t respond quickly to things coming towards them. A child with sensory processing disorder may also seek intensive visual input. They love watching TV or being on the computer screen or being attracted to bright and/or flickering lights.
As I mentioned above, the visual system is complex and there are a multitude of functions and skills involved in processing visual information. Stay tuned for upcoming blogs to learn more about the role of visual perceptual and visual motor skills!
Therapeutic Tool Highlight: Night Light Projector
This lamp provides a multisensory experience through visual and external auditory stimuli. Brightness and color can be adjusted to suit the needs of your family and it connects to any bluetooth device to double as a speaker to play calming music. Neutral colors are more calming which can help with emotional regulation. You can also play a bedtime story at night or nature sounds to help your child fall asleep.
We hope the above strategies are helpful and if you need more or have questions, let us know! We are here to support you!
Check out our sensory system handouts you can purchase individually or as a bundle on our website! A great resource to learn about sensory processing disorder and each of our sensory systems. BONUS: print them off and hang them on the wall for all who pass by to view and learn or share with family, friends or teachers for them to have insight into your child’s sensory system.
Photos:
Top: http://www.tulsaeyedoc.com/childrens-vision/
Group of kids: https://www.beckenhamoptometrist.com.au/school-childrens-vision/