Vision is the use of light entering our eyes to interpret our environment, plan our actions and direct our movements. How easily we achieve this is determined by our ability to control and coordinate the complex mechanisms of our eyes to capture the parts of the visual field we deem important and by our ability to skilfully process and act upon that information.
Visual Efficiency - the skills used to capture the information
Visual Acuity (Eyesight Clarity)
The ability to clearly see objects. This may be affected by myopia (short sightedness), hyperopia (long sightedness) and astigmatism (differing amounts of myopia or hyperopia within the same eye).
Accommodation (Eye Focusing)
The ability to change where your eyes focus quickly, easily and accurately and to sustain this clear image for periods of time.
Binocular Vision (Eye Teaming)
The fusion of the visual input from each eye into a single and stable image. The ability to comfortably use both eyes together as a team without one eye wanting to turn in a different direction with the consequent loss of the visual information transmitted by this eye.
Signs and Symptoms of poor accommodation and binocular vision skills include:
Headaches and/or sore eyes when reading or writing
Blurred vision
Double vision
Decreased attention for near visual tasks
Close near working distance
Letters/words overlapping in reading
Eye burning sensations or watering
Inability to see 3D special effects
Oculomotor Control (Eye Movement Control)
The ability to maintain steady, accurate fixation on a target whether stationary or moving. To be able to change fixation quickly and accurately from one target to another at a variety of distances and locations.
Signs and Symptoms of poor oculomotor skills include:
Excessive head movement when reading
Skipping lines when reading
Omitting words and word transpositions when reading
Loss of place when reading
Using a finger or marker to keep place when reading
Confusion during the return sweep phase of reading
Illusory text movement
Deficient ball skills
Visual Information Processing - the skills used to process and act upon the information captured by our eyes
Information received from the light entering our eyes is combined with information gained from our past experiences and memories; this enlarged pool of information is then integrated with our auditory and motor abilities to enable us to formulate a plan to move our bodies a certain way to achieve a particular goal.
Visual Spatial Orientation
This is the ability to understand concepts involving direction for our own selves as well as for objects or other people. We understand and are aware of our own position in our environment relative to other things and also the position of other things relative to each other. We have the ability to control and use both sides of our body in a coordinated manner using our knowlege of our bodies.
Signs and Symptoms of Visual Spatial Orientation problems may include:
Poor balance or coordination
Clumsy, falls, bumps into things
Difficulty with sports
Unsure of left and right
Confuses directions
Reverses/transposes letters/numbers
Visual Analysis Skills
These skills are necessary to analyse and discriminate visually presented information.
Visual Discrimination - Awareness of the distinctive features of forms such as shape, orientation, size and colour. Signs of visual discrimination problems are confusing similar objects, words and colours.
Visual Figure-Ground - Attending to a particular feature or form while maintaining an awareness of the relationship of this form to the background information.
Visual Closure - Awareness of clues in the visual stimulus that allow determination of the final form without having to have all the details present. Signs of difficulty with visual closure are confusing similar words/objects, being slow to complete tasks and exhibiting poor comprehension.
Visual Memory - Ability to recognise and recall visually presented information, sequencing and visualisation (to mentally manipulate a visual image). Important for spelling, word recognition, reading comprehension and maths.
Visual Attention - Ablility to maintain attention on tasks. A sign of poor visual attention is being easily distracted from the task at hand.
Visual Processing Speed - The amount of time taken to analyse and interpret visual information. Slow speed can interfere with the automaticity of reading, copying from the board and completing tasks within a normal timeframe.
Visuomotor Integration
The ability to combine visual information processing skills with fine-motor movement e.g. eye-hand coordination. Difficulties in this area appear as poor pencil grip/writing, poor organisation on the written page, poor copying/spacing and poor ball skills.
Screening of vision information processing skills is performed if the case history indicates a problem in this area.
