Believe it or not, vision and sight are not synonymous. Even with 20/20 eyesight, children, athletes and adults can have poor vision.
What is Sight?
Medically speaking, sight is the ability to decode light into electrical impulses as it enters the eye, and send the impulses to the brain.
In other words, sight is the eye’s ability to identify and process specific details. Optometrists evaluate eyesight by asking people to name letters on a poster from a distance, and assign a score based on the results. Sharp visual acuity improves one’s ability to discern details from a distance. People with poor eyesight must stand closer to need to stand closer to an object in order to notice these details.
What is Vision?
Vision is the ability to interpret and understand the information that comes in through the eyes to devise an appropriate response. The visual system utilizes brain pathways to process and understand what the eyes sense. Unlike eyesight, there are over 20 visual skills that are required in order to have a functional visual system, represented in every lobe of the brain, along with the cerebellum and brainstem – utilizing 65% of the brain’s pathways.
The dynamic process of vision is to identify, organize, interpret and understand what the eyes see. It then has to integrate with other sensory and motor information generated by the other senses to derive meaning and direct movement. Children without sufficient vision skills are often unable to participate effectively in school, and/or athletics, and may consequently develop learning issues.
Eyesight is genetic, and can change based on environmental factors. Vision, on the other hand, is a learned process that evolves over time. Vision develops from birth, based on our experiences, and our reactions to those experiences. Early on, people develop visual skills which evolve into more complex visual abilities. The most significant visual milestones take place during childhood. Other communication systems, such as speech and rhythm, are interdependent with – and develop alongside – the visual system.
As stated above, there are over 20 visual skills that are required in order to have functional vision. Properly developing each skill is crucial to the ultimate ability of the visual system.
Also called eyesight, visual acuity refers to how clearly one can see at both a distance, and up close. This ability is based on both ocular health and refractive error. Visual acuity is measured in the Snellen fraction, with a score of 20/20, or better.
Coordinated eye movements are central to proper vision. Eye movements, or ocular motility, describes how patients can fixate on a particular stationary target, follow moving targets along a path (pursuits), and transition from one target to the next (saccades).
As the distance between your eyes and the object of focus increases or decreases, your eyes need to maintain accurate optical power to preserve clarity. Accommodation is the ability to maintain focus on these objects, both up close and from afar. Visual focus is intimately related to the ability to sustain visual attention.
Vergence is the ability of the eyes to accurately point at the same place in space. Uncoordinated eyes can cause double vision or suppression, but also cause fatigability during vision related tasks, such as studying or reading.
Binocularity is the sensory ability to combine each eye’s visual interpretation of an image into one stereoscopic image. Using the image from each eye, binocularity allows the brain to put two images together, and construct a 3D environment. Without binocularity, the patient will not experience depth-perception.
Visual Information Processing
Visual information processing is the ability to interpret and organize what is seen. Visual perceptual skills include visual discrimination, visual memory, spatial relations, visual closure, and figure ground, amongst others. The difficulties that can arise from perceptual delays include poor spelling, difficulty learning to read, letter reversals, difficulty with mathematical concepts, poor memory, and poor reading comprehension.
Visual Spatial Skills
People naturally organize visual space based on directional concepts in relation to themselves. This involves using both sides of the body, as well as balance and understanding how various shapes can have different meanings when in different operations.
Deficiencies in one or many of these cognitive skills can lead to developmental or coordination issues.
Optometric vision therapy can improve these visual skills. Gold Coast Vision Performance can help lay the foundation for positive learning through unique, patient-focused treatment.