Catalan Association of Optometry and Vision Therapy

Visual abilities

Before developing this section it is important that we differentiate two concepts:

-View: the eye’s capacity to see clearly from exactly 6 m.
-Vision: the interrelationship between the eyes and brain. Vision allows us to understand what we see. Vision is learned.

A visual system must have developed different skills to be effective. These skills are developed from birth. They can be classified into three sections:

Quality of vision: The ability we have to do with sharpness.
It is determined by the assessment of eye health and visual acuity.

Eye Health: A healthy eye is one that does not suffer any pathology; all those eye disorders that require surgical or pharmacological treatment.

Visual acuity (VA): The ability to discriminate details and assess the amount of view that we have with glasses, contact lenses or the naked eye. When visual acuity is less than 100% it may be due to eye disease or refractive errors such as myopia, hyperopia, astigmatism, presbyopia.

Visual effectiveness: Refers to the skills that allow us to perform adequately without displaying visual fatigue. It depends on the capabilities of accommodation, binocular vision and eye movement of the visual system.
Accommodation: There are changes in focus, that need to perform fast and accurately, to have a visual system that gives you the ability see clearly at different distances. An example is when children copy from a book or the blackboard or when we are driving so we can clearly see the controls of the car and the road. It is directly related to the ability to maintain visual attention.

Binocular vision: Integrating images of both eyes in the brain through proper coordination and alignment of the eyes fixed on the object. It provides three-dimensional vision. Problems such as strabismus, high foria and amblyopia (lazy eye) are called disturbances of binocularity problems.

Eye movement skill: The eye movements that allow the eyes to move quickly and accurately in different daily activities. They can be classified into three types:

Smooth pursuit movement: Those that allow us to effectively follow a moving object, such as ball games.
Saccadic eye movement: They serve to fix our gaze from one point to another efficiently. This depends on the distance between the fixed points may be of large amplitude (e.g. copying from the board) or of small amplitude (are those that enable fast and efficient reading).
Fixation: The ability to accurately maintain the stability of the fixation point that you are looking at with unnoticeable micro- movements of the eye. Visual attention may be altered if the setting is very unstable.

Information processing: Allows you to decode and correctly use the visual information. Visual information is processed in the brain in an area called the visual cortex. But there are 30 brain areas that are connected with this and each other, so it is important to have a good visual information processing to be integrated successfully with that of the other senses and allows the individual to properly interact with the world around him.
Visual-spatial ability: Relates to the visual location of objects in space. Difficulties in laterality and directionality can lead to confusion between concepts such as right - left, up - down, q - p - b - d, investment letters, etc.. which is often associated with an immature motor base.

Visual analysis skills: Refers to the ability to analyze and discriminate visual information. It can be classified into the following skills:

Form Constancy: The ability to perceive certain features of the forms.
Figure-Ground perception: Differentiates the figure of the surrounding background.
Visual Closure: Being able to perceive all the information even though the observed image is complete.
Visual Memory: Ability to recall information previously presented visually.

Audio-Visual Integration: Match the visual stimuli (letter) with auditory (phoneme). This will facilitate for example the reading pace.

Visual-motor integration: Most of our body's motor actions are guided by the vision (eye-hand coordination, eye-foot ...), which is why both systems should be well blended. Sporting activities or copying from the board's role are good examples of this integration.

The ability to decode and use visual information is related to the visual-spatial skills, of visual analysis, audio-visual integration and visual-motor.