By Eyecare NG
Visual skills are a group of skills needed for healthy and functional vision. They determine how well the two eyes work together (as a team) and how images perceived by the eyes are processed and interpreted. These skills are very important for learning especially for reading, writing and participation in sports. About 80% of what children learn is based on what they see and how that gets interpreted in their brain. Therefore any deficiency in visual skills can affect learning. Visual skills are not inborn but learned in much the same way as talking and walking. Many eye care professionals do not check for most of the visual skills during routine eye examinations as they tend to focus on visual acuity (how well you can see) and the structures of the eyes. Therefore, if you suspect learning-related vision problems in your child/ward, it is important to request that your eye doctor conducts visual skills tests or you consult an eye doctor who provides developmental/behavioural eye exams.
Visual skills include:
- Visual acuity
- Eye focusing
- Eye alignment and teaming
- Eye tracking
- Peripheral vision or peripheral vision awareness
- Depth perception
- Eye-hand coordination
- Eye body coordination
- Visual perception
- Vision integration
Visual acuity is the measure of how well the eye sees. It is usually tested by positioning a standard chart at a distance of 20 feet or 6 metres and asking the person to identify the letters or figures on the chart. Normal visual acuity is 20/20 or 6/6 which means that the patient was able to see at 20 feet (6 metres) the size of letters that are meant to be seen at that distance.
There are certain conditions that can affect visual acuity. They include (such as myopia, hyperopia and astigmatism) and other eye conditions and diseases like amblyopia, low vision, cataract, glaucoma and eye inflammations.
This is the ability to look at a specific object directly and steadily over a period of time. Good eye focusing skill enables you to see clearly as you change focus rapidly from one object to another or from one distance to another. When there is a spasm or paralysis of muscles involved in eye focusing or one has any other disorder that interferes with eye focusing, symptoms such as blurred vision, fatigue, headaches and brow aches while reading may be experienced.
Eye alignment and teaming
Eye alignment is the ability of the two eyes to focus on the same object at the same time without any of the eyes turning away from the point of gaze. Eye teaming, on the other hand, is the ability of the two eyes to work together as a team in a coordinated manner to ensure sustained single binocular vision.
Normally, the two eyes send images to the brain and these are fused into one resulting in single binocular vision. If there is poor eye alignment and/or poor eye teaming, there may be problems fusing the images into one and one may experience double vision as well as other symptoms such as frequent loss of place or tracking words with one finger or covering one eye while reading, poor handwriting, headaches, eye strain, poor depth perception and inability to sustain visual tasks.
Poor eye teaming can be easily diagnosed in those with strabismus (squint) since there is a visible misalignment of the eyes. However, non-obvious conditions like convergence disorders (disorders in the movement of the eyes towards each other) can cause poor eye teaming and these can only be detected during an eye examination.
This is the ability of the eyes to follow a moving object or switch fixation from one object to another accurately and quickly in a smooth and comfortable manner for as long as it is necessary. With good eye tracking, one can move the eyes accurately and smoothly along the line of print in a book while reading. This skill also permits accurate eye movements from the desk to the board and back. Dysfunctional eye tracking result in loss of place or jumping lines while reading, difficulty copying from the board and skipping letters or words while reading.
Peripheral vision and peripheral vision awareness
Peripheral vision is vision outside of one’s direct line of gaze. It is above, below and on the sides of one’s direction of gaze. Peripheral vision awareness, on the other hand, is the capacity to be aware of activities or objects outside one’s direct line of gaze without getting distracted by them. It enables people to be aware of what’s happening around them while they are engaged in something in front of them. This skill is the foundation for effectively carrying out many visual skills. Peripheral vision awareness is very important for activities like driving and sports where people may need to react to movements outside their direct line of gaze. Signs and symptoms of poor peripheral vision or peripheral vision awareness include bumping or brushing objects by your side, poor comprehension, decreased attention span and hyperactivity.
This is the ability to perform tasks that require simultaneous use of the hands and eyes. It the ease and accuracy with which the eyes guide the hands to write, draw, catch balls, make things, throw things, hold things and more. Most times these activities are not attributed to the visual system. However, if the eyes do not accurately inform the hands, these activities cannot be performed effectively.
Eye-hand coordination is a complex skill that unites the visual and motor skills. For instance, supposing you need a pen and there is one on a table near you, this how your visual and motor skills may work together: You will look around and see a pen on the table; your eyes will send this information to the brain and there, your visual and motor centres will coordinate to enable the brain to understand the exact location of the pen on the table; then you will move your hand to the exact location on the table and pick up the pen.
Eye-hand coordination is important for normal child development, academic success and good performance in sports. Problems with eye-hand coordination will cause developmental and learning problems, poor handwriting, poor attention, poor performance in sports and even difficulty with typing and driving.
This is the ability to perceive the world in three dimension and judge distances of objects accurately. With good depth perception, one can judge how near or far an object is. Depth perception is a very important skill in sports as it enables the player to judge accurately the distance of the ball, the position of other players and other targets of interest. Depth perception is part of binocular vision, hence it is affected by disorders like strabismus (squint) and amblyopia (lazy eye).
This refers to the brain’s ability to make sense of what the eyes see. It is a set of skills one uses to gather visual information from the environment and integrate them with other senses to understand what is being seen or experienced. Visual perception is a complex skill that involves:
- Processing what the eyes see to understand it.
- Organizing visual information
- Filtering out important information
- Determining the relationship between objects in the environment
- Recalling features of objects that have been seen before and in the order they were seen
- Locating specific objects in the midst of other objects.
- Identifying changes in objects that have been seen previously.
- Recognizing an object when part of the picture is missing.
Signs and symptoms of visual perception problems include lack of coordination and balance, difficulty learning left and right, reversing letters or numbers when writing or copying, difficulty performing activities involving rhythm, rotating body when writing or copying, having trouble learning alphabets and recognizing words, mistaking words with similar beginning, difficulty differentiating between letters like b, d, p and q , difficulty completing puzzles and more.
This is the ability to coordinate a set of visual information with another set of visual information or information from other senses to enable one make better sense of what is seen or to perform multiple tasks like reading while walking or hearing a sentence and writing it down.
Visual integration has 3 components namely, visual – visual integration, visual – motor integration and visual – auditory integration.
- Visual – visual integration: This involves bringing together two or more visual information to make better sense of what is seen. For instance, learning the spelling of an object and matching it with a visual image of that object can help one understand that object better and recall the name the next time it is seen.
- Visual-motor integration: This is the ability to coordinate visual information with motor skills. In this case, you use visual information to guide the movement of the body or parts of it. An example is eye-hand coordination where you use visual information to guide hand movement.
- Visual-auditory coordination: This is the ability to coordinate visual information with information that one hears (auditory information). When you see something and say it or you hear something and write it down, you are integrating visual and auditory information. Poor visual-auditory integration will result in poor spelling, problems with writing notes while the teacher is dictating, challenges matching sounds with letters and slow reading speed.