Handbook of Language and Literacy Development - a Roadmap from 0 to 60 Months

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Vision Development (7 - 60 Months)click to print Print
Research Review / Parent

Written by: Barbara-Ann Robertson, Sunita Shankar, and William R. Bobier, University of Waterloo

The extensive and rapid changes that took place in your child's visual system during the first 6 months of life do not continue to the same degree between 7 months and 5 years of age. However, this period in a child's visual development is when the eye and the brain begin to communicate more effectively and efficiently so that vision becomes more precise and more adult-like in many ways.

Changes in visual attention are now measurable as children are able to maintain and shift their attention at their own will. Learning what children want to look at helps determine what objects their freshly developed visual system can process. Refinements in brain development, and in the eye itself, continue until almost 4 years of age. Improvements in characteristics that allow for seeing fine details continue past 5 years of age.

How Vision Develops: Improved Communication Between The Eyes and The Brain

All of the groundwork for visual development was laid before your child's birth and during the first 6 months after birth. Between 7 months and 5 years of age there is continued growth and refinement of the connections of the visual system. This continued development and maturation of the visual system and its components make it possible for your child to see more and better as time passes.

Changes Inside the Eye

Even though babies are born with all of the necessary components inside their eyes to see, these components continue to develop until fully matured. As the baby grows the eye grows, and the components that make up the eye also grow and expand, and nerve connections are refined. This process of expanding and refining is what makes this period in development so remarkable. For some children this maturation process is finished by 15 months of age, while others continue to develop until around 4 years of age. Your child will continually see better and better, until his or her vision is almost adult-like. The fact that there is so much development, refinement, and rapid improvement occurring also makes this period quite sensitive to disruptions. Situations that disrupt vision such as large errors of focus, turned eyes, or opacities within the eye itself will reduce vision in that eye and it will remain so even after appropriate correction has been provided. The condition is known as amblyopia or "lazy eye". Often with early correction, spectacles, or surgery depending on the cause, amblyopia can be fully or partially ameliorated.

Changes in the Visual Parts of the Brain

The development of your child's brain is just as important to vision during the 7 month to 5 year time period as it was during the first 6 months of life. Between 7 months and 5 years the cortical areas of the brain develop. Having more well-developed cortical areas allows children to improve their vision, helping them to see both more and better. Your child can see motion and depth, contrast and colours better than he or she could before. As children examine different objects in the world around them, the connections between the eye and the brain are strengthened, allowing more and more complex information to be handled. This does not mean that exposing babies to complex visual objects improves their vision. Babies need only normal everyday experiences. If your baby or small child shows interest in particular objects, whether it is a teddy bear or a book, let the child examine it. Children are 'born to see', so do not worry about taking special steps to maximize your child's visual environment. Age-appropriate toys and normal play time (both inside and outside) are enough to ensure normal visual development. See (When and How to Contact an Eye Specialist)

How What is Seen Changes: Differences Over Time

Infants and Toddlers

Visual acuity, or how clearly one sees, continues to develop steadily during the 7 to 36 month period, so much so that by the time your baby is one year old, he or she can already see 10 times more clearly than at birth. Contrast sensitivity (the ability to detect objects as being different from a uniform grey background), also continues to improve over this period. Contrast sensitivity allows your child to detect fine details, texture, and allows for objects to appear different from surrounding objects. Infants' ability to detect objects as being unique from other things placed close by develops between 3 and 10 months of age until it is approximately half that of adult levels. However, their ability to detect fine details continues to improve but will remain below adult levels beyond 18 months of age. Preschool children are able to recognize letters at an adult level only if the letter is isolated from other letters or objects. Only when the child reaches 7 years of age can they reliably achieve adult levels of vision when reading a row of letters on an eye chart.

Being able to adjust the focus of the eye is the ability to switch from seeing something close-up to something far away or vice versa, fairly quickly. Errors of focus occur when the eye cannot do this accurately on its own, and then glasses are usually prescribed for older children and adults. However, in infants this age 'normal' vision is not what it is for adults. Typically infants and toddlers have greeter errors of focus than adults. These however have less impact since there ability to see is not as precise. Babies between 7 and 24 months of age also commonly have astigmatism; a distortion in focus. These focusing distortions will generally clear up with development during the toddler and preschool years. As the child's capacity to see approaches adult levels in the pre school years astigmatism also reduces to adult levels. By 36 months .These visual improvements happen normally. A paediatric eye exam can confirm that this is the case.

Preschoolers

An interesting visual effect called 'crowding' occurs in preschoolers. What happens is that preschoolers have more trouble seeing objects or letters presented amongst a "crowd" of other objects or letters than they do with just one object or a line of letters (like a sentence in a book). This effect is mostly gone by the age of 6 or 7 years. You may notice that your preschooler can identify single letters or pictures much better than he or she can pick out one letter or picture that is crowded by other letters or pictures. For example, your preschooler may easily identify an apple when it is the only picture on a page, but may have more difficulty when the picture of the apple is surrounded by pictures of other fruits.

A Special Note on Colour Vision

At a very young age infants can discriminate between colours. However, what is not known is how infants experience these colours. For example, what is 'red'? What do infants associate with the colour red? And does the infant see 'red' as they will when they are adults? Even though some of the first words children under 2 years of age learn are colour words, they cannot consistently identify colours until they are around 4 years of age. Even though your child can see colours and can tell the difference between colours, they cannot really experience those colours until they learn what they are called. Seeing different colours are important to your child's visual development. But just as with any normal visual experience, this does not mean children need to be bombarded with colours to 'improve' their colour vision. Normal exposure to the world around them will be more than enough exposure to colour.

Attending More Closely to the Visual World: Changes that Promote Learning and Interaction

Infants and Toddlers

After the age of 7 months, infants are able to shift attention from one object to another even if the objects are located at different distances apart. This ability to shift attention is very different from what was seen prior to 6 months of age when infants focused their attention on the most obvious object in view. Being able to shift attention is a result of all of the brain development that has been happening and your child's ability to do so will continue to improve.

This new development in your baby's ability to shift attention can result in a great deal of enjoyment for both you and your baby. By the end of the first year, if you point out an object to your baby, the baby should be able to follow your lead and also pay attention to the object. For example, you and your baby can enjoy seeing ducks swimming down a stream, watching a squirrel run up a tree, and watching a dog run across the backyard. At the same time, babies are able to pay attention to the details of an object rather than just to the whole object itself. This new ability may be unfortunate for any pets you may have at home when the cat's tail is discovered, or the dog's ear becomes of particular interest.

Preschoolers

The biggest change seen in attention in preschoolers is their ability to choose what they want to see. Preschoolers become good at controlling what they focus on, and at blocking out information that is not related to the task at hand. Children in this age group are also getting better at shifting their attention from one object or situation to another. Although your child might seem quite oblivious to the world around him or her at times, preschoolers developing the ability to play close attention to objects, people, and interactions when they want to and to shift attention if something more interesting happens. You may find that your preschooler can pay attention to a task for longer than he or she could before and may actually be interested in fewer activities than before because he or she now spends more time on each task rather than moving from activity to activity.

Robertson, B-A., Shankar, S., & Bobier, W.R. (2007). Parent/Caregiver Narrative: Vision Development 7 – 60 Months. In L.M. Phillips (Ed.), Handbook of language and literacy development: A Roadmap from 0 - 60 Months. [online], pp. 1 - 4. London, ON: Canadian Language and Literacy Research Network. Available at: Handbook of language and literacy development