How vision develops in children

• Children’s eyes undergo significant growth during childhood and adolescence – both in size and function. 
• A range of vision problems are caused by refractive errors. Refractive errors refer to the focus power of the eye.
• Early detection and treatment of refractive errors with glasses and/or contact lenses maximises your child’s opportunity to enjoy  clear and comfortable vision for learning and lifestyle.

Visual acuity is the most commonly used measure of visual function. It describes the eye’s ability to clearly see  the features and details in an object. The most common cause of visual impairment results from a mismatch between the optical components of the eye, called refractive error. Refractive error usually refers to the “prescription” or “power” of the eye. When the eye is correctly powered and all the components of the eye match each other, vision develops normally. But when one or more of these components fall outside the normal range, refractive error results, which causes blurred vision. The optical components of the eye include the cornea (clear window at the front of the eye), focussing lens in the middle of the eye, and the total eye length from front-to-back.

Refractive error directly results in blurred vision, with the different types being short-sightedness or near-sightedness (myopia), long-sightedness or far-sightedness (hyperopia), and astigmatism.

In the first few years of life, normal eyes tend to follow a similar blueprint. At birth, most eyes initially have a moderate level of far-sightedness (hyperopia). As the eye grows and mature over time, the refractive error reduces in a process called “emmetropisation”.1 

Other than the prescription changing, the developing eye is learning to do many things better, such as:

• Focusing on objects at different distances (accommodation)
• Depth perception and seeing objects in three dimensions (stereopsis)
• Eye movements, such as changing focus between different objects (saccades), tracking a moving object (pursuits), and bringing the eyes together to focus on a close object (convergence)

By 6 years of age, most refractive errors will settle to a low to moderate level of hyperopia, or far-sightedness.2,3  It is important to note that it is far more common to be on the far-sighted end of the scale than short-sighted at 6 years of age. However, the proportion of children who have hyperopia depends on country and ethnicity.4 

Children with a higher degree of hyperopia at an early age can be diagnosed with focusing and reading disorders. This is usually corrected with glasses, sometimes with a specific prescription to assist reading and focusing up close.

Children may develop short-sightedness (myopia) during their school years. About 12% of children around the world have myopia,4  but this varies enormously by region. Myopia affects at least 60% of children in Asia, around 40% in Europe and North America, at least 20% in Australia and less than 10% in African and South American children.5 

Myopia typically develops between ages 6 and 12 and tends to worsen or progress every few months until the late teenage years.6  Myopia is a significant concern to vision-related quality of life in children, but also poses a risk to long-term eye health. Read more in What is myopia control and why it’s important. 

Many studies have highlighted that not spending enough time outdoors, coupled with a lot of close-up work, as reasons why short-sightedness develops and progresses.7  Myopia requires glasses or contact lenses to be worn full-time, to correct the blurred vision and because not wearing the prescription can speed up progression. These days, special types of glasses, contact lenses and atropine eye drops are available to slow down myopia progression. Read more in Which is the best option for myopia control?

Astigmatism is another common type of refractive error, affecting about 15% children worldwide.4  Astigmatism describes an uneven shape of the cornea, the clear window at the front surface of the eye, which causes light to be focused unevenly on the back of the eye. In most cases, astigmatism tends to be stable from childhood to adolescence and adulthood. Certain eye conditions, such as keratoconus, cause high degrees of astigmatism in children that tends to worsen over time. Glasses and/or contact lenses are used to correct the blurred vision from astigmatism.

Make an appointment to see your optometrist or eye doctor if you have any concerns about your child’s vision or eye health, including blurred vision, red eyes, sore eyes, or eye rubbing. They will be able to examine your child's eyes and diagnose any vision, focusing, or eye health issues. Vision and focusing problems can usually be remedied by prescription glasses and/or contact lenses. 

The important thing is to be aware of any potential signs of vision or eye health problems, and to see an optometrist or eye doctor if you have any concerns. Therefore it is recommended for children to attend eye exams regularly or as advised by the optometrist or eye doctor - typically, this means at least once per year throughout the school years. Learn more about regular eye exams in Do kids need regular eye exams?

Learn more about vision in children in our Knowledge Centre where you can see age-specific content on topics such as vision correction (glasses and contact lenses), eye health, screen time and more.