Vision testing

During the first few years of life, visual development proceeds very rapidly and sets the baseline for vision in later life. Any problems at this stage that are not picked up can result in defects of vision that cannot be corrected later on. It is therefore essential that children have their eyes examined during this critical period to ensure that these can be looked for and treated.

Normal visual development

There are certain ‘milestones’ that help chart the progress of development of vision. Some of these include:

• 0-2 months of age: The baby develops fixing and following behaviour where in they focus on and track bright toys and lights. They develop a smiling response to parent’s faces (social smile) by the end of the first two months of life.
• 6-12 months: The hand eye coordination improves to allow recognition of objects in three dimensions which helps in grasping objects. This continues to evolve till 3-4 years of age.
• 2 years: The growth of the eyeball is 90% complete but the visual function continues to mature. By the end of the second year of life, the vision is almost equal to normal adult levels of 6/6 (or 20/20).
• 7 years: Marks the end of the critical phase of visual development. It is essential that any problems with visual development are detected and treated by this stage. Undetected eye conditions can have serious effects on children’s educational performance; poor concentration at school, worsening grades, distracted behaviour in the classroom etc. can be due to poor eyesight.

High risk children?

The incidence of refractive errors (the need for glasses for distance and near vision), squint (or strabismus where the eyes don’t point in the same direction) and lazy eye (or amblyopia where one eye sees more than the other) is around 4% in the general population but the incidence can rise to between 15-30% in certain high risk groups for whom visual screening is even more important. Some of these conditions include:

• prematurity (babies born before 32 weeks of age)
• problems with hearing
• family history of squints/lazy eyes/thick glasses
• down’s syndrome

Vision testing – when and by whom?

The Royal College of Ophthalmologists and the UK national Screening Framework recommend that every child’s vision be checked between 4 and 5 years of age. It is essential that the person carrying out these tests is experienced in examining and treating children.

Common problems and how they present

• White eye on photographs: A common finding in young babies and children is a white eye on photographs that may indicate an underlying disorder such as cataract or eye cancer (retinoblastoma). If this is seen on more than one photograph, it is a good idea to have this checked.
• Watery eye: It is not uncommon for babies to have watering from one eye and this usually clears by itself. However, if there is long standing watering and/or discharge from one or both eyes after birth, it can be cured by massage or minor surgery.
• Cysts on eyelids: Children can have recurrent episodes of small cysts on the eye lids that can persist for months at a time. In most instances, these respond to conservative management including hot compresses and antibiotic ointment. However, if they persist for a long time and/or cause visual or ocular symptoms, they can be removed very easily by a quick surgical procedure.