The younger the child the more difficult visual assessment becomes.   But we have a variety of ways of assessing vision as it develops.

THe Development of Vision in children:

development of Vision in infancySlide5

These milestones can be delayed in children who are developmentally delayed. Assessing acuity objectively may be the only way to measure vision. Objective assessment of Vision

School age children:

Visual acuity may be assessed using the standard Snellen chart.

Preschool children (3-5 years): 

Visual acuity can be assessed using a modified technique.  The most successful and accurate technique is the Linear-Stycar technique. The patient matches, on a key-card, the letters displayed on a vision chart at 6 metres. see picture

linear stycar


Preverbal children:

The observation of behavioural patterns is the simplest method of assessment in this age group.  Further information can be gained by fixation and pursuit patterns when appropriate visual targets are shown.  Pupillary responses to light and optic kinetic nystagmus can also be used.   

At 2-4 weeks an infant will fixate and follow a light.

By 5-6 weeks a large object will be followed.

By 5-6 months small objects will receive attention.  Small toys, attractive objects,  (Smarties or 100s & 1000s) may be used to determine visual responses.

Preference of fixation with one eye is an indication of better vision in that eye.  A strabismic patient will alternate the fixing eye if vision is equal.

acuity smarties or smaller acuity 100s100s

 If no response is obtained subjectively vision can be assessed objectively Objective assessment of Vision