Two techniques to evaluate visual acuity from the age of 18 months.

Two methods to measure visual acuity in children aged 18 months and upwards are described, the Kolt-test and the O-test. The validity of the tests was evaluated. These new tests are based on the ability of small children to identify symbols of increasing complexity as they grow older. Thus, a circle is recognized at 12 months, and a cross at about 24 months, while recognition of a triangle and a square comes in between. Correct performance is rewarded. Simplified procedures permit testing children with visual acuity below 0.1 (6/60, 20/200). The tests may also be used in mentally retarded persons if conventional methods fail.