A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?

In terms of genetics, dominance is the occurrence where one copy of a gene on a chromosome expresses itself over and overrides the activity of another copy for the same trait. The first variation is referred to as dominant, whereas the second is referred to as recessive.

The colour of the eyes is a polygenic trait that is impacted by several genes.
The combination of dominant alleles produces the observed phenotype. There must be no dominant genes present, or one of two may be, for light eyes in both parents and offspring.
Although, It is impossible to determine whether a variant of a trait is dominant or recessive unless we are informed of its genotype. To reach any genotype-related conclusions, at least three generations must be analysed. 

So, the answers is no, we cannot determine if the light coloured eye trait is dominant or recessive.