Researchers will investigate the distribution and evolution of amblyopia risk factors and other refractive errors in children younger than 3 years of age. The significance and magnitude of current global evolutions in ARF and refractive errors will be verified to update current guidelines and practices. Better insight in associated factors of amblyopia risk factors will contribute to current understanding of amblyopia.

The eye screening program of the Flemish governmental agency 'Kind en Gezin' is a well-implemented screening program for detection of ARF in children under the age of 3 years. This screening covers almost 85% of all children born in the Flemish community. Valuable information about distribution and determinants of refractive errors and ARF are collected at 'Kind en Gezin', but remain unstudied until today.

The aim is to analyze the distribution and evolution of refractive errors in children under the age of 3 years in Flanders. One supposes that identification of patterns in this distribution, and identification of determinants that influence ARF, will lead to improved knowledge about amblyopia (risk factors) and on their turn help optimize the ARF screening program. Evaluation of the distribution and evolution of refractive errors over time, and comparison with global results, will also give researchers insight in the significance of the myopia epidemic in Flanders.

Inclusion Criteria:

• We include all children with a PlusOptix screening between 2013 and 2018 with the age of 12±1 months or 30±1 months. Children who were screened twice, can be included twice with both screening results.

Exclusion Criteria:

• none

We include all children with a PlusOptix screening between 2013 and 2018 with the age of 12±1 months or 30±1 months.