[Infant ametropias and their evolutions (myopia, hyperopia, astigmatism)]. / Ametropies de l'enfant et leurs évolutions (myopie, hypermétropie, astigmatisme).

Infant ametropias are defined as the whole optic caracteristics of the eyeball which do not allow a clear vision whithout functional disorder. As the sensorial maturity is only achieved at 4 to 5 years, the limits of ametropias are variable before that age. The majority of ametropias is constituted as early as 9 months and may be detected by a refractive examination under cycloplegia. This situation is especially true for hyperopia and astigmatism. The more important are initial ametropias the more unchanged they remain. At 9 months, 1 infant out of 5 present a non-physiological refraction. From 4 to 5 years, 1 child out of 4 needs a refractive correction. Significant myopias are uncommon in infants. They generally appear between 7 and 12 years.