REFRACTIVE ERRORS, AMBLYOPIA, AND DEVELOPMENT OF THE VISUAL-SYSTEM IN CHILDREN

Young infants show a wide range of refractive errors, including myopia and astigmatism, but during the preschool years most children become emmetropic. In some children the infantile myopia reappears at school age. Those children who retain astigmatism past the first year are at greater risk for developing amblyopia. Anisometropia is rarely found in children, leading to the question of how adults become anisometropic. Many studies indicate that amblyopia is underestimated when grating acuity tests are compared with recognition acuity tests. Modifications to existing testing procedures for measuring recognition acuity, such as adding crowding bars to letters and pictures, hold promise for detecting amblyopia in young children. Study of the early stages of development of visual function, when rapid changes occur, are particularly important since during this time the visual system may be prone to aberrant development.