A longitudinal study of the biometric and refractive changes in full-term infants during the first year of life

Changes in ocular axial dimensions and refraction were followed longitudina lly, using ultrasonography and retinoscopy, during the first year of life ( mean ages 4-53 weeks) of a group of 20 full-term infants (10 male, 10 femal e). Using a mixed-model regression analysis, axial length changes as a func tion of time were found to be best described by a quadratic expression (AL = 17.190 + 0.128x - 0.0013x(2), where AL is the axial length in mm and x is the age in weeks), while anterior chamber depth changed linearly (ACD = 2. 619 + 0.018x, where ACID is the anterior chamber depth in mm): lens thickne ss was essentially constant. Spherical equivalent refraction through most o f the first year showed a steady reduction in hypermetropia (SER = 2.982 - 0.032x, where SER is the spherical equivalent refraction in dioptres): asti gmatism also tended to diminish. Mean hyperopic refractive errors through t he year were negatively correlated with corresponding axial lengths (SER = 12.583 +/- 0.541AL), but some individual subjects showed marked departures from this pattern. These results are discussed in relation to concepts of e mmetropization. (C) 2001 Elsevier Science Ltd. All rights reserved.