A biometric study of the eye, orbit, and face in 205 normal human fetuses.

PURPOSE: To develop models for assessing the differential growth of the fetal face along its horizontal and vertical axes, as well as of the orbit and the eye. METHODS: Normal human fetuses (n = 205), whose gestational ages ranged from 15.5 to 41 weeks of amenorrhea, were examined. Orbitofacial parameters were as follows: outer canthal distance, inner canthal distance, palpebral fissure length, and oropalpebral distance. Ocular parameters were corneal diameter and axial length. Correlations were tested among all parameters. Linear and polynomial regression analyses of gestational age and the orbitofacial and ocular parameters were used to develop models of growth. Differential patterns of growth in the face were investigated. RESULTS: The best correlation was found between palpebral fissure length and oropalpebral distance. The increase of each of the parameters studied could be accurately described by a linear model. Sex had no detectable effect on these parameters. Compared with the skull, the face had a more rapid growth along the vertical axis. The palpebral fissure developed more rapidly than the eye. CONCLUSIONS: The parameters that were studied in the fetal face, orbit, and eye follow a roughly linear growth curve.