A biometric study of the fetal orbit and lens in normal pregnancies

Purpose. To construct nomograms of the size of the fetal orbit and lens and to evaluate the relationships between the gestational age and the biometry of the fetal orbit and lens. Method. Six hundred two normal pregnant women were evaluated from 15 to 40 weeks of gestation. Fetal orbital and lens measurements were added to routine biometric measurements for normal fetuses. Results. A total of 595 measurements were used for analyses. A strong linear correlation was observed between gestational age and orbital diameter, orbital circumference, and orbital surface. A linear correlation was also found between gestational age and lens diameter, lens circumference, and lens surface. A linear growth function was observed between biparietal diameter and both the orbital diameter and the lens diameter. Conclusion. Orbital and lens measurements provide data that correlate with fetal growth and development. These data may also help detect fetal ocular abnormalities. © 2008 Wiley Periodicals, Inc. J Clin Ultrasound, 2009