Objectives: To present normal lens and orbital measurement ranges by gestational age.
Methods: Three hundred and thirty-five women with uneventful pregnancies were evaluated from the 15th to the 40th week of gestation. Lens and orbital measurements were added to routine biometric measurements for normal fetuses.
Results: A strong linear correlation was observed between gestational age (GA) and lens diameter (R(2)=0.89; P<0.0001), circumference (R(2)=0.89; P<0.0001), and surface (R(2)=0.90; P<0.0001). A linear correlation was also found between GA and orbital diameter (R(2)=0.92; P<0.0001), circumference (R(2)=0.92; P<0.0001) and surface (R(2)=0.95; P<0.0001). A linear growth function was observed between biparietal diameter and both lens diameter (R(2)=0.90; P<0.0001) and orbital diameter (R(2)=0.94; P<0.0001).
Conclusion: Lens and orbital measurements provide normative data for fetal growth and development. These data may be also helpful in detecting fetal ocular anomalies.