Examination of the anterior vascular capsule of the lens: II. Assessment of gestational age in infants small for gestational age.

Between the twenty-seventh and thirty-fourth weeks of gestation, the appearance of the anterior vascular capsule of the lens (tunica vasculosa lentis) has been established to be useful in accurately estimating gestational age. Thirty-three infants assessed by maternal dates and Dubowitz scoring were studied with the direct ophthalmoscope following dilatation of the pupil in the first 24 hours of life. Five discordant twins, eight concordant twins, and twenty singletons were determined to be markedly small for gestational age on the basis of birth weight (less than tenth percentile). As in infants who are appropriately sized for dates, the disappearance of the anterior vascular capsule of the lens in infants who are small for dates correlates well with their gestational age and is reliable for gestational age assessment (p less than 0.0005).