To establish a standard of normality, the authors studied the central and peripheral (superior, inferior, nasal, and temporal) corneal thickness of 152 healthy, white race, full-term newborns (304 eyes) between 1 and 6 days old, using ultrasonic pachymetry. The mean central corneal thickness (CCT) was 585 +/- 52 microns (ranging from 446-706 microns). The mean peripheral corneal thickness (PCT), significantly thicker than CCT (P = 0.0001), was: superior (SCT) 696 +/- 55 microns, inferior (ICT) 744 +/- 62 microns, nasal (NCT) 742 +/- 58 microns, and temporal (TCT) 748 +/- 55 microns. The SCT was significantly thinner than the ICT, NCT, and TCT (P = 0.0001). Differences among ICT, NCT, and TCT were not statistically significant. The mean CCT of the 1-day-old group was 611 +/- 58 microns, this being thicker than those of the other age groups (P = 0.0001). The differences between male and female babies and between right and left eyes were not statistically significant. This is the first study on peripheral corneal thickness at the limbus in the four meridians in live newborns.