Intraocular pressure and central corneal thickness in premature and full-term newborns.

PURPOSE

To evaluate the intraocular pressure (IOP) and central corneal thickness (CCT) in premature and full-term newborns.

METHODS

IOP and CCT were determined in 33 premature (mean [± SD] gestational age 31 ± 3 weeks, mean birth weight 1474 ± 354 g) and in 33 full-term white newborns (mean gestational age 39 ± 1 weeks, mean birth weight 2763 ± 574 g). The mean age after birth at measurement was respectively 3 ± 1 weeks and 1 ± 1 weeks. Infants with any ocular abnormalities, such as corneal and iris alterations, congenital cataract, retinopathy, glaucomatous corneal and optic disk changes (horizontal corneal diameter >10 mm Hg, C/D >0.4), or familial congenital glaucoma were excluded. IOP was determined with the use of only topical anesthesia with a Tono-Pen XL tonometer and a wire lid retractor, and then CCT was determined by means of a portable pachymeter.

RESULTS

Mean IOP was 18.9 ± 3.7 mm Hg (range, 13-25) in premature and 17 ± 2.6 mm Hg (range, 12-22) in full-term newborns (P = 0.018 after correction by age after birth). Mean CCT was 599 ± 36 μm (range, 524-720 μm) in premature infants and 576 ± 26 μm (range, 489-650 μm) in the full-term group (P < 0.001 after correction by age after birth). Multivariate analysis showed that IOP increased with increasing CCT (P = 0.025) and that CCT declined with increasing birth weight (P = 0.026).

CONCLUSIONS

In premature newborns, IOP measurements were slightly greater than in full-term newborns because of an increased CCT.