Corneal diameter, axial length, and intraocular pressure in premature infants.

Abstract

Seventy premature infants 25 to 37 weeks' postconceptional age were examined during their first week of life to determine the correlation of corneal diameter, axial length, and intraocular pressure with gestational age and birth weight. Corneal diameter measurement was determined with corneal templates, total axial length with standardized A-scan ultrasound, and intraocular pressure with a Tonopen II tonometer. Corneal diameter and total axial length showed parallel linear increases from 6.2 mm to 9.0 mm and 12.6 mm to 16.2 mm, respectively; however, no significant correlation was found between intraocular pressure and gestational age or birth weight. The mean intraocular pressure was 10.3 mmHg (standard deviation, 3.5). Normative values are established for corneal diameter and total axial length as they relate to birth weight and gestational age, and a mean and standard deviation for intraocular pressure in the premature newborn. These values will aid the ophthalmologist in assessing ocular dimensions in premature infants.