Central corneal thickness and corneal diameter in preterm and term newborns and preterm neonates at term

To record central corneal thickness and corneal diameter in preterm and term newborns within first week of their birth and in preterm neonates at term age.

Babies born at ≤34 weeks of gestation period (n = 100), term babies who have a gestation period of >37 weeks (n = 100) and preterm neonates at term age (38-42 weeks) who were born at ≤34 weeks (n = 100) were included in this hospital based observational descriptive study. Corneal diameter was taken by Castroviejo Calipers. Central corneal thickness was measured using portable ultrasonic pachymeter (Pachette 3). Refractive status of the eyes was measured using streak Wellch Allyn retinoscope under cyclopentolate cycloplegia.

Measure of central corneal thickness and corneal diameter in preterm newborns was found to be 633.5 ± 2.8 μm and 8.1 ± 0.6 mm, in full term newborns it was 555.1 ± 2.7 μm and 9.5 ± 0.6 mm, and in preterm neonates at term age, it was 563.5 ± 2.5 μm and 9.6 ± 0.5 mm, respectively. Mean central corneal thickness was found to be more in preterm newborns 633.5 um then term newborns 555.1 um and the difference was statistically significant (P =0.001). Mean corneal diameter was found to be maximum (9.6 mm) in preterm neonates at term age.

Preterm babies have thick corneas and small corneal diameters. This study is useful with respect to the analysis of glaucoma in children and using preterm corneas as donor corneas in penetrating keratoplasty.