The lipid layer and stability of the preocular tear film in newborns and infants

Abstract

Purpose: To measure the thickness of the precorneal lipid layer and the stability of the precorneal tear film in neonates and infants in the first 6 postnatal months.

Design: Prospective, observational case series.

Participants: One hundred ninety-eight neonates and infants in the newborn nursery.

Methods: The Keeler Tearscope Plus (Keeler Instruments Inc., Broomall, PA) was used to evaluate lipid layer thickness by interference fringe biomicroscopy and directly to measure noninvasive tear breakup time (NIBUT). The thickness was classified from level 1 (open meshwork-very thin) to level 9 (colored fringe pattern-very thick).

Main outcome measures: Noninvasive tear breakup time in seconds and classification level of lipid layer thickness.

Results: The mean lipid layer classification for all newborns was 8.3 +/- 0.9, with no significant difference between genders. The thickest classifications (levels 8 and 9) were found in 83.3% of all infants. At 3 and 6 postnatal months, all infants studied had a lipid layer classification of 9. Mean NIBUT was 32.5 +/- 5.2 seconds (range, 17.6-48.5 seconds) and was not significantly different whether stratified by race, postconceptional age, or birthweight. However, although NIBUT was longer in males at birth (35.1 +/- 4.2 seconds versus 29.4 +/- 4.5 seconds; P < 0.001), it was equal in both genders at 3 and 6 postnatal months.

Conclusions: In the first 6 postnatal months, the lipid layer of the tear film is much thicker than in adults. The NIBUT in newborns is prolonged compared with adult values. This thick lipid layer in infants provides stability that may help prevent the thin aqueous layer from evaporating.