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Published on: November 20, 2015
Development of tearing in preterm and term neonates
S J Isenberg1, L Apt, J McCarty
1Jules Stein Eye Institute, Department of Ophthalmology, Harbor-University of California-Los Angeles Medical Center, Torrance 90509, USA. isenberg@ucla.edu
Insights
Preterm infants show lower basal and reflex tear secretion compared to term newborns. Tear production increases with infant weight, reaching adult levels by term birth.
Area of Science:
- Neonatal Ophthalmology
- Ophthalmology
- Developmental Pediatrics
Background:
- Tear secretion capacity exists in both preterm and term infants.
- Previous studies have not prospectively assessed basal and reflex tear secretion together.
- Understanding tear production patterns has clinical significance for newborns.
Purpose of the Study:
- To quantify basal and reflex tear secretion in preterm (30-37 weeks) and term (38-42 weeks) newborns.
- To investigate the developmental trajectory of tear production in infants.
- To compare tear secretion between preterm and term neonates.
Main Methods:
- Schirmer tear test strips were applied to the inferior fornix for 5 minutes.
- Measurements were taken before (reflex + basal) and after (basal) topical anesthetic application.
- Seventy infants (36 preterm, 34 term) were included in the study.
Main Results:
- Mean basal tear secretion was 6.2 mm in preterm and 9.2 mm in term infants.
- Mean reflex tear secretion was 7.4 mm in preterm and 13.2 mm in term infants.
- Both basal and reflex tear secretion increased significantly with infant weight (P<.001).
Conclusions:
- Preterm infants exhibit diminished basal and reflex tear secretion.
- Reduced tear secretion in preterm infants may complicate diagnosis of nasolacrimal duct obstruction and lead to dry corneas.
- Tear production in term newborns approximates adult levels.
Background:
Although term and preterm infants have the capacity to secrete tears, the relative contribution of basal and reflex secretion of tears has not been previously assessed together in a prospective study. This information potentially has practical clinical importance.
Objectives:
To measure basal and reflex tear secretion in preterm (30-37 weeks after conception) and term (38-42 weeks) newborns and to determine the developmental pattern of tear production.
Methods:
Tear secretion was evaluated by applying Schirmer tear test strips to the inferior fornix for 5 minutes before (reflex plus basal secretion) and after (basal secretion) applying a topical anesthetic agent.
Results:
Seventy infants (36 preterm and 34 term) were tested. Mean (+/- SD) basal tear secretion was 6.2 (+/- 4.5) mm in preterm and 9.2 (+/- 4.3) mm in term infants and increased progressively with increasing weight (P<.001) for all newborns. Mean (+/- SD) reflex tear secretion was 7.4 (+/- 4.8) mm in preterm and 13.2 (+/- 6.5) mm in term infants and also increased with increasing weight (P<.001) for all newborns.
Conclusions:
Preterm infants have reduced reflex and basal tear secretion. This may mask the diagnosis of a nasolacrimal duct obstruction, concentrate topically applied medications, and allow corneas to quickly become dry during ophthalmological examination and treatment. By term, tear production in newborns is similar to that in adults.
