Hydrogen ion concentration of tear fluid in newborn infants

Area of Science:

• Ophthalmology
• Neonatology
• Physiology

Background:

• Tear pH is a crucial indicator of ocular surface health.
• Understanding normal tear pH in newborns is essential for diagnosing potential ocular conditions.
• Previous research on neonatal tear pH is limited.

Purpose of the Study:

• To determine the normal tear pH range in newborn infants.
• To establish a reliable method for measuring tear pH in neonates.
• To investigate factors influencing tear pH in newborns.

Main Methods:

• Tear pH was measured in 173 newborn infants using a microcombination glass pH probe.
• The probe was immersed in the tear fluid within the closed lower conjunctival sac.
• Data was collected and analyzed for median and mean pH values, along with interpercentile ranges.

Main Results:

• The median tear pH was 6.8, with a 95% interpercentile range of 6.2 to 7.2.
• The mean tear pH was 6.74 +/- 0.26 (SD).
• Tear pH was not significantly related to infant age (within 12 days), mode of delivery, or silver nitrate application.

Conclusions:

• The microcombination glass pH probe offers an easy and reliable method for assessing tear fluid pH in newborns.
• This study provides valuable reference data for normal tear pH in neonates.
• The findings may enhance the understanding of tear function in both normal and pathological neonatal ocular conditions.