Evaluation of the effects of serum iron levels on lacrimal gland secretion.

In our study we aimed to demonstrate the relationship between the serum iron levels, and tears quality and quantity in term newborns. This study was conducted at a single institution between March 2013 and May 2013. A total of 46 newborns were prospectively enrolled. Serum iron levels were measured via the umbilical cord blood. Infants were divided into two groups according to their serum iron levels. Group A, serum iron level ≤70 μg/dL (n = 27) and Group B, serum iron level > 70 μg/dL (n = 19). The evaluation of the osmolarity was tested by using the TearLab Osmolarity System (TearLab Co, San Diego, CA, USA). The assessment of quantity was performed by using Schirmer I test. Osmolarity testing and Schirmer I test (with/without anesthesia) were performed bilaterally on the 1(st) day of life by an ophthalmologist. The outcomes of Schirmer I and tear osmolarity showed no statistically significant difference between right and left eyes of any infant in the groups. Moreover, there was no statistical difference between sexes in these two groups. Osmolarity was found to have a moderate negative correlation coefficient with serum iron level (r = -0.4, p < 0.01). Furthermore, there was a high positive correlation between Schirmer I with anesthesia and serum iron levels (r = 0.7, p < 0.01). We observed that the quality and quantity of the tears was lower in term newborns with lower serum iron levels than healthy newborns. These results indicate that low serum iron level could affect lacrimal gland functions.