Abstract
Purpose :
Tear fluid (TF) contains various electrolytes such as cations and anions, which may influence ocular surface disease including dry eye. Although cations in TF have been investigated to understand their roles, little is known about roles of anions due to insufficient measurement method. This study was conducted to establish a method to analyze the anions present in TF collected by Schirmer Strip and measure concentration of anions in TF of normal subjects.
Methods :
Since Schirmer Strip contains anions, a calibration curve using standard solutions of anions was used for correction of anion concentration. Forty healthy volunteers (mean, 32.6±11.9 years) were recruited. Anions in their TF were measured using a commercial ion chromatograph (IC-2010, Tosoh Corpo, Japan). TF was collected by Schirmer Strip, and the amount of TF was measured. Following centrifuge of tube with Schirmer Strip, eluted TF was diluted with 300 μL of pure water, and applied to the chromatograph.
Results :
We successfully monitored the concentrations of bromide, nitrate, phosphate, and sulfate anions (Br–, NO3–, PO42–, and SO42–, respectively) in TF collected by Schirmer Strip. Each anion of Br–, NO3–, HPO42–, and SO42– was detected in all samples, The mean concentrations (mg/L) of each anion were as follows; Br–: 7.55±1.96; NO3–: 3.39±2.44; PO42–: 119.07±138.98, and SO42-: 12.48±11.30mg/L. Concertation of each anion was not correlated to age. Concentrations of PO42– and SO42– was negatively collated to amount of TF. (PO42–: r=-0.881, p<0.001; SO42– : r=-0.845, p<0.001)
Conclusions :
We established a method to measure anion concentration in TF collected by Schirmer Strip. Both of PO42– and SO42– may relate to amount of TF, and be candidates of biomarker for dry eye.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.