Abstract
Purpose :
Changes in plasma hormone levels affect ocular surface functions. Whether hormone levels in the tears contribute toward ocular surface health is unknown. In this study, we optimized an enzyme-linked immunosorbent assay (ELISA) protocol to evaluate hormone levels in tears.
Methods :
Basal tear samples were collected from 7 adults with mild evaporative dry eye based on signs and symptoms (ages 20-34 years old, four females and three males, age-matched) with glass microcapillary tubes. The tubes were placed gently in the lateral tear meniscus and minimized contact with bulbar conjunctiva and lid margin to avoid reflex tearing. Approximately equal tear volume was collected from each subject. All male and female samples were pooled to achieve a high enough volume for detection. The testosterone Parameter assay kit (R&D Systems, Inc., Minneapolis, MN) was used to quantify testosterone concentrations in 20 μL aliquots of tear samples. The concentrations were analyzed in triplicate and calculated using the best-fit curve of the standard curve of the mean absorbance of each standard against the concentration. Non-parametric statistical analyses were performed using IBM SPSS Statistics (Ver 29).
Results :
Testosterone was detected and quantified in tear samples from both males and females. The average testosterone concentration in males was 0.22 ± 0.03 ng/mL, and in females was 0.21 ± 0.01 ng/mL. There was no statistically significant difference in testosterone concentration between males and females (U = 3.0, p = 0.7).
Conclusions :
Testosterone ELISA can detect and quantify testosterone in male and female tear film samples using a large tear volume. While this poses a challenge in collecting enough volume for individual analysis, using ELISA is an easy and relatively quick method for tear hormone analysis. Alternatively, pooling from multiple individuals or collecting from an individual at various times may resolve this challenge. More research with multiple hormone analysis is needed with a higher sample size and varied age and sex demographics to understand the connections between tear film hormones and the ocular surface.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.