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Published on: December 12, 2025
Defining reference values of trace elements in the tear film: diagnostic methods and possible applications
F Semeraro1, C Costagliola, A Cancarini
1Section of Ophthalmology, Department of Surgery and Forensic Medicine, University of Brescia, Brescia, Italy.
Ecotoxicology and Environmental Safety
|April 6, 2012
Summary
Tear analysis reveals significant differences in trace element levels between urban and rural populations. Arsenic (As) was higher in rural residents, while barium (Ba) and lead (Pb) were lower, suggesting tears as a potential biomarker.
Area of Science:
- Environmental Science
- Analytical Chemistry
- Toxicology
Background:
- Trace element exposure varies between urban and rural environments.
- Tear fluid is a potential biological matrix for monitoring environmental exposures.
- Previous research has not extensively explored tear analysis for trace elements.
Purpose of the Study:
- To investigate and compare trace element concentrations in the tears of individuals from urban and rural areas.
- To assess the feasibility of using tear analysis for biomonitoring of environmental exposure.
- To identify specific trace elements that show significant differences based on geographical location.
Main Methods:
- Tear samples were collected from apparently healthy subjects residing in urban and rural areas.
- Inductively Coupled Plasma Mass Spectrometry (ICP-MS) or Atomic Absorption Spectroscopy (AAS) was used for elemental analysis.
- Concentrations of chromium (Cr), arsenic (As), copper (Cu), zinc (Zn), selenium (Se), rubidium (Rb), barium (Ba), lead (Pb), and cobalt (Co) were measured.
Main Results:
- Significantly higher arsenic (As) levels were observed in tear samples from rural residents compared to urban residents (0.290 vs. 0.025; p<0.001).
- Conversely, barium (Ba) and lead (Pb) concentrations were significantly lower in rural residents (1.10 vs. 2.50, p=0.027 and 1.70 vs. 1.10, p=0.057, respectively).
- The study demonstrated the successful analysis of multiple trace elements in human tear fluid.
Conclusions:
- Trace element analysis in tears is feasible and can detect variations related to living environment.
- Tear fluid may serve as a valuable, non-invasive biomarker for assessing exposure to environmental trace elements.
- Further research is warranted to validate tear analysis for occupational and environmental biomonitoring.
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