All ETDs from UAB

Advisory Committee Chair

Roderick Fullard

Advisory Committee Members

Mark Swanson

Tammy Than

Document Type


Date of Award


Degree Name by School

Master of Science (MS) School of Optometry


WITHIN SESSION REPEATABILITY OF THE TEAR LAB OSMOLARITY TEST AND CORRELATION WITH OTHER CLINICAL TESTS FOR DRY EYE PEARL SHIN DEPARTMENT OF VISION SCIENCES ABSTRACT Background The human tear film consists of three primary layers that work in conjunction to provide protection and nutrition to the cornea. When a layer is disrupted, the entire tear film loses its integrity and fails to function normally. Dry eye is the most common cause of tear film disruption. Among several methods to characterize dry eye is measurement of tear osmolarity. The TearLab Osmometer is commonly used clinically for this purpose. Previous studies in this lab with an early version of the TearLab showed a lack of consistency of repeat measurements and a limited range of osmolarity, preventing meaningful comparisons with other clinical test results. The current study investigated the reliability of a newer version of the TearLab and compares results with those of other clinical tests for dry eye. Methods Thirty participants were recruited for the study, which consisted of one 45-minute clinical visit. Participants completed an Ocular Surface Disease Index questionnaire followed by: visual acuity, six consecutive osmolarity measurements in each eye, non-invasive tear break-up time (NIBUT), Schirmer I test, anterior segment assessment with slit lamp, fluorescein and Lissamine green vital dye staining, and fluorescein tear break-up time (TBUT). Statistical analyses were run to explore the repeatability of TearLab measurements, to look for ordering effects and to compare results of individual and averaged measurements with other dry eye tests. Results The newer TearLab was significantly more reliable than the original version, but also showed a small range of values across a group of normal, aqueous-deficient and evaporative dry eye patients. The third osmolarity measurement correlated best to the mean of the rest for both the right and left eyes. For all ways of expressing TearLab results, no strong correlations were found with other clinical tests for dry eye. Conclusion Despite repeatable measurements, the TearLab osmometer lacked the dynamic range to differentiate between different types and severities of dry eye. It also lacked significant correlations with other clinical tests for dry eye. Other tests, apart from the Schirmer I test, showed better inter-test correlations.

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