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Comment & Response
December 2015

Progressively Increased Variation in Tear Osmolarity Mirrors Dry Eye Severity—Reply

Author Affiliations
  • 1Scheie Eye Institute, University of Pennsylvania, Philadelphia
JAMA Ophthalmol. 2015;133(12):1482. doi:10.1001/jamaophthalmol.2015.3860

In Reply Our study does not invalidate the utility of tear osmolarity as a biomarker of ocular surface disease, but rather raises questions about the clinical utility of measuring osmolarity using the TearLab system owing to the high variability of measurements at a single session and across sessions in both patients with dry eye and controls.1 We agree that there is substantial evidence regarding tear instability and hyperosmolarity in the pathophysiology of dry eye disease; however, much of the previously published research used different methods of measurement rather than electrical impedance as used in the TearLab system.

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