April 2010
Volume 51, Issue 13
ARVO Annual Meeting Abstract  |   April 2010
Longitudinal Variability of Tear Film Osmolarity in Normal and Dry Eye Patients
Author Affiliations & Notes
  • D. C. Eldridge
    TearLab, Corp., Bixby, Oklahoma
  • B. D. Sullivan
    TearLab, Corp., San Diego, California
  • M. D. Berg
    TearLab, Corp., San Diego, California
  • M. A. Lemp
    Ophthalmology, Georgetown and George Washington U, Washington, Dist. of Columbia
  • D. S. Durrie
    Durrie Vision, Overland Park, Kansas
  • Footnotes
    Commercial Relationships  D.C. Eldridge, TearLab, Corp., C; B.D. Sullivan, TearLab, Corp., E; 7,017,394, P; M.D. Berg, TearLab, Corp., I; TearLab, Corp., E; M.A. Lemp, TearLab, Corp., I; TearLab, Corp., C; D.S. Durrie, TearLab, Corp., I.
  • Footnotes
    Support  Alcon Laboratories
Investigative Ophthalmology & Visual Science April 2010, Vol.51, 3379. doi:
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      D. C. Eldridge, B. D. Sullivan, M. D. Berg, M. A. Lemp, D. S. Durrie; Longitudinal Variability of Tear Film Osmolarity in Normal and Dry Eye Patients. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3379.

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      © ARVO (1962-2015); The Authors (2016-present)

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Tear film hyperosmolarity and tear film instability are recognized as the two causative mechanisms of dry eye disease, yet the relationship between the signs are poorly understood. The purpose of this study was to evaluate the variability of OD vs OS tear film osmolarity relative to tear film instability in the diagnosis of dry eye disease.


Bilateral tear osmolarity was measured on three different days, with at least two weeks between each patient visit. 30 subjects were recruited for the study (n = 16 normal, n = 14 dry eye). Subjects included in the dry eye cohort were determined by an average osmolarity > 308 mOsms/L. At each visit, 50 nanoliters of tear fluid was simultaneously collected and analyzed (both OD and OS) by the TearLabTM Osmolarity System in triplicate.


The average of normal subjects was 301.8±10.5 mOsms/L {range 290.2-307.7} while the average of hyperosmolar subjects was 315.6±18.6 mOsms/L {range 308.1-329.4}. The per-subject standard deviations were significantly different between the two groups (p << 0.001). Variability was strongly positively correlated with average osmolarity (r2 = 0.52), suggesting that tear film instability increased in dry eye disease. Of particular clinical interest, only 67% (56 of 84) of the tests performed on individual eyes were above 308 mOsms/L during the first measurement cycle on each day, whereas when the highest of either the OD or OS osmolarity result of an individual patient was considered, 81% of the dry eye subjects were correctly diagnosed during the first measurement cycle. By contrast 83% (80 of 96) tests on individual eyes were below 308 mOsms/L for normal subjects.


Variability in osmolarity is a hallmark of dry eye disease, reflecting the inability of the patient to maintain tear film homeostasis. It is recommended that physicians test both eyes to diagnose dry eye disease if the first value is less than 308 mOsms/L and the patient is symptomatic and/or dry eye disease is suspected.  

Keywords: cornea: tears/tear film/dry eye 

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