Noninvasive assessment of tear stability with the tear stability analysis system in tear dysfunction patients

Invest Ophthalmol Vis Sci. 2011 Jan 21;52(1):456-61. doi: 10.1167/iovs.10-5292. Print 2011 Jan.


Purpose: To evaluate tear film stability in patients with tear dysfunction and an asymptomatic control group by using the novel, noninvasive Tear Stability Analysis System (TSAS).

Methods: In this prospective case-control study, 45 patients with dysfunctional tear syndrome (DTS) were stratified into three groups (1, 2, and 3/4) based on clinical severity, with higher scores indicating more severe symptoms; 25 asymptomatic control subjects were evaluated. TSAS measurements were performed with the RT-7000 Auto Refractor-Keratometer (Tomey Corporation, Nagoya, Japan). Images of ring mires projected onto the cornea every second for 6 seconds were captured and analyzed. Focal changes in brightness were calculated as numerical ring breakup (RBU) values, and the elapsed time when the cumulative values (RBU sum) exceeded a threshold was defined as the ring breakup time (RBUT).

Results: RBUTs in the DTS groups were all significantly lower than those in the control subjects, with the lowest values found in DTS 3/4. RBUT was significantly shorter in DTS 3/4 than in DTS 1 (P<0.001). The change in RBU sum over a 6-second period in the DTS groups combined or between the individual groups was statistically significant (P<0.001), as was the difference between the 1- and 6-second values. For distinguishing between asymptomatic controls and DTS, the sensitivity and specificity of a 5.0-second RBUT cutoff were 82.0% and 60.0%, respectively.

Conclusions: The TSAS may be a useful, noninvasive instrument for evaluating tear stability and for classifying DTS severity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Case-Control Studies
  • Coloring Agents
  • Cornea / metabolism*
  • Diagnostic Techniques, Ophthalmological / instrumentation*
  • Eyelid Diseases / diagnosis
  • Eyelid Diseases / metabolism*
  • False Positive Reactions
  • Female
  • Humans
  • Lissamine Green Dyes
  • Male
  • Meibomian Glands / metabolism*
  • Meibomian Glands / pathology
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • Sensitivity and Specificity
  • Sjogren's Syndrome / diagnosis
  • Sjogren's Syndrome / metabolism*
  • Surveys and Questionnaires
  • Tears / physiology*


  • Coloring Agents
  • Lissamine Green Dyes