Summary

Summary

The TearLab osmolarity system is a point‑of‑care device that measures the osmolarity of tears and is used to diagnose and monitor dry eye disease. The published evidence summarised in this briefing comes from 6 non‑randomised studies in adults on the value of osmolarity as a biomarker for dry eye disease. Four studies of limited quality showed that tear osmolarity either predicted dry eye disease or correlated with other dry eye tests. Two studies found no or limited correlation. The average cost for TearLab testing per person, including capital equipment and single‑use components, is £16.58 excluding VAT.

Product summary and likely place in therapy

  • The TearLab osmolarity system is a point‑of‑care quantitative diagnostic device that measures the osmolarity of tears for diagnosing or measuring response to treatment in dry eye disease (DED).

  • If adopted, TearLab would be used by optometrists or ophthalmologists in addition to existing tests for DED in a primary or secondary care setting.

Effectiveness and safety

  • The published evidence summarised in this briefing comes from 6 non‑randomised studies done in people with known or suspected DED and healthy volunteers.

  • Two of the 6 studies (n=36; n=288) evaluated the diagnostic accuracy of TearLab in adults with DED and healthy people as controls. They reported sensitivity ranging from 73% to 87%, and specificity ranging from 81% to 90%.

  • One of the 6 studies (n=36) compared osmolarity results from TearLab with those from the Clifton osmometer and found no statistically significant difference.

  • Four of the 6 studies showed a statistically significant relationship between osmolarity changes and severity of DED, and noted the value of TearLab as a valid diagnostic tool.

  • The results of 2 studies did not confirm the relationship between tear film osmolarity and the severity of DED.

  • No reports of adverse events were identified.

Technical and patient factors

  • The TearLab osmolarity system consists of 3 components: a pen, a test card and system reader. The pen holds the test card, which collects and analyses the tear fluid. The system reader displays the osmolarity measurement.

  • It is recommended that each pen is tested daily before use to ensure that the system is properly calibrated and working within the manufacturer specifications.

Cost and resource use

  • The TearLab reader and pen cost £4370 (excluding VAT).

  • Consumables (TearLab test cards) cost £323 (excluding VAT) for 40 cards. One test card is used per eye.

  • The cost per procedure is £16.58, including capital and consumable costs (excluding VAT).