Dry Eye Dx and Tx

Adopt Changes Today to Help Patients Tomorrow, Part 2

BY AMBER GAUME GIANNONI, OD, FAAO

Adding point-of-care testing to your screening armamentarium can improve your detection of dry eye disease (DED). Like all instrumentation, each has associated startup costs; however, their related procedures are billable lab tests.

Test Options

InflammaDry (Rapid Pathogen Screening, Inc.) – CPT 83516 We know that DED is associated with inflammation. One of the most studied inflammatory markers in the tear film is matrix metalloproteinase-9 (MMP-9), which is an enzyme produced by stressed epithelial cells. Higher concentrations could be indicative of more severe stages of DED (Chotikavanich et al, 2009). InflammaDry allows you to obtain a small tear sample from the palpebral conjunctiva with a collector that looks very much like a pregnancy test, and it gives results in a similar manner. If MMP-9 concentration is greater than 40ng/ml, a pink and blue line develops in the results window. Otherwise, only a single blue line appears. We use this test to help predict which patients will respond best to anti-inflammatory therapy.

TearLab Osmolarity System (TearLab Corp.) – CPT 83861 Increased tear film osmolarity is strongly correlated with DED severity (Foulks et al, 2009). With the TearLab system, you sample the tear film and know its osmolarity in seconds, all within a single test card. This can be used to routinely screen for dry eye as well as to monitor therapeutic effectiveness.

TearScan (Advanced Tear Diagnostics, LLC) – CPT 83520 (lactoferrin); CPT 82785 (IgE) Lactoferrin is a tear film protein that helps reduce microbial growth and maintain ocular homeostasis. It’s secreted by the acinar cells of the lacrimal gland and is considered to be a good biomarker for assessing gland function (Flanagan and Wilcox, 2009). TearScan analyzes a small sample of tears, collected via micropipette and transferred to a test cassette. There is an associated learning curve, but results are reliable once the technique is mastered. With a separate collection of tears, the TearScan can also measure Immunoglobulin E antibody (IgE) concentration, which is directly correlated to ocular allergy severity (Nomura and Takamura, 1998). In mild cases, allergy can be confused with dry eye, and both can be associated with inflammation, so TearScan can be a great differentiation tool.

Sjö (Nicox) – CPT 36416 Although not necessarily a point-of-care test, Sjö can provide new information to help diagnose Sjögren’s syndrome (SS) sooner than the current average of five years (Sjögren’s Syndrome Foundation, 2014). In addition to the traditional Sjögren’s biomarkers—anti-Ro/SSA, anti-La/SSB, RF, and ANA—three new organ-specific biomarkers are included: Anti-SP1 (produced by the lacrimal and submandibular glands), Anti-CA6 (produced by the submandibular and parotid glands), and Anti-PSP (secreted by the salivary glands) (Shen et al, 2012). The company says the cumulative specificity of these new biomarkers is 92%, which is substantially higher than traditional SS blood testing that carries a combined sensitivity and specificity of 40% to 60% (Tincani et al, 2013).

Conclusion

Some patients who have DED are asymptomatic; others have symptoms that don’t match clinical observations. Incorporating point-of-care testing in daily work-ups may help us begin to make more sense of this condition. CLS

For references, please visit www.clspectrum.com/references and click on document #228.

Dr. Gaume Giannoni is a clinical associate professor at the University of Houston College of Optometry and is the director of the Dry Eye Center at the University Eye Institute. She also sees patients in a private practice setting and has received authorship honoraria from Bausch + Lomb.