Spotlight on Technology & Technique

Test Osmolarity With Increased Reliability

By Samantha Stahl, Assistant Editor

Despite the fact that dry eye is one of the most common ocular dilemmas, the irritating problem has lacked a reliable, user-friendly method for clinical diagnosis. Schirmer's strips have functioned as a stand in, but the test has its fair share of shortcomings. The TearLab Osmolarity System allows physicians to do an in-office test with rapid results, which proponents say are accurate and easy to acquire.

Objective Osmolarity

According to Marguerite McDonald, MD, FACS, a cornea specialist with the Ophthalmic Consultants of Long Island, the test is very easy to administer. “The company sends a technician to train the practice's staff. The skills transfer was rapid and uneventful.”

The TearLab Osmolarity System provides an in-office way to test for dry eye.

The test consists of a pen holding a small, disposable card that picks up around 50 nL of tear film at the tear meniscus, which is then placed in a portable, countertop system reader. The reader converts the tear fluid to an osmolarity score expressed in mOsm/L that is displayed on an LCD panel.

TearLab is now fully integrated into her practice: she uses it on any patient 40 years old or older, anyone with a history of dry eye or complaints of ocular surface irritation and all patients being worked up for eye surgery.

Dr. McDonald states that the test is clearly beneficial to patients, in the aid of dry eye diagnosis. It's also good for your bottom line. With no out-of pocket expenses for the patient, and simple disposable items used, “the system is definitely profitable.” The test is reimbursable for each card used, and the company's Web site provides full reimbursement instructions and support.

For testing aqueous tear production in dry eye patients, most physicians are used to Schirmer's strips, which can take 10 to 15 minutes to provide results. “We can run the TearLab test 10 times in the amount of time it takes to do Schirmer's testing, and as an added bonus the TearLab test is actually reimbursable,” says Christopher Starr, MD, a corneal and refractive specialist at Weill Cornell Medical College in New York City. “I have a very busy dry eye practice and being able to eliminate Schirmer's testing has vastly improved patient flow.” Not to mention that TearLab is less invasive, so patients are more comfortable with the test.

Patients with dry eye are, unfortunately, neglected by some physicians, only receiving advice to take artificial tears that do little to fix the problem. So when patients come in and are presented with new, objective technology to assess their symptoms, Dr. Starr says they respond positively. “It makes you look like a hero when you actually take the symptoms seriously and initiate treatment and measure efficacy based on objective data such as osmolarity.”

He likens a dry eye sufferer's osmolarity number to the way that diabetic patients get a hemoglobin A1c number at each doctor visit, and look forward to seeing the number come down to feel that they're getting better. “Being aware of their number and striving to lower it improves compliance with treatment, and empowers the patient,” he says.

The disposable tips require less than 50 nL of tear film to get an osmolarity reading.

Trusting the Technology

While the test has been shown to be reliable in studies, some MDs question its sensitivity when the results differ from their clinical diagnosis, which is often solely based on signs and symptoms. Dr. Starr recommends that these physicians should have more faith in the numbers and use them as a basis for clinical decisions.

“I'll see someone who has the symptoms of dry eye, but has normal osmolarity,” he says. “So I'll look more closely for dry eye masqueraders — allergies, medicamentosa and preservative toxicity, conjunctivochalasis and others. The test encourages me to look for other things, rather than being convinced that the machine is wrong and I'm right.”

With the DEWS report altering the definition of dry eye to include hyperosmolarity, the measurement is more significant than ever when making clinical decisions, says Dr. Starr. “For the first time, we have a noninvasive, objective way to get that number in the office setting. The TearLab test will improve care to patients in a number of ways.” OM

For more information, visit www.tearlab.com.