The Clinical Utility and Usability of the TearLab Osmolarity System

The Clinical Utility and Usability of the TearLab Osmolarity System

Purpose: This study is intended to monitor the clinical utility of the new TearLab Osmolarity System and to assess customer satisfaction in the hands of its intended users, optometry and ophthalmology private practices and clinics, in the management of dry eye disease.

Methods: TearLab utility data was collected over a 12-month period (December 2009 through December 2010) in 25 eye care private practices (optometry and ophthalmology) in eighteen states (AK, AL, CT, FL, GA, IL, IN, KS, KY, LA, MD, MO, NH, NC, NY, OK, WI, WY).  During this time period, 639 patient encounters were recorded.  The type of patient that triggered a tear osmolarity test was recorded, including: dry eye symptoms, contact lens wearer, pre-surgical examination (Lasik, cataract or other refractive surgery) or a post-surgical examination.  Tear fluid osmolarity testing was performed and test results recorded.   Clinician impression was collected regarding whether the TearLab osmolarity test did or did not improve doctor /patient interaction and patient education and if the TearLab test did or did not improve patient compliance with dry eye treatment.  Finally, overall clinician satisfaction with the TearLab Osmolarity System was graded on a scale of 1-5, with 1= Not at all Satisfied and 5=Completely Satisfied.  Adverse events related to the TearLab test were recorded and reported.

Results: A total of 639 patient encounters were recorded, but all data was not always reported for all patient encounters.  Of patient encounters in which the dry eye symptom question was answered, 497 of 544 patients (91.4%) reported dry eye symptoms.  99 of 581 patients (17.0%) reported wearing contact lenses.  38 of 559 patients (6.8%) were tested as part of a pre-surgical examination and 36 of 551 patients (6.5%) were tested for post-surgical examinations.  378 of 629 patients tested (60.1%) had an osmolarity test result >308 mOsms/L in at least one eye.

• TearLab provided significant improvement in patient interaction & education. In 423 of 432 patient encounters (97.9%) the clinician reported that the TearLab test improved doctor/patient interaction and education.
• TearLab provided significant improvement in patient compliance. In 186 of 190 patient encounters (97.9%) in which treatment was a factor, the clinician reported improved patient compliance.
• Doctors were very satisfied with the performance of the TearLab. Of 429 patient encounters in which clinician satisfaction was recorded, an average satisfaction rating was 4.4 of 5.0, with 10 of the 429 encounters (2.3%) reporting satisfaction less than 3.0 of 5.0.
• No adverse events were reported. Validating the exceptional safety and ease-of-use of the TearLab Osmolarity System.
• Just because a patient has symptoms of ocular irritation, does NOT mean they have dry eye disease. 497 of 544 patients (91.3%) reported dry eye symptoms, which appears to have been the primary driver for the use of the TearLab test, as only 99 of 581 patients wore contact lenses or were pre- or post-surgical subjects, which occurred in only 38/559 and 36/551 patient encounters respectively. Osmolarity in either OD or OS was >308 mOsms/L in 378 patients of 629 tested, indicating that 60.1% of the patients had quantitative and objective evidence of dry eye. This is significant considering that 91% of the patients (497/544) reported symptoms of ocular irritation. Therefore, the TearLab played a critical role in distinguishing dry eye disease, which is a disorder of the lacrimal or meibomian gland, as compared to other types of ocular surface disease, such as allergy, Fuchs, EBMD, etc.

Discussion: The TearLab Osmolarity System provides the first quantitative and objective test for dry eye disease, giving both the doctor and patient a number to help assess the clinical situation.   In this study doctor/patient interaction was rated based on the value of TearLab osmolarity number in educating the patient on dry eye disease and its impact on patient compliance to dry eye therapy.  Also, type of patient tested, ease of use and overall satisfaction with the TearLab test was measured.

Overall clinician satisfaction with the TearLab was assessed on a scale of 1-5, with 1= not at all satisfied, and 5 = completely satisfied, resulting in an average satisfaction rating of 4.4 out of 5.0 in 429 patient encounters, indicting a high rating of satisfaction.  Only 10 patient encounters (2.3%) reported satisfaction on the lower half of the scale, indicating that 97.7% of the patient encounters provided a satisfactory experience with the TearLab.

Enhanced patient education is a key advantage to having a point-of-care diagnostic test and was a feature that the study evaluated.  To the question, “Did the TearLab test improve doctor/patient interaction and patient education?”, 97.9% of the time (423 of 432 patient encounters) the clinician answered “yes” confirming the value of the question, “What’s my number?” in the management of dry eye disease.

Also, compliance to treatment is always a challenge in a chronic disease such as dry eye, and knowledge by the patient that treatment efficacy would be measured at subsequent doctor visits led to the question, “Did the TearLab test improve patient compliance with recommended treatment?”.   For 186 of 190 patient encounters in which treatment was a factor, the clinician answered “yes” confirming that TearLab led to improved patient compliance 97.9% of the time. This is not an unexpected phenomenon, as primary care physicians have known for years that point-of-care laboratory testing, such as whole blood glucose and glycosylated hemoglobin tests, enhance confidence in therapy and increase patient compliance in diseases requiring both lifestyle and pharmacological therapy.  “In patients with chronic diseases a test may be used to assess the status of the patient and the effectiveness of the intervention, thus playing an important role in maintaining patient compliance.” ¹

While symptoms of ocular irritation are common, it has been shown that there is a lack of correlation between signs and symptoms, particularly in mild dry eye disease, rendering symptoms alone unreliable for diagnosis and determination of dry eye disease severity^2-6. The clinical presentation of dry eye disease is quite complex. Because the etiologies of dry eye are multifactorial in nature, physicians often fall back on a diagnosis of “Dry Eye Disease” for any non-specific ocular surface pain. The reality is that treating non-specific pain as dry eye disease may not help to improve the patient’s outcomes, and commonly leads to frustration for both the patient and the physician. Understanding if the patient has a stably low (normal) tear osmolarity can assist in determining whether it is best to look elsewhere for the cause of pain.

Chronic irritative stimuli from the ocular surface have been associated with neural plasticity as well as augmented second order neuronal and central nervous system effects⁷. In many cases of non-specific ocular surface pain, the tear film is functional but the nerves are overactive. In these cases, treating a dysfunctional tear film will not necessarily solve the patient’s problems, and the underlying neurogenic inflammation must be treated separately. These cases, which may not be dry eye at all, provide a difficult challenge for physicians. It is further complicated by the fact that a down regulation of nerves may result in a lacrimal insufficiency. Therefore, it is quite important to know whether the tear film is functional before a diagnosis is made.

Inappropriate management of patients based on symptoms alone can have a significant economic impact on the health care system. Better diagnosis of patients presenting with dry eye symptoms would increase patient satisfaction as only those patients truly having dry eye disease would be prescribed dry eye medication and have a significant positive economic impact on the health care system.

In independent studies, tear film osmolarity has been shown to be the single best marker of disease severity across normal, mild/moderate and severe categories⁸ and, as seen in this study, can play an important role in dry eye disease management.

Finally, of 639 patient encounters, over 12 months, no adverse events were reported, demonstrating the safety of tear collection using the TearLab Osmolarity System.

Conclusion: This study demonstrates that the TearLab Osmolarity System is meeting its intended objective in the marketplace – that is, to provide a simple and easy method to manage dry eye disease at the point-of-care, and to give the practicing clinician an objective and quantitative method to assess patient symptoms in order to improve patient and clinician interaction in disease management.

References:

1. Price C. “Point of Care Testing: Potential for Tracking Disease Management Outcomes” in Disease Management & Health Outcomes. Point of Care Testing; 2002; 10(12) – 749-761.
2. No authors listed. Methodologies to Diagnose and Monitor Dry Eye Disease. In: 2007 Report of the International Dry Eye WorkShop (DEWS). Ocul Surf 2007;5(2):108-123.
3. Clinch TE,Benedetto DA, Felberg NT, Laibson PR. Schirmer’s test. A closer look. Arch Ophthalmol 1983;101: 1383-6
4. Goren MB, Goren SB. Diagnostic tests in patients with symptoms of keratoconjunctivitis sicca. Am J Ophthalmol 1988: 106: 570-4
5. Schein OD, Tielsch JM, Munoz B et al. Relation between signs and symptoms of dry eye in the elderly. A population –based perspective. Ophthalmology 1997;104: 1395-401
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7. Belmonte C, Acosta MC, Gallar J. Neural basis of sensation in intact and injured corneas. Esp Eye Res 2004;78(3) :513-25.
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