Osmolarity Measurement and the Effective Diagnosis and Management of Dry Eye Disease
Release Date: October 1, 2011
Expiration Date: December 31, 2012
ESTIMATED TIME TO COMPLETE ACTIVITY:
Acknowledgement of Commercial Support:
An unrestricted grant was received from TearLab for this CME enduring material activity. This support was used for the production of the activity only, with no influence from TearLab on the planning or development of the content. As referenced, this osmolarity measuring system is one of a kind; however, multiple diagnostic options are listed.
Principal faculty and their credentials:
Eric D. Donnenfeld, MD, FACS; Michael A. Lemp, MD; Richard L. Lindstrom, MD; Marguerite B. McDonald, MD, FACS; Jay S. Pepose, MD, PhD; and Christopher E. Starr, MD, FACS.
Dry eye is a disease of the tears and ocular surface that results in fluctuating vision, tear film instability and increased osmolarity that can cause serious damage to the ocular surface. The condition, commonly encountered in clinical practice, affects upwards of 20 percent of the North American population.1 Hyperosmolarity is the primary cause of damage to the ocular surface in dry eye disease, as it induces apoptosis, inflammation and reduced lubrication of the ocular surface. Tear osmolarity has been shown to have a direct linear relationship to increasing severity2 of disease and can be used to both diagnose and manage dry eye disease. Because of the inherent instability of the tear film in dry eye disease, the osmolarity of both eyes must be tested using the higher of the two results to determine diagnosis and disease severity.
The goal of this activity is to educate physicians on current theories and methods of managing patients with dry eye disease.
- Tomlinson A. Epidemiology of dry eye disease. In: Asbell P, Lemp MA, eds. Dry Eye Disease: The Clinician’s Guide to Diagnosis and Treatment. New York: Thieme, 2006:1–15.
- Sullivan BD, Whitmer D, Nichols KK, et al. An objective approach to dry eye disease severity. Invest Ophthalmol Vis Sci. 2010;51(12):6125–6130.
This educational activity is intended for comprehensive ophthalmologists interested in the care and management of patients suffering from ocular surface disease.
Upon completion of this activity, participants should be able to:
- Explain the need for practitioners to go beyond patient-reported symptoms when diagnosing dry eye disease.
- Describe the diagnostic workup for dry eye disease.
- Describe the role of tear osmolarity in dry eye.
- Discuss the findings of recent research on dry eye and tear osmolarity measurement.
- Recognize opportunities for measuring osmolarity in various patient populations.
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Dry eye affects as much as 20 percent of the North American
population and is a condition with which ophthalmologists are all too
familiar.1 In dry eye disease, the tear film becomes compromised and
unstable, reducing both the quantity and quality of tears.2 As noted in the
Dry Eye Workshop Report, an increase in tear osmolarity is a hallmark of
dry eye disease and is thought to be the central mechanism in the
pathogenesis of ocular surface damage in the disease.3 The concept of tear
osmolarity has been around in ophthalmology for a long time. Abnormal tear
osmolarity is a failure of homeostatic osmolarity regulation and elevated
osmolarity can cause less regulation of the tear film, more damage to the
ocular surface and more inflammation. The first published reference to tear
osmolarity was in 1941, but not much, if anything, was published again until
1961.4 However, with the work of R. Linsy Farris, MD, and Jeffrey P.
Gilbard, MD, in the late 1970s, the topic really started gaining momentum.
They proposed that tear osmolarity was the gold standard for diagnosing dry
In its infancy, tear osmolarity required the use of laboratory
instruments and there were three or four different devices using different
methodologies (i.e., vapor pressure and freezing point depression) that
required high volumes of fluid (anywhere from 5 mL to 30 mL). Collecting
such an amount of fluid is difficult in normals, let alone in dry eye patients.
Additionally, because of the volumes required and the difficulty of obtaining
them in a glass capillary, the collection was frequently taken from both eyes
and pooled together, or in some cases taken from multiple eyes of
individuals and pooled together. Needless to say, tear osmolarity
measurement was not practical for use in the office. These roadblocks were
the reason for the paucity of information about sensitivity, specificity and
reproducibility—all of the things that you would like to know about in a
marker. Nonetheless, papers continued to point out that measuring the
osmolarity of the tear film was important and probably the best single test
for diagnosing dry eye disease.8–10
In 2008, the TearLab Osmolarity System (TearLab Corporation)
became available. This device requires the collection of just 50 nL of fluid
(the size of a period at the end of a sentence) from the inferior marginal tear
strip with a single-use, individually packaged, sterile, polycarbonate
microchip. Not only is the collection very rapid, preventing evaporative loss
of tears, but the actual measurement occurs within three seconds and is
recorded when you rest the TearLab Osmolarity System Pen in a receiving
receptacle unit on the countertop. So now we have a measure that is suitable
for a medical office and can be done easily, even by individuals who do not
necessarily have medical training. The impetus behind the roundtable—and
this subsequent monograph summary—is the advent of this new in-office
technology. We will take a look at a variety of issues, including those that
had not really been asked before.
Michael A. Lemp, MD
Michael A. Lemp, MD: Tear osmolarity can be measured a number of
ways, including freezing point depression, vapor pressure and direct
electrical conductivity, which all require a lot of volume (0.8 µL–0.96 µL or
larger). Trying to collect large tear volumes often causes overstimulation of
the lacrimal gland (reflex tearing), which results in more diluted samples and
variable results.8,11 The TearLab Osmolarity System, which determines
osmolarity through the measurement of electrical impedance of tear samples,
requires about one-sixth to one-eighth of the volume required by other tear
osmolarity measuring devices. It also does not require collection with a glass
capillary tube and transfer to a measuring chamber, which results in
evaporative tear loss, so it is a lot easier for clinicians to use.
You all have access to the TearLab Osmolarity System. What about it was attractive to you in terms of your practice?
THE LURE OF TEAR OSMOLARITY
Jay S. Pepose, MD, PhD: I think one of the big problems that we face in
diagnosing dry eye is that we have too many tests that are often producing
conflicting results. Sometimes you’ll have patients who might have a rapid tear
breakup, no lissamine green staining and a low Schirmer’s test. You wind up
trying to differentially weight discordant signs with vague, non-specific
symptoms that also often poorly correlate, particularly for patients on the lower
end of the severity scale with mild dry eye disease. So when the TearLab
Osmolarity System became available, I think it gave us a unique marker that
was much more central to the true underlying disease pathogenesis and
correlated much closer to overall disease severity.
The impact of this new tool on dry eye diagnosis and management is
equivalent to that of glucose and hemoglobin A1c testing when they were
introduced for the diagnosis and management of diabetes, compared to
relying solely on signs and symptoms. Of course, as a clinician, you still have
to perform other dry eye tests, take a good history, examine and express the
meibomian glands and still be a cognitive physician in interpreting all of this
information. So that was what was attractive to me about the test. It is central
to all components and manifestations of dry eye, whether it be aqueous
deficiency or meibomian gland dysfunction or mixed disease.
Richard L. Lindstrom, MD: While I manage external disease, I have a
fairly heavy anterior segment surgical practice. I do perform Schirmer’s tests
and look at tear meniscus, tear film break-up time and vital staining, but I have
not found these to be very reliable. But the data I read on tear film osmolarity
suggests that it is a more reliable and specific test, and that is what motivated
me to evaluate it for our practice.
Eric D. Donnenfeld, MD: Despite the fact that ocular surface disease is the
single most common reason that patients come to see ophthalmologists and
optometrists, we still face significant challenges in the diagnosis of dry eye disease. It is one of the most underdiagnosed diseases and it impacts patient
quality of life, visual acuity and surgical outcome, so it affects almost
everything we do as ophthalmologists on a regular basis.
As a clinician, it makes sense to me to look at the actual etiology of what is
occurring on a pathological basis and to be able to measure it rather than to
look at the effect of the dry eye (i.e., staining or tear break-up time). And I
think that almost every clinician will find that the addition of tear osmolarity to
their practices will give them the ability to diagnose dry eye more easily and
quantitate the severity of the disease for developing rational treatment
protocols. Tear osmolarity is helpful in every aspect of the management of dry
Dr. Lemp: Osmolarity is a marker and has been shown to parallel disease
severity. It not only defines whether a patient has dry eye, but also how
severe. You can then use that as a marker over time to judge response to
Dr. Donnenfeld: That is exactly right. Osmolarity gives us a good gauge of
disease severity and gives me a marker of how aggressive I should be with
therapy because, as we are learning, dry eye is a progressive disease.
Christopher E. Starr, MD, FACS: I think the importance of osmolarity
can’t be overstated, especially in the context of the 2007 Report of the
International Dry Eye Workshop (DEWS), which I refer to as the Bible of dry eye.3 It is important to note that the definition of dry eye changed with the
DEWS report. It states that dry eye is a multifactorial disease of the tears and
ocular surface that results in symptoms of discomfort,6,12,13 visual disturbance,14-16 and tear film instability17-19 with potential damage to the ocular
surface. It is accompanied by increased osmolarity of the tear film20-23 and inflammation of the ocular surface.24,25 Given this definition, you technically
can’t have what we consider dry eye disease or ocular surface dysfunction
without hyperosmolarity. And that just speaks to the importance of the TearLab
Osmolarity System, because it is the first time that sophisticated laboratory science is now in our hands in a simple, repeatable, almost instantaneous point-
of-care test to diagnose hyperosmolarity.
Dr. Lemp: How do you incorporate this device into your practices and on
what patient types do you use it?
PUTTING IT INTO PRACTICE
Dr. Lindstrom: I have always been impressed by the impact of
undiagnosed dry eye on the outcome of anterior segment surgery, so this
has been a really good screening tool for me to identify undiagnosed dry
I am also using it in all of our patients who are wearing or being fit with
contact lenses. All of the doctors in our practice think it is an important test,
both for following patients in contact lenses but also for screening them prior to
I also have quite a few patients with dry eye disease, blepharitis and
meibomian gland dysfunction whom I am following long term. Interestingly
enough, some of them still have elevated tear film osmolarities in spite of the
therapies I am using, and I am getting a little more aggressive in those patients
and adding supplementary therapy. So I think tear film osmolarity is going to
help me quite a bit in managing my patients who have both evaporative and
aqueous deficient dry eye because it has given me insight into which therapies
are most effective.
I have not yet gotten to the point of screening every new patient, but I am
not far away from it, because so many of my patients have a history of dry
eye, some symptoms of dry eye or are contact lens wearers or surgical
Dr. Pepose: Tear osmolarity assessment is essential for patients undergoing
cataract, laser and refractive surgery. Refractive surgery presents a challenge to
the ocular surface and patients with dry eye lose the ability to respond to these
challenges. So we want to know ahead of time who is at high risk and who
needs to be pre-treated to optimize the tear film and ocular surface. It is also helpful in terms of narrowing the differential diagnosis for those symptomatic
patients and, as Dr. Donnenfeld alluded to, it serves as a useful tool in
designing a treatment plan.
DIAGNOSTIC TESTS FOR DRY EYE
The TearLab Osmolarity System (TearLab Corporation) is the only device
currently available that measures osmolarity, but other technologies and
methods have been around for years and detect dry eye by other means.
• TearLab Osmolarity System — measures tear osmolarity, or the
concentration of tears. The higher the osmolarity, the more likely the patient
has dry eye.
• LipiView Ocular Surface Interferometer (TearScience) — Operating on
the principle of broad-spectrum white light interferometry, it allows a
quantitative analysis of more than one billion data points of the interferometric
image of the tear film.
• Touch Tear MicroAssay System (Touch Scientific, Inc.) — an in vitro
diagnostic device that is used for the measurement of lactoferrin concentration
in human tears as an aid in the diagnosis of keratoconjunctivitis sicca and to
assess lacrimal gland function.
• RPS InflammaDry Detector (Rapid Pathogen Screening) — point-of-care
tests that detects for MMP-9, an inflammatory marker that has been shown to
be elevated in the tears of patients with dry eye disease.
• Corneal staining — (e.g., lissamine green, rose bengal, fluorescein)
determines the surface condition of eyes and the quality of tears by staining loss
of the mucin layer, dead or degenerated epithelial cells.
• Schirmer’s test — can be done without a local anesthetic (Schirmer’s I test)
or with (Schirmer’s II test). For both procedures, paper strips are placed in each
eye for approximately five minutes to assess aqueous production.
• Tear film break-up time — measures the interval between the last complete
blink and the breakup of the tear film.
• Meibography — examines meibomian gland function.
• Ocular Surface Disease Index (OSDI) — a scientifically validated 20-
question self-diagnostic survey that produces a score based on commonly recognized symptoms and their severity and helps patients communicate more
effectively with their doctors.
• Fluorophotometry — determines tear turnover rate, tear volume and tear
flow by measuring the decay of fluorescein in the tear film.
Marguerite B. McDonald, MD, FACS: If the patient had no external
disease issues or complaints, I usually had my technicians get the intraocular
pressure of most patients before I saw them, but once tear osmolarity testing
became available, we were not able to get a reading once a patient had
ophthaine and fluorescein in their eyes. Now I have a sign posted to remind
technicians to get tear osmolarity before anything else on any patient who is 40
years old or older; says they have dry eyes or makes a complaint about ocular
surface discomfort; has been diagnosed with ocular surface disease in the past
by us or other doctors; or is being worked up for any type of ophthalmic
Dr. Lemp: In visiting offices around the country, I have found that when you
are trying to implement a new technician-operated technology such as this, one
of the biggest obstacles can be where you place it. It only takes a technician a
few minutes to perform, but if you have to stand in line to get to the machine, it
can be a bit of a barrier. Are there any comments on that in terms of
implementing it in your practice?
Dr. McDonald: Recently, I was at one end of our long and narrow office
when I realized that I would be sharing the osmolarity unit that day with
another cornea specialist who was seeing patients at the other end of the office.
I moved my patients and technicians to the other end so that we can share our
unit until we get a second one for that office. There was no way that I could
have tested osmolarity that day if the unit were located 100 feet away.
Dr. Lemp: A recent study using the TearLab Osmolarity System across
11 sites in Europe and the United States found that about 70 percent of the time in moderate to severe dry eye, you will have both readings in the abnormal range, but about 30 percent of the time, one
of them may get down into the normal range.10 Because of the inherent
instability of the tear film in dry eye disease, the osmolarity of both eyes
must be tested using the higher of the two results to determine the diagnosis
and the disease severity. Only disease drives osmolarity up, and if it’s
driven down in the other eye, that can be a compensatory mechanism that
you see, which is transitory and happens unilaterally, we find from
research.10 That’s true both in one eye to the other, inter-eye variability
and variability over time in the same eye.
We looked at the variability for all of the other objective tests that are
commonly used for dry eye over a three-month period, and tear film
osmolarity is less variable than the others (see Table 1).10 However,
variability confirms, rather than confounds the diagnosis of dry eye. Have
you dealt with this as an issue?
VARIABILITY: AN UNAVOIDABLE TRUTH
Dr. Lindstrom: I have only been using this instrument routinely for about
three months now, and I am finding some variability in the readings, but I
interpret it as a sign of an unstable tear film either from evaporative or aqueous
deficient dry eye. There certainly is a number that is suggestive of dry eye, so I
look for a high tear film osmolarity, but also for variability in the readings and
also for asymmetry between the two eyes. All patients with ocular surface
disease do have compensatory mechanisms, but in certain environments, these
are overwhelmed and other times they are over- or under-responding. So the
variability in tear film osmolarity really makes sense to me as an important sign
of a patient with dry eye disease.
Dr. Starr: Certainly the moderate to severe patients tend to have more
variability than the normal patients, but if you look at the variability over time,
almost all of the measurements in severe patients will still be above our cutoff
of 308 mOsms/L.10 And so while the tear osmolarity might be 350 mOsms/L in
the higher of the two eyes at one visit and 320 mOsms/L the next time, over
time, these numbers will largely still be above that 308 mOsms/L cutoff, so
they are still hyperosmolar and still have dry eye.
Dr. Donnenfeld: We have found tear osmolarity to be sensitive to the
clinicians and technicians who are performing the testing, so I strongly
advocate that you have the same technician(s) performing tear osmolarity in
your office whenever possible because there is a learning curve and we find
that we get much more reproducible results when we have someone with
experience doing the testing.
Dr. Pepose: We have found the same thing, and I think a lot of it has to do
with not pulling on the lid and causing reflex tearing, which was the problem
with the initial testing units prior to the TearLab Osmolarity System. So I think
just collecting from the tear meniscus itself, without eliciting reflex tearing, is
important and not difficult to do with a little bit of practice.
Dr. Starr: I agree, anyone who can do a Schirmer’s test can certainly do this.
Tear osmolarity is much faster, more reliable and is easier to perform, but at the
same time, you want to be sure that we are not irritating the ocular surface, the
conjunctiva or the eyelid by poking or taking too long to get the measurement,
because you could very easily stimulate reflex tearing, which might lead to
erroneous data. But I would say that almost everybody in my office who has
used this device got quick and easy tests right off the bat.
Dr. Lemp: Too often, we hear clinicians say that they don’t need any
diagnostic devices for dry eye because they listen to symptoms. And if a patient
does not have any symptoms, then they are not going to open that box. Or, that they just listen to symptoms and judge severity on how much the patient
complains about symptoms. What is your response to this frequently expressed
THE ROLE OF SYMPTOMS
Dr. Donnenfeld: I think that is a fairly archaic approach to dry eye disease.
It is akin to saying that you don’t treat glaucoma until a patient notices a visual
field loss. We all know that the symptoms of dry eye disease are variable and
that often, patients have different experiences. If you have a disease that is
progressive (such as dry eye), then I think it behooves us as clinicians to treat
aggressively early on to prevent the disease from worsening.
Dr. Lindstrom: Symptoms are not a reliable indicator of dry eye and we all
know that there are highly symptomatic patients who do not have signs as well
as patients who have a lot of signs but no symptoms. And in the most stressful
environments, everyone will have dry eye, but some people will notice or
express the symptoms, and others will not.
I am finding that when I do the tear film osmolarity screening test, a patient
may not have come in with a chief complaint of dry, burning or irritated eyes,
but when I see the elevated tear film osmolarity and ask if they notice their
symptoms more in certain situations/environments (e.g., summer time, winter,
when outside bicycling, later in the day), I elicit symptoms that are totally
consistent with dry eye.
So I do not find the patient’s spontaneous description very reliable, which is
one of the reasons why I am thinking about screening all new patients with this
test. It is so simple, minimally invasive and inexpensive for a problem that is so
ubiquitous, routine use may make sense.
Dr. Pepose: I think the discordance between signs and symptoms is more
common in people with the mild to moderate forms of the disease. In healthy
individuals, homeostatic mechanisms are always at play in the human body,
including those that keep tear osmolarity within a normal range. But with
chronic dry eye disease, you may exhaust some of these compensatory mechanisms, and so what might have started out primarily as an aqueous
deficiency now quickly becomes a mixed disease of both evaporative and
aqueous components. So it will be good to identify the condition early on and
initiate treatment before you are no longer able to have these normal
Dr. Starr: We have known historically that symptoms do not always
correlate to the findings; this has been well established. Many practitioners still
solely think of dry eye symptoms as ocular irritation, dryness and a sandy
sensation, and overlook other key symptoms such as reduced visual quality,
acuity and visual fluctuations throughout the day. These are particularly
important in refractive cataract and laser vision correction patients.
Dr. Lemp: That is a great point. Also, not everyone may be aware of the fact
that the particular visual complaints of dry eye patients are not necessarily
picked up on a Snellen acuity chart because most of those complaints occur in
between blinks. The tear film breaks up rapidly and patients can frequently
blink and momentarily, get a clearer view of the chart and read it for us, but
then two to three seconds later, that image has broken up, so we need more
sophisticated ways of picking up on that kind of visual disability.
What do your patients think about tear osmolarity testing. How have they
THE PATIENT FACTOR
Dr. Lindstrom: I have not had a single patient complain about the test, in
terms of both the experience of having the test done or the cost. I explain to
them what we are looking for and that it is a very common disease that is
often missed. We have always been a high-tech, high-touch practice, and
when I incorporate these technologies, my patients are impressed that I
have instruments and use technology that the other doctors they have seen
do not have.
Dr. Lemp: So it is actually a kind of marketing tool for your practice.
Dr. Lindstrom: It has been for us. We get referrals from a very large group
of doctors, and it is kind of fun to dictate back that I thought the patient had
mild symptoms of meibomian gland dysfunction or a little tear film instability
and to include the tear film osmolarity readings that confirm my initial
diagnosis. The referring doctors love it too.
Dr. McDonald: My patients like having a number and for me, it is nice to be
able to say, “The last time your tear osmolarity measurement was X, and now it
is Y. It is lower because you have stayed on your regimen.” I think that sharing
tear osmolarity measurements with patients is truly playing a role in the
increased compliance I am seeing lately.
Dr. Pepose: I have found the same to be true. Patients are eager to find out
what their number is and to see how it has changed with therapy. They really
accept the test because it makes sense to them to have an objective marker.
Dr. Starr: I often equate it to the hemoglobin A1c measurement in diabetics,
which is a number that is linearly related to their blood sugar status over time.
These patients always know their most recent “number” and are proud when it
is low or lower. Dry eye patients view their osmolarity number similarly and
await the result with bated breath, hoping it is lower than before. And if it is
not, then we might add to or modify their treatment, but the patients are very
aware of their numbers, the progression of their disease and the effectiveness of
Dr. McDonald: That helps in cases where there is a big disconnect between
signs and symptoms. Once in a while, you find a patient with 4+ superficial
punctate keratopathy from dry eye syndrome, who has lost several lines of
vision, and for some reason is not complaining. You try to convince them they
have dry eye and put them on a topical immunomodulator and several other
adjunctive therapies, but they are not compliant because they do not believe
that they have dry eye. With the TearLab Osmolarity System, you have a number you can share with them. You can say, “Your score is 335 mOsms/L.
Normal is below 308 mOsms/L.” The number gives that occasional moderate
to severe dry eye patients with minimal symptoms a reason to listen to you.
Dr. Lemp: What impact does the use of a technology such as the TearLab
Osmolarity System have on your patient flow?
Dr. Lindstrom: We have delegated the ability to perform this test to certified
trained technicians when patients have certain signs and symptoms or on those
who are pre-surgical, are contact lens wearers or have an on-the-chart diagnosis
of dry eye or blepharitis/meibomian gland dysfunction, as well as those on
whom we have not yet performed the test.
And on return visits, when I want a follow-up reading to evaluate the impact
of my therapy or because I am uncertain, I will order it. So our technicians
perform this test early in the examination, prior to placement of fluorescein,
anesthetic or any other drops. I had been concerned that if we had used a
topical anesthetic in the eye to check pressures, it would render the readings
useless, but I am becoming more confident that you can still get a useful
reading if you wait 20 to 30 minutes after checking their pressures.
Dr. Lemp: A recent unpublished study looked at variable periods of time
after the instillation of a topical anesthetic and some fluorescein in the pupil.26 We did serial measurements of tear film osmolarity and found that
fluorescein and topical anesthetics destabilize the tear film, but that after
about 10 minutes, that destabilization effect seems to disappear. So we have
perhaps been overly cautious in saying we should wait two hours.
On the flip side, we know from other studies that certain artificial tears—particularly those with big polymer molecules that hold water and are highly
hygroscopic, like hyaluronic acid—can abnormally stabilize your tear film for
an hour and a half to two hours. So it is conceivable that a patient could get a
lower reading after having put a drop in his or her own eye.
Dr. Lindstrom: Occasionally, a technician will not think that a patient
meets the category that I wanted to test, so when they get to me, they have
already had their pressure taken. Then the question is whether I can send them
back for osmolarity testing and have it still be meaningful. But usually by the
time I am completing my exam, 30 minutes has elapsed, so I like that 10-
minute number a lot, compared to the alternative, which is to bring patient
back for another visit or keep them around for two hours.
Dr. Starr: In the age of osmolarity, I have abandoned Schirmer scores. A
Schirmer test takes at least 10 minutes to perform; you can do the osmolarity
test at least three or four times in that amount of time. So that is a huge
difference in shortening the flow and the amount of time the patient is in your
office. Schirmer’s tests are limited to aqueous deficiency states, whereas
osmolarity will be high in both aqueous deficiency and evaporative forms of
dry eye. And the icing on the cake is that it is reimbursable—twice even—if
you test both eyes, whereas the Schirmer’s test is not.
Dr. Lemp: In January 2011, the Centers for Medicare and Medicaid
Services (CMS) issued the code 83861 “Microfluidic analysis utilizing an
integrated collection and analysis device; tear osmolarity,” which pays
$23.58 per eye. However, 12 states fall below the national payment. TearLab
lists common issues with the new code on their website, www.tearlab.com,
and has a Reimbursement Support Center, which can also be accessed
through the website, to assist practices in dealing with any reimbursement
issues. The company’s website also provides a partial list of applicable
diagnostic codes for your reference.
What financial impact does technology such as the TearLab Osmolarity
System have on your practice?
Dr. McDonald: Improved quality of care was the only driver for our
incorporation of this technology into our practice. Having said that, the
financial impact has been positive. For the Hawaiian Eye 2011 meeting, I
was asked to cover this topic. I was fortunate enough to have Bruce Maller,
the prominent ophthalmic business consultant, share with me a financial
model for a comprehensive ophthalmology practice that would become a dry
eye center of excellence (or at least make it a focus of their practice).
With a reasonable amount of cost-efficient, mostly internal marketing, a
medium-sized practice should be able to attract 1,500 new dry eye patients
over the course of a year. Using conservative estimates for the number of
visits per year for these patients, the number of punctal plugs that would be
inserted, the number of related eye conditions that would be diagnosed and
the number of additional surgeries (cataract, glaucoma, etc) that would be
generated, there was a significant increase in the practice income (using
2011 national Medicare rates): $731, 650.
Expanding on Bruce’s model, if tear osmolarity testing were performed on
these 1,500 new dry eye patients during all four of their visits that year, the
net revenue would be $93,460 from the testing alone.
Dr. Lindstrom: We have a fairly large practice, and we did not incorporate
this technology from the perspective of enhancing revenues—at least from the
charge for the test. We were more driven from the perspective of enhancing the
quality of care and in a consultative practice, of differentiating our practice.
I would say that the financial benefit has been that our practice has another
(albeit relatively simple) impressive technology that our competitors do not
have. It is really helping us strengthen our image in the community, and we
have had both referring doctors and patients remark on that. In fact, I think
some of our referring doctors will probably also decide to acquire the
technology based on the fact that it has been helpful to us both in solving
problems about which they were uncertain.
Dr. Lemp: That is very good. I would like to get into one final issue with you all. TearLab technology requires a laboratory license to use it because of
the particular part of the FDA that governs tests that take samples out of the
body (Clinical Laboratory Improvement Act [CLIA]). The TearLab
Osmolarity System is regulated as Moderated Complex device under CLIA,
so all customers must have a Moderate Complex CLIA license. Was getting a
laboratory license a barrier to you or in any way difficult?
A NECESSARY EVIL
Dr. McDonald: TearLab has helped facilitate the process of becoming a
certified laboratory by offering the services of an outside company (COLA,
www.COLA.org) that makes obtaining a license quite easy, so it is really a
Dr. Pepose: We have obtained our laboratory license, and it was not at all
problematic. We had one of the doctors in the office become the laboratory
director, and they certify the technicians who will be performing the tests. We
have documentation that we are performing the tests properly, and it is pretty
I look at this as our first venture into the equivalent of what laboratory testing
is for internal medicine. It may behoove people to get licensed because there
may be tear immunoglobulin E (IgE) testing down the road, and other
laboratory tear tests that all have the same basic “lab in a chip” platform.
Dr. Lemp: As a matter of fact, IgE development is underway right now, so
this particular platform lends itself to multiple tests, and I think we can look
forward to this in the future.
Dr. Starr: My administrator is currently working on our CLIA license, so
I have been using the TearLab Osmolarity System for research purposes
under my Institutional Review Board (IRB).
Dr. Lemp: Does anyone have any other comments?
Dr. McDonald: I would advise doctors and their technicians to start
instructing patients to not instill eye drops two hours prior to their next visit
if at all possible, so that tear osmolarity testing can be performed. The
appointment desk can remind patients as well.
Dr. Lindstrom: Getting our practice going with this test has been a bit of a
process, but now there is a lot of momentum with our whole group. Our
doctors like it, our patients like it and our referring doctors like it. We only
have the technology in four of our 12 offices, and as word is getting out
regarding its value, the other offices are agitating that they want one as well.
Dr. Pepose: We are not only ocular surface disease specialists, but also
surgeons. I am not sure that all ophthalmic surgeons fully appreciate the
importance of having a good tear film for quality visual outcomes. The
demands for quality outcomes have increased dramatically as refractive
cataract and corneal surgery have seamlessly merged and now entered
As a corneal specialist, I can’t tell you how many patients come to me with
complaints that they relate to their refractive surgery, when the problem is not
the IOL or laser procedure, but the poor tear film, which is the first aspect of
the ocular surface that refracts light. Managing the dry eye and ocular surface
disease in these patients results in significant improvement of their symptoms,
better patient satisfaction and subsequently, happier clinicians. So we
routinely evaluate dry eye preoperatively, and it is probably the most
important evaluation that we can do to improve our outcomes with refractive
and cataract surgery.
Dr. Donnenfeld: I always view the opportunity to participate in new
technology as a way to improve patient care, and TearLab offers me a
technology that enables me to differentiate my practices from others in the
community, which patients recognize. When you can offer something that’s
distinctly different from other practices, patients perceive you as a more progressive practice, and that brings them back for other surgeries and leads to
Lastly, the TearLab Osmolarity System allows me to make the diagnosis of
dry eye more easily, which gives me more time to tell patients about their
disease process and about treatment options. Dry eye disease is something that
patients generally do not fully understand, so giving me that resource of more
time is probably the most precious aspect of TearLab.
Dr. Starr: I agree wholeheartedly with the previous comments, and my
parting thought will be somewhat philosophical. Before TearLab osmolarity,
we all became very astute at diagnosing what we believed to be dry eye based
on patient symptoms, subjective tests and slit lamp findings, and treated
patients accordingly. With TearLab, we now have an objective, highly sensitive
and specific marker of dry eye disease that does not always correlate with our
tried, but not always true, clinical assessments. When this happens, and it is not
infrequent, many clinicians—and in the beginning, I was guilty of this too—
will immediately blame the device, assuming it must be wrong.
With time, I have swallowed my humble pie and have rightly put my faith in
the osmolarity measurement, rather than an antiquated, clinically subjective
idea of dry eye disease. Remember, if the osmolarity is normal, it is not dry
eye. Period. If you are perplexed by an unexpected low osmolarity
measurement, then do your patient a favor and look for another diagnosis with
overlapping symptoms such as allergy, conjunctivochalasis, medicamentosa
Dr. Lemp: A recent study by my research group that will soon be in press
looked at a large group of people who had objective evidence of dry eye
disease. We found that only 70 percent of them were symptomatic. So much
for symptoms alone to make this diagnosis.
Dr. Pepose: I agree, and in terms of osmolarity testing, you can have a
patient who might be at the 308 mOsms/L “normal” threshold who still has dry
eye. These points have been picked to try to maximize the specificity and sensitivity of a test. But you could have a patient who started out at 280
mOsms/L and is now at a new 308 mOsms/L set point, and for them, that
relative shift is hyperosmolar. Serial testing is also very important in this
chronic, vacillating disease, and just as Dr. Starr said, you have to have
confidence in the instrument and the readout.
Finally, to elaborate on Dr. Donnenfeld’s comment, just as patients refer other
patients because they identify your practice as a dry eye center, we are finding
in my multi-specialty practice that there is enough interest from the retina
doctor and other subspecialists to learn about this technology. And just as we
send wet age-related macular patients to our retina colleagues, they are starting
to send patients with a diagnosis of dry eye to us when they want a dry eye
workup. So this technology really allows you to be even more of a subspecialist
and differentiate yourself from other doctors.
Dr. Lemp: Those are all wonderful points, and I think that this has been a
very fruitful discussion.
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