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Normal, abnormal tear osmolarity scores both aid diagnoses
"At Issue" asked a panel of experts: How do you use tear osmolarity testing in your practice?
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Dry eye can be subclassified as either aqueous deficient or evaporative, although it is now understood that abnormal osmolarity is a common pathway underlying the distinct etiologies.
As such, tear osmolarity testing is rapidly emerging as an additional tool to clinically evaluate patients. The test supplies an objective quantifiable score that clinicians can use for confirming the diagnosis and following patients for response to treatment over time.
Studies confirm that tear osmolarity measuring greater than 308 mOsm/mL indicates a loss of homeostasis in the tear, while a difference of 8 mOsm/mL between the two eyes suggests tear film instability. Higher scores are correlated with more severe dry eye disease. Many clinicians, therefore, find value in performing a test at the initial consultation to evaluate the health of the tear film. Serial testing over time indicates whether the assigned treatment course is having an effect.
“At Issue” asked several practicing optometrists how they are using this technology in their practices.
Contact lens intolerance unmasked
by Marc Bloomenstein, OD, FAAO
A 37-year-old woman presented for a contact lens evaluation. She had successfully been wearing contact lenses with a 2-week replacement schedule for more than 10 years and used a multipurpose solution for cleaning. However, she reported that her “contacts are not as comfortable as they used to be,” “My eyes itch more; I think my allergies are bothering me” and “I think it is time to get an update to my prescription because the vision just isn’t as good.” The patient was taking Claritin (loratadine, Bayer) and using Systane Ultra (polyethylene glycol 400 0.4% and propylene glycol 0.3%, Alcon) as needed for symptomatic relief.
At the time of examination, refraction measured 20/20 OD and 20/20–2 OS. Slit-lamp examination showed trace tarsal papillary response in the right eye greater than the left. There was trace injection and no staining of the cornea. The iris appeared round, the lens was clear, and the ocular nerve head, macula and retina were all normal in appearance. There was very trace staining under lissamine green. Tear osmolarity scores with the TearLab Osmolarity System (TearLab) were 322 mOsm/mL OD and 303 mOsm/mL OS. The inter-eye difference suggested an initial diagnosis of keratoconjunctivitis sicca and an underlying problem with the tear lens, as did the elevated reading in the right eye.
After discussing the osmolarity readings with the patient as well as the need to reestablish homeostasis in order to create a healthy tear lens, the decision was made to start treatment with Restasis (cyclosporine 0.05%, Allergan). I was not as concerned about the patient’s report of itch, although that could indicate a diagnosis of allergic conjunctivitis; no treatment was offered for allergies at that time. There was no change in her contact lenses
The patient returned in 4 weeks, reporting that her contacts “feel somewhat better,” she “has not noticed them as much” and “they don’t itch, either.” At this exam, her best-corrected visual acuity was 20/20 OD and 20/15 OS. Slit-lamp examination was within normal limits. Osmolarity measured 304 mOsm/mL OD and 285 mOsm/mL OS. The reduction in the osmolarity indicated that cyclosporine was helping to reduce the inflammation and increase the tear volume.
The patient returned 6 to 8 weeks later and stated, “No changes from last visit. Doing fine.” BCVA was 20/20 OD and OS. Slit lamp was normal; tear osmolarity tests were 288 mOsm/mL OD and 293 mOsm/mL OS.
It was determined by this course of treatment and follow-up that the patient had keratoconjunctivitis sicca. The response on serial osmolarity testing confirmed both the original suspicion of underlying dry eye, with a tear lens that was unstable and unhealthy leading to contact lens intolerance, as well as the positive response to treatment. The patient was instructed to continue current management with cyclosporine therapy and return in another 8 months for a comprehensive examination.
- For more information:
- Marc Bloomenstein OD, FAAO, practices at the Schwartz Laser Eye Center in Scottsdale, Ariz., and is a Primary Care Optometry News Editorial Board member. He can be reached at mbloomenstein@gmail.com.
Disclosure: Bloomenstein is a consultant to Alcon, Allergan, Bausch + Lomb, Lunovus, OcuSoft, Shire and TearLab.
Refractive surgery delayed due to test results
by David I. Geffen, OD
A 37-year-old female was referred to me for a refractive surgery consultation. At the initial visit, her refraction measured –4.50 –0.50 × 28 20/20+ OD and –4.75 –1.25 × 172 20/20+ OS. Slit-lamp examination showed some minor stippling in both eyes, and evidence suggested meibomian gland dysfunction (MGD). As a result, tear osmolarity testing was performed, and osmolarity scores were 310 mOsm/mL OD and 315 mOsm/mL OS.
Osmolarity higher than 308 mOsm/mL indicates mild dry eye disease, although it may not be diagnostic on its own. Thus, due to the presence of irregular osmolarity and signs of dry eye disease, a decision was made to delay surgery and treat the dry eye.
A treatment plan was designed that included a Bruder mask and use of Restasis twice daily. The patient was also advised to begin using omega-3 supplementation. We recommend 2,000 per day and use a product called Ultra Dry Eye TG (OcuSci), which is one of the most potent omega-3s available. The patient was offered education on artificial tears and how they may complement the treatment protocol.
At a follow-up visit 4 weeks later, tear osmolarity scores were 305 mOsm/mL OU. There was no staining, and meibomian gland function had improved since the previous examination. The patient reported that her eyes felt more comfortable and that she did not even realize that she was previously uncomfortable. The patient underwent refractive surgery the following week and had an excellent outcome.
We cannot know for certain if her dry eye, left untreated, would have resulted in a negative outcome; however, such a scenario is likely, as even mild dry eye can slow down the healing process and cause ocular discomfort and other symptoms. In this case, the use of serial osmolarity testing indicated that the treatment plan was effective in resolving the underlying pathophysiology. This case also demonstrates that signs and symptoms do not always correlate, as there was improvement in osmolarity scores, and the patient reported feeling relief for a problem she did not even know she had.
- For more information:
- David I. Geffen, OD, is a partner with Gordon Schanzlin New Vision Institute-TLC in San Diego. He can be reached at dig2020@aol.com.
Disclosure: Geffen has received honorarium as a speaker and/or consultant for Abbott Medical Optics, Alcon, Allergan, Annidis, Bausch + Lomb, Nicox, TearLab and Vmax.
Healthy tear osmolarity score aids diagnosis
by Whitney Hauser, OD
Sometimes a tear osmolarity reading indicating a healthy tear film can be just as useful as one indicating a problem.
A 50-year-old man was referred to my clinic for evaluation of dry eye symptoms of about 2 years duration. He had previously received intense pulsed light therapy, which he reported had no effect on his symptoms.
At the time of the visit, the patient complained of irritation, redness and watery eyes. In particular, he said, the watery eyes drove him crazy all day and impeded his ability to sustain computer use for long periods of time. A series of diagnostic tests were performed, including InflammaDry (Rapid Pathogen Screening), dynamic meibography imaging with LipiView (TearScience) and tear osmolarity testing. A Zone-Quick test (Menicon) was completely saturated and was greater than 30 mm, which more or less ruled out aqueous deficiency. Osmolarity was 300 mOsm/mL in one eye and 302 mOsm/mL in the other eye; the normal finding was interesting, given the reported symptoms. The LipiView was slightly depressed, measuring about 70 nm of lipid layer thickness. The meibography looked normal, and the meibomian glands appeared healthy.
Slit-lamp examination revealed telangiectasia and inflammation at the lid margin. Also readily apparent was a Demodex infection. We decided to treat with BlephEx (RySurg), which mechanically débrides the lid margin, followed by Cliradex (Bio-Tissue) twice daily for 1 month, which creates a hostile environment for the Demodex.
Demodecosis is a chronic and recurring condition among many patient populations, including those with rosacea and the elderly. Therefore, no treatment will completely eliminate the Demodex, and maintenance is required for success.
At a follow-up examination at the conclusion of treatment, there was complete resolution of the patient’s symptoms. Continued lower lid thickness suggested ongoing MGD, which we are continuing to treat.
In this case, the normal tear osmolarity test was a big clue that this may not be true dry eye disease. Before I even entered the exam room, the test results indicated a healthy tear film, so I sought to find out if there was another cause. In this case, tear osmolarity testing removed the red herring — and made the elephant in the room easier to see.
- For more information:
- Whitney Hauser, OD, is a clinical development consultant, TearWell Advanced Dry Eye Treatment Center, and an assistant professor at Southern College of Optometry, Memphis. She can be reached at whitneyhauser@sco.edu.
Disclosure: Hauser is an advisory board member for 1-800-DOCTORS, Paragon BioTek, ScienceBased Health and TearLab; a speaker for BioTissue, Lumenis and NovaBay; a consultant for Allergan; a speaker/consultant for Akorn, Shire and TearScience; and founder/senior consultant for Signal Ophthalmic Consulting.
Tear osmolarity helps narrow the differential
by Walter O. Whitley, OD, MBA, FAAO
Tear osmolarity can be extremely useful for determining the appropriate treatment course and, in some cases, may redirect attention to the true cause of ocular surface discomfort.
A 72-year-old African-American woman was referred to my clinic for a cataract evaluation. She complained of blurry vision on presentation and reported a dry sensation in the left eye more than the right. She reported using artificial tears as needed. Medical history included allergies, acid reflux and hypertension.
Ocular examination revealed significant cataract. The patient underwent uneventful cataract surgery but reported continued dryness postoperatively, greater in the left eye than the right. Once the postoperative topical therapy regimen, consisting of steroids and nonsteroidals, was stopped, the patient was directed to switch to preservative-free artificial tears. Therapy with Restasis was also initiated due to complaints of chronic irritation, 1+ superficial punctate keratitis (SPK) in the right eye, 2+ SPK in the left eye and tearing. The patient was educated on the use of cyclosporine and expectations over time with increased tear production. She was scheduled to follow up in 3 to 4 months.
During a follow-up visit 4 months later, the patient still complained of symptoms in her left eye, including foreign body sensation and chronic tearing. We had just recently integrated tear osmolarity testing into the practice, and that was performed. The left eye measured 298 mOsm/mL and the right eye measured 301 mOsm/mL. The normal readings suggested a different cause for the symptoms, which were further evaluated.
Considerations for ocular surface discomfort with a normal osmolarity reading may include pterygium, conjunctivochalasis, mild allergic conjunctivitis and epithelial basement membrane dystrophy. Upon further evaluation under fluorescein and lissamine green, the patient displayed mild to moderate conjunctivochalasis, which was previously and is often easily overlooked. Although the etiology remains unclear, some theories for its development include normal aging, eye rubbing, lid position abnormalities and chronic ocular irritation that degrades Tenon’s capsule, which results in poor adherence of the conjunctiva to the underlying ocular surface.
Providers, including myself, often diagnose patients with dry eye disease without considering all potential causes for discomfort. The unanswered question is: Which came first, the ocular irritation and inflammation leading to the breakdown in Tenon’s capsule or the delayed tear clearance due to the natural aging process? Either way, tear osmolarity was helpful in providing objective data to allow me to hone in on my diagnosis.
The patient was scheduled for a conjunctival resection with one of our surgeons. After the excess conjunctiva was removed, the patient reported no symptoms.
- For more information:
- Walter O. Whitley, OD, MBA, FAAO, is director of optometric services, Virginia Eye Consultants, Norfolk, Va. He can be reached at wwhitley@vec2020.com.
Disclosure: Whitley reported that he has received consulting fees from TearLab Corp.