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Device measures lipid levels in tear film to track meibomian gland dysfunction
Imaging system helps physicians monitor MGD progression, while a related platform applies heat to stimulate meibomian gland secretions.
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A novel ocular surface imaging system enables keen surveillance of a subtle pathologic cascade related to meibomian gland dysfunction and dry eye disease, a physician said.
Richard S. Davidson, MD, outlined features of the LipiView Ocular Surface Interferometer (TearScience) during Cornea Subspecialty Day preceding the American Society of Cataract and Refractive Surgery annual meeting.
The LipiView Ocular Surface Interferometer measures tear film thickness and quantifies lipid levels in the tear film, key indicators of tear film health and stability.
Non-obvious meibomian gland dysfunction (MGD) may portend the development of manifest MGD, Davidson said.
“Not all MGD is obvious,” he said. “In fact, non-obvious MGD is quite common.”
Davidson cited a study in which 48% of patients had non-obvious MGD.
“Meibomian gland dysfunction may well be the leading cause of dry eye disease throughout the world,” Davidson said, quoting the International Workshop on Meibomian Gland Dysfunction executive summary published in Investigative Ophthalmology and Visual Science in 2011.
Precise measurement, data recall
Decreased lipids levels in the tear film spur evaporation of meibomian secretions, Davidson said.
“We get a decrease in the secretions. As a result of not having as much lipid in the tear film, evaporation increases anywhere between 4% and 16%,” he said. “We also get a decrease in aqueous layer thickness, an unstable tear film, and our patients come in with symptoms.”
Gland expression may be helpful in analyzing secretions.
“It’s important that when we evaluate patients for dry eye, we try to express the glands visually. A gland may look normal initially but when you express some of the meibum, you see that it is actually quite abnormal,” he said.
The LipiView Ocular Surface Interferometer enables precise measurement of tear film thickness and quantifies lipid levels. Measurement takes about 20 seconds per eye.
“It’s non-contact — very easy to sit at the machine and blink naturally,” Davidson said.
The device calculates and stores about 1 billion data points.
“Results are displayed on [a] printout, and you can clearly quantify the lipid layer and follow it with the patient,” he said. “We show the patient. ‘This is your lipid level today.’ They come back in 4 weeks and you re-test them and you can follow that progression.”
Adjunctive treatment
Conventional treatments such as warm compresses, eyelid scrubs and gland expression are difficult for patients to perform at home, Davidson said.
“When it comes to treatment, there are a lot of at-home treatments done,” he said. “Warm compresses are very difficult for patients to do. There are challenges to compliance. It’s very difficult to keep the compress warm enough for it to give a treatment effect. We give patients lid scrubs and massage the lashes to try to work the meibum out of the glands. But, again, all of these things are difficult to do at home.”
Furthermore, external heat is insufficient for treatment but excessive heat can damage the cornea, Davidson said.
The LipiView Ocular Surface Interferometer can be used in combination with the LipiFlow treatment for MGD. LipiFlow involves the application of heat to the inner eyelids, liquifies meibomian gland contents and spurs the release of meibomian secretions, he said.
“It takes about 12 minutes per eye,” Davidson said. “Heat is applied from these little suction cup devices, if you picture it, kind of massaging the lids. What happens is, it massages the meibomian glands from posterior to anterior, so it literally evacuates the entire gland.”
The LipiView Ocular Surface Interferometer, however, may be ineffective and cost prohibitive for some patients, Davidson said.
“There are still going to be a subset of patients who get no therapeutic benefit despite this special treatment. But the cost may be the biggest barrier for some patients because as of yet, we do not have any way to bill for this service,” he said. – by Matt Hasson
Reference:
- Nichols KK, Foulks GN, Bron AJ, et al. The International Workshop on Meibomian Gland Dysfunction: Executive summary. Invest Ophthalmol Vis Sci. 2011;52(4):1922-1929.
For more information:
- Richard S. Davidson, MD, can be reached at University of Colorado, School of Medicine, 1675 N. Aurora Court, MS F731, Aurora, CO 80045; 720-848-2500; fax: 720-848-5014; email: richard.davidson@ucdenver.edu.
- Disclosure: Davidson has no relevant financial disclosures.