September 2012

 

CORNEA

 

Device focus

New devices for ocular surface disease


by Michelle Dalton EyeWorld Contributing Writer

   

From inflammatory markers to plugged meibomian glands, newer tests are helping clinicians diagnose ocular surface disease issues less invasively

Editors' note: This article discusses diagnostic tests that have not yet been approved in the U.S.

inferior lid meibomian gland

An example of how to probe the inferior lid meibomian gland Source: Steven L. Maskin, M.D.

The Maskin Meibomian Gland Expressor The Maskin Meibomian Gland Expressor Source: Rhein Medical

Within the past 5 years, researchers have directed a considerable amount of time to understanding ocular surface disorders (OSD) and how to better diagnose and treat those disorders. "It's a really exciting time for dry eye," said Christopher E. Starr, M.D., assistant professor of ophthalmology; director, Refractive Surgery Service; and director, Cornea, Cataract, and Refractive Surgery Fellowship, Weill Cornell Medical College, New York. "We now have a firm understanding of the underlying etiology, and we know inflammation plays an important role in ocular surface disorders."

Exactly, said Parag A. Majmudar, M.D., associate professor of ophthalmology, Rush University Medical Center, Chicago, and in private practice, Chicago Cornea Consultants. "Clinicians in general are more aware of the issue of dry eye, and technology and pharmacology are advancing our knowledge base quickly," he said. "We've got a greater understanding of visual outcomes post-surgery and how the surface affects that. We're doing so much premium surgery, we want to be able to provide the best outcomes for our patients, and that's all coming back to the roots of OSD."

After treating dry eye for more than 20 years, Steven L. Maskin, M.D., founder, Focus on Females Education Foundation, and Dry Eye and Cornea Treatment Center, Tampa, Fla., said he's thrilled about the attention now being directed to MGD, "the most common cause of dry eye and the most challenging to treat." The past 5 years have created "a transformation in our ability to control MGD and dry eye," Dr. Maskin said. "The meibomian glands are a barometer of not just the health of the ocular surface but systemic diseases, too." These include allergies, sleep deprivation, autoimmune disorders, and even upper respiratory infections.

Dry eye tools

"While other specialties have had objective, non-invasive tools to diagnose various conditions, we in the dry eye realm haven't," Dr. Starr said. "The Dry Eye WorkShop report in 2007 changed the definition of dry eye to include both inflammation and hyperosmolarity of the tear film." As a result, clinicians are beginning to concentrate on the true pathogenesis of OSD and are appropriately tailoring their interventions at treating the disease rather than simply the symptoms with artificial tears and lubricants, Dr. Starr said. Dr. Majmudar said a recent study he was involved with found the incidence of routine dry eye in patients scheduled to undergo cataract surgery was around 66%. "It's a huge issue; a lot of surgery causes temporary dry eye, but this older population is at a higher risk simply because dry eye tends to be more prevalent in older people, post-menopausal women in particular," he said. While there's "no way" to look at a patient and determine the tear osmolarity, TearLab's Osmolarity System (TearLab, San Diego) "quickly and easily determines the osmolarity content," he said. Much like intraocular pressure in glaucoma, a patient's osmolarity may fluctuate throughout the day, so it's imperative to take more than one reading, Dr. Starr added. "It's a good way to stratify patients based on the results," Dr. Majmudar said, adding he has little firsthand experience with the device. "Tear osmolarity can be useful if you're not certain if the patient has dry eye," Dr. Maskin said. "Its use is more limited once the diagnosis is confirmed because it doesn't guide you toward which type of dry eye [aqueous-deficient or evaporative] the patient has."

In general, an osmolarity reading of 308 mOsms/L or higher indicates the presence of dry eye. And that in and of itself is invaluable in helping with patient compliance, Dr. Starr said.

"Patients with other medical conditions tend to be highly vested in their 'numbers'blood sugar and hemoglobin A1c, blood pressure, cholesterol, etc. tear osmolarity has become another important number," he said, and people want their numbers to fall back into a "normal" range while being treated. (Ironically, Schirmer's tests also use numbers that are easy to understand, but they never caught on with patients or doctors in this same manner, Dr. Starr said.) InflammaDry (Rapid Pathogen Screening [RPS], Sarasota, Fla.) evaluates a specific inflammatory markermatrix metalloproteinase-9 (MMP-9)known to be elevated in people with dry eye. "InflammaDry is promising because it can help us diagnose before someone becomes symptomatic. Studies have shown earlier diagnosis and treatment is an important factor in preventing progression," Dr. Majmudar said. The device is currently in clinical trials in the U.S., but has been granted the CE mark.

Meibomian gland

Obstructed meibomian glands are a leading cause of evaporative dry eye, and the Maskin Probes (Rhein Medical, St. Petersburg, Fla.) can establish and provide physical proof of patency; once those glands are cleared, "it's our task to protect the gland and its functional state," Dr. Maskin said. His Maskin Meibum Expressor (Rhein Medical) includes diamond knurling with double rollers to rapidly express the stagnant oils after probing. "If you treat with a probe and open up the glands, treat any comorbid disease that may be present, patients may go more than a year without needing their glands probed again," he said. "But if the patient returns 2-3 months later, invariably it's a comorbid local, regional, or systemic disease that has acted up, exerting an adverse impact on the meibomian glands."

He also likes the LipiFlow System (TearScience, Morrisville, N.C.), which first analyzes the tear film quality (through the LipiView); the LipiFlow slowly heats the glands from the conjunctival side in order to express them. LipiView analyzes the lipid component in tears; the more colors present, the healthier the tear film.

"It raises the temperature, which makes the oils easier to express after probing," Dr. Maskin said.

Dr. Majmudar believes the LipiFlow "expresses better than anything else" he's tried, and he prefers to use it in cases of evaporative dry eye with subsequent blepharitis or MGD. Pricing, however, may be an issue, as the system is not currently reimbursable, Dr. Starr said. For some patients with moderate to severe MGD, however, "spending $2,000 a year to not have to massage and heat their lids daily might be worth it."

Down the road

Dr. Starr said Bascom Palmer is working on an ultrahigh resolution optical coherence topographer that will be capable of imaging the precorneal tear film and the integrity of the corneal epithelium; he also believes specialized topographers that can capture the quality of the interblink tear film over time are promising. Eye fact

"Those are providing a very sophisticated way of measuring tear breakup timesa quantifiable, reproducible, objective number in a non-invasive manner that is preferable to using fluorescein dye," he said.

Dr. Majmudar said the OQAS (Visiometrics, Terrassa, Spain) detects the optical quality of the eye "and converts the images into a metric that's quantifiable. It may hold promise for dry eye as well."

Dr. Maskin is currently using intraductal microtubes (Rhein Medical) that can be inserted directly into the meibomian glands as drug delivery devices.

"The tests that are in development are easy to use and non-invasive," Dr. Starr said. "Welcome to the modern era of dry eye diagnostics."

Editors' note: Dr. Majmudar has financial interests with RPS, SARcode Bioscience (Brisbane, Calif.), and TearScience. Dr. Maskin has financial interests related to pending patents on meibomian gland probing and related diagnostic and treatment apparatus, and a royalty interest in the Maskin Meibum Expressor. Dr. Starr has financial interests with Allergan (Irvine, Calif.), Bausch + Lomb (Rochester, N.Y.), Merck (Whitehouse Station, N.J.), and RPS.

Contact information

Majmudar: 847-275-6174, pamajmudar@yahoo.com
Maskin: 813-875-0000, drmaskin@tampabay.rr.com
Starr: 646-962-3370, cestarr@med.cornell.edu

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