EyeWorld Asia-Pacific June 2012 Issue

42 EWAP CORNEA June 2012 Diagnosing dry eye by Jena Passut EyeWorld Staff Writer Latest tools show promise for identifying dry eye and meibomian gland disease A case of dry eye disease, however mild, can wreak havoc on a surgical or treatment outcome. Inventors and companies are continuing to establish ways for clinicians to pre-operatively diagnose the pervasive disorder, which was defined by the Dry Eye Workshop Study Group (DEWS) in 2007 as a multifactorial disease of the ocular surface that includes an element of inflammation and is accompanied by increased osmolarity. Practitioners now are looking beyond clinical presentations such as Schirmer’s test, tear break-up times, or conjunctival/ corneal staining to biomechanical markers to diagnose ocular surface dysfunctions. Testing for MMP-9 The RPS InflammaDry Detector (Rapid Pathogen Screening, Sarasota, Fla., USA) is a rapid in- office test that detects elevated levels of matrix metalloproteinase-9 (MMP-9), an inflammatory marker. The device, which was recently launched in Europe and Asia and was granted a Medical Device License by Health Canada, delivers results taken from a small sample of human tears in 10 minutes. RPS noted the device has a clinical sensitivity of 85% and a specificity of 94%. “These are enzymes that are produced by stressed epithelial cells on the ocular surface,” said Terrence O’Brien, MD , professor of ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Fla., USA, who spoke about the test at the 2012 Hawaiian Eye meeting in Maui. “[The test is] easy to use and gives an immediate result, and we can incorporate this into our clinical practices in order to make a diagnosis and, more importantly, to institute effective treatments, especially treatments that would be aimed at reducing inflammation on the ocular surface.” Dr. O’Brien said he expects the device to become commercially available in the U.S. in early spring. Eric D. Donnenfeld, MD , co-chairman, Cornea, Nassau University Medical Center, East Meadow, NY, USA, called MMP-9 testing “exceptionally interesting”. “I think it’s going to change the way dry eye is managed,” he said. “Dry eye is the most difficult diagnosis to make clinically because every patient is so variable. Some patients can be extremely symptomatic, some not. The future is going to be using point-of-care tests in your office.” In the meantime Until an MMP-9 device is commercially available, osmolarity testing with the TearLab Osmolarity System (TearLab Corp., San Diego, Calif., USA) is readily available to test for subclinical dry eye. Osmolarity is a good dry eye marker, but it won’t tell a clinician what type of dry eye the patient has, Dr. Donnenfeld noted. “Tear film osmolarity has a good linear correlation with severity, as has been shown now in several studies,” Dr. O’Brien said. An irregular topography reading also points to dry eye and is a key test, Dr. Donnenfeld said. “When you see drop out on a topography, it means that the tear film has been disrupted,” he explained. Looking at the lipid layer Donald Smallman, MD , adjunct assistant professor, Queens University, Kingston, Ontario, Canada, and medical director, Kingston Eye Institute, has established a dry eye clinic in his practice. There, each patient fills out a screening questionnaire. “Because dry eye is such a common issue that plays a role in other eye diseases, many of our patients coming in for other issues will also have dry eye as a feature of their complaints,” Dr. Smallman said. If a slit lamp examination with dilating eye drops confirms suspicion of dry eye, Dr. Smallman brings patients back another day to be examined with the LipiView OSI (TearScience, Morrisville, NC, USA). The LipiView uses spectral interferometry, a spatially modulated light source that allows removal of unwanted background images and stray light, to analyze the patient’s lipid layer of tear film, as well as his or her blinking. “It gives a lot of information above and beyond just the lipid layer of the tears,” Dr. Smallman said. “That’s very important because it allows us to determine if a patient is suffering from evaporative dry eye because the absence or low levels of lipids in the tear film is associated with certain types of dry eye problems. It also allows us to target certain treatments to the meibomian glands specifically, as opposed to providing drops or supplements that will restore the aqueous layer. I feel like this is going to be a real boon for dry eye assessment.” The LipiView, which is attached to a LipiFlow treatment system for meibomian gland dysfunction (MGD), is able to differentiate between patients who have MGD and evaporative dry eye versus patients who have aqueous tear deficiency but healthy lipid layers, Dr. Smallman said. “It counts the number of blinks and measures the eyelid excursion for each blink, and you can very clearly diagnose partial, incomplete, or non-blinkers,” he said. “This is the first time I have seen any device that has been able to do this, and it’s been very surprising to me how many of my dry eye patients are partial or incomplete blinkers on top of the fact that they may have aqueous tear deficiency or MGD. If their lids are not closing all the way when they blink, they get worse symptoms.” In the pipeline Currently, OPIA Technologies (Paris) is developing a device called the EyePrim that takes impressions of the conjunctiva to help diagnose ocular surface disorders. The technique was recommended by the Tear Film & Ocular Surface Society in the 2007 DEWS report, the company said. Originally, inventor Christophe Baudouin, MD , professor and chair of ophthalmology, Quinze-Vingts Hospital, Paris, France, was testing the idea of lifting cells from the conjunctival impressions to diagnose ocular surface disorders. “In many cases, we would not get enough cells, or the cells would be destroyed and it was impossible to make a proper diagnosis,” explained Pierre Roy , OPIA’s CEO, an engineer who worked on the EyePrim’s more advanced collection platform. “The next big step is to work on biomarker identification coupled with this system.” Mr. Roy said the device is about to begin clinical trials in Europe and the U.S. “Several point-of-care tests are under development and will be released in 2012,” he said. EWAP Editors’ note: Dr. Donnenfeld has financial interests with Abbott Medical Optics (Santa Ana, Calif., USA). Dr. O’Brien is an ad-hoc, non-salaried consultant for Alcon (Fort Worth, Texas, USA/Hünenberg, Switzerland), Allergan (Irvine, Calif., USA), and Bausch + Lomb (Rochester, NY, USA). Mr. Roy is CEO of OPIA Technologies. Dr. Smallman has no financial interests related to this article. Contact information Donnenfeld: +1-516-446-3525, eddoph@aol.com O’Brien: +1-561-515-1544, tobrien@med.miami.edu Roy: +33(0)153462682, pierre.roy@opiatech.com Smallman: +1-613-546-1858, smallman@kingstoneyeinstitute.com Rainbow colors in the tear film indicate that it is rich with lipids that arerequired to keep the aqueous portion of the tears from evaporating too quickly Source: TearScience