Basic diagnostic steps can

Ruling in dry eye and ruling out other OSDs

Basic steps can help in diagnosis of DED. Roibeard Ó hÉineacháin reports

Incorporating the current guidelines from the Tear Film Ocular Surface Society’s 2017 dry eye workshop report (TFOS DEWS II) for dry eye disease (DED) diagnosis into one’s daily surgical practice does not require special expertise in ocular surface disease or the purchase of new expensive equipment, said Carina Koppen MD, PhD, University of Antwerp, Belgium.

“Actually, the scheme includes a lot of tests that you are already familiar with, and with a bit of organisation it’s very possible to include these tests in the routine of your daily workflow,” Dr Koppen told the 25th ESCRS Winter Meeting.

The guidelines suggest starting with a series of triaging questions to help rule in dry eye and rule out other ocular surface diseases. They include questions regarding not only the typical DED symptoms of discomfort and their triggering factors, but also questions regarding visual acuity and fluctuating vision. Also important is a risk factor analysis, to obtain a fuller picture of the patient’s overall ocular and systemic health, with questions regarding smoking, medications and contact lens wear.

Dr Koppen noted that the initial parts of the investigation can be greatly facilitated by the use of questionnaires, such as the Ocular Surface Disease Index and SANDE questionnaires. They have the advantage that patients can fill them out in the waiting room, reducing chair time.

SLIT-LAMP EXAMINATION The next step in the TFOS DEWS II scheme is a systematic slit-lamp examination of the ocular surface, including the eyelids,

lashes and margins and the lower and debate. The tests have high specificity (78upper conjunctiva. Features to look for to-99%) but a more variable sensitivity include conjunctival folds suggestive of dry (48-to-95%). eye disease and a frothy aspect of the tears “The main problem is that values of such as occur in the presence of meibomian osmolarity fluctuate, so it is advised to gland disease. at least test both eyes. The test would “You might miss cicatrising conjunctivitis probably be more sensitive if you do several or superior limbic keratoconjunctivitis if tests per eye but each chip costs money so you don’t examine the eye in the upward the test becomes prohibitively expensive if and downward gaze, and epithelial you’re going to test both eyes three times,” dystrophy, which is actually not so Dr Koppen said. rare if you look for it,” she said. Once it has been ascertained Following this examination, on the basis of these tests the clinician needs to that a patient has dry eye determine tear break-up disease, the next step is to time (TBUT) by instilling classify the condition as a drop of fluorescein. A evaporative or aqueous TBUT of less than 10 seconds deficient dry eye. Changes in is suggestive of tear film the tear film lipid layer and the instability, a TBUT of less than meibomian glands are suggestive five seconds is the signature of Carina Koppen MD, PhD of evaporative dry eye, while definitive DED. The residual reductions in the tear meniscus fluorescein stains areas of epithelial damage height indicate aqueous deficient dry eye, and erosions. Dr Koppen said. “As clinicians we should not forget to “Actually, it is not an either/or situation. systematically examine the eyelid margins Once the patient gets trapped in a vicious and the orifices of the meibomian gland circle of dry eye disease then both types will and to squeeze the glands to test their be present in the same patient at a certain functionality,” she added. point in time,” she added. Dr Koppen added that multi-functional MEASUREMENT devices are becoming available for OF TEAR OSMOLARITY Osmolarity is another parameter included in the TFOS DEWS II guidelines. Dr Koppen noted that hyperosmolarity is a hallmark sign of DED. Maximum osmolarity greater than 308mOsmol/L and/ or inter-eye difference of >8mOsmol/L suggest DED. But whether ophthalmic clinicians require an osmolarity metre next to the slit lamp remains a matter of the automation of DED diagnosis with considerable accuracy. They include the Oculus keratograph, a tomographer that also has an inbuilt infrared camera for meibography. It can also perform interferometry of the lipid layer, noninvasive tear film break-up time, tear film meniscus height measurement and lipid layer evaluation. Other dedicated and multifunctional devices have recently been introduced for clinical use. “If you want to improve your dry eye disease diagnostics, systematically ... it is not an either/or situation. Once screen for signs and symptoms, listen the patient gets trapped in a vicious circle to the patient’s description of their symptoms of discomfort and fluctuating of dry eye disease then both types will be present in the same patient at a vision, look at the slit lamp and don’t forget to use a drop of fluorescein for TBUT and staining, which can tell you certain point in time so much, and don’t forget to inspect and squeeze the meibomian glands,” Dr Carina Koppen MD, PhD Koppen concluded.