Numbers transform dry eye treatment for symptomatic, asymptomatic patients

When my colleagues and I decided to expand our range of point-of-care testing and treatment for dry eye, the primary goals were to reduce dry eye discomfort after cataract and refractive surgery and to offer non-surgical patients the relief from dry eye that they have sought for years.

We developed a dry eye centre of excellence, where we routinely screen for dry eye disease according to a standard protocol, and then treat the ocular surface based on individualised plans.

To address both aqueous deficient and evaporative types of the disease, we acquired a range of tests to objectively evaluate the tear film and meibomian glands.

A test intended to measure the osmolarity of human tears (TearLab Osmolarity System, TearLab) tells us the concentration of salts in the tear film. Hyperosmolarity indicates that the film’s aqueous component is reduced, either by evaporation or decreased production, and the patient likely has dry eye.

Another test (TearScope Plus, Keeler) helps us to visualise the tear film, while an infrared camera/meibographer allows us to see and evaluate the meibomian glands.

Because inflammation is part of the dry eye disease process, we use a test (InflammaDry, Quidel) to detect the presence of the inflammatory marker MMP-9. Finally, a tear ferning test shows us whether the tears have a normal or abnormal crystallisation pattern.

These point-of-care tests give concrete, reproducible results that we can share with patients to explain their diagnoses and to monitor the results of treatment over time.

As physicians who have watched the diagnosis of dry eye disease evolve over the years from ambiguous to concrete, objective testing is a welcome addition. From the patient’s perspective, numbers always have a greater, more immediate impact than the subjective opinion of even the most experienced physician.

The power of numbers

In my view, point-of-care testing for dry eye disease has many advantages above and beyond helping us diagnose the problem. One enormous benefit is standardisation.

Tests are consistent, objective and not affected by the differences in perceptions among multiple physicians. A colleague and I may differ in our evaluation of the corneal epithelium or the appearance of the meibomian glands, but our tear osmolarity or MMP-9 test results will be identical.

Concrete numbers and images also help us explain dry eye disease to patients. They can clearly see that their number is not in the normal range for a given test, or see the atrophied meibomian glands we have identified. This evidence is a relief for patients who have suffered with dry eye and received little help.

For asymptomatic patients, objective tests offer proof that they have a problem. This is especially important for patients who are planning laser vision surgery. We explain that surgery reduces tear film production, so it is essential that we take the time to treat dry eye disease before surgery to avoid symptoms later. Based on the evidence, patients are very amenable to treatment. 

Another advantage is that dry eye patients love to see their numbers go down. Once we have our baseline tests in our practice, patients begin treatment, possibly including pulsed light therapy (E-Eye, ESW Vision); prescription medications; artificial tears; warm compresses and other measures.

They see the numbers changing because of therapy, which has much more of an impact than simply hearing “I see the tear film is better than last month”. Some of these patients routinely get numbers for their diabetes or glaucoma, so they already have that mindset.

People like to know that their therapies, including the sometimes monotonous or inconvenient steps they take every day at home, are driving down their numbers. This makes point-of-care testing a powerful, effective tool to get patients on board and encourage them to maintain compliance with therapy. And compliance is essential for this chronic, progressive disease where symptoms improve only once the diagnostic numbers are regularised.

Outcomes

When we began using dry eye point-of-care testing preoperatively for all surgical patients, we found that the problem exists in many more patients than we initially presumed. Many patients can have no symptoms, but tests show a tear osmolarity of 320 mOsms/L, a positive MMP-9 test or other positive results for dry eye disease.

As a result of dry eye diagnosis and intervention before surgical measurements, we have seen more accurate and consistent IOL power calculations. We also have been relieved to find that complaints about postoperative dry eye are now rare for all our surgical patients. Patients understand ocular surface disease and reliably fulfill their role in controlling it long term.

Dr Francesco Carones, MD

Dr Carones is medical director and cataract and refractive surgeon at Centro Oftalmo-Chirurgico Carones, Milan, Italy.