Over the past 10 years, the eye care industry has seen a surge in the dry eye disease (DED) diagnostic technologies available to the practitioner. While the added assurance of objective clinical testing is a boon for the ocular surface clinician, it also presents us with some challenges as to how to prioritize the additional data, how to coalesce it with our patient’s subjective symptoms, and, perhaps most importantly, how to explain the aggregate results to our patients. This article will focus on the latter. (See "DED Diagnostic Products," p.22.)

The importance of our patients’ understanding the tests we are running, their data and what it means to us and patients cannot be overstated. The better our patients understand their own disease, the more likely they will be compliant with the recommendations we give them from a treatment and management standpoint, which improves DED outcomes in our practices. (See "Educate on DED Therapeutics," p.24.)

PRESENTING THE INFORMATION

A myriad of ways exist to assess and explain diagnostic devices to patients. I’ve tried going test-by-test but, especially as the number of tests we have access to increases, I’ve found the information to be more digestible to the patient when it is broken down by category. This method is simply a summation of the data produced by the tests we have in our offices. (It differs from the DEWS2 summation in that in DEWS2, by definition, DED presents with a loss of homeostasis.)

1. Tear quality metrics: osmolarity, inflammation and TBUT
2. Tear quantity metrics: Schirmer, tear meniscus height (via biomoscropy and/or AS-OCT)
3. Ocular surface structural analysis: meibography, vital dye staining, blink mechanics

Classification into these three categories helps in patient retention and simplifies the data presentation. As we also will be comparing results over time, this summation method assists in instilling in patients the importance of complying with follow-up visits.

The following are scripts to use or adapt in each of the major areas outlined above.

DED DIAGNOSTIC PRODUCTS

Tear Quality Measurements  

• I-Pen Tear Osmolarity System (I-Med Pharma)
• Inflammadry (Quidel)
• TearLab Osmolarity System (TearLab)
• Vapor Pressure Osmometer Model 5520 (Wescor)

   Tear Quantity Measurements 

• Cirrus (ZEISS)
• iVue (Optovue)
• Nidek RS 3000
• OSData (Ophthalmic Resources)
• SMTube (OSD Care)
• Spectralis (Heidelberg)
• TearFlo (HUB Pharmaceuticals)
• Triton (Topcon)
• Zone-Quick (Menicon)

   Ocular Surface Structure Analysis

• Aladdin HW 3.0 (Topcon Medical Systems)
• Atlas 9000 (Zeiss)
• BlinkCam (BlinkCam)
• CA-200F Corneal Analyzer (Topcon Medical Systems)
• CA-800 Corneal Analyzer (Topcon Medical Systems)
• EasyScan (EasyScan USA)
• Flexx MG Expressors (OcuSci)
• Galilei Dual Scheimpflug Analyzer (Ziemer Group)
• iPEDA (Ophthalmic Resources)
• KR 7000P (Topcon Medical Systems)
• LipiScan (TearScience)
• LipiView (TearScience)
• Mastrota Paddle (Medi Instruments)
• Meibomian Gland Evaluator (Johnson & Johnson)
• Meibox (Box Medical Solutions)
• Oculus Keratograph 5M (Oculus)
• OPD Scan III (Marco)
• Orbscan III (Bausch + Lomb)
• Tearscope (Keeler)
• TMS-4N (AIT Industries)
• Visionix VX110 Multi-Diagnostic Unit (AIT Industries)
• Visionix VX120 Multi-Diagnostic Unit (AIT Industries)
• Zeiss Atlas 992 (Zeiss)

* This list is evolving and will be updated online.

TEAR QUALITY

A general explanation of how we might start the conversation about tear quality measurements with patients may look like this: “We will be performing a few different tests to help to assess the quality of your tears; that is, the tears are complex and need to behave a certain way to protect the surface of your eye. If there is too much salt, which is called osmolarity, this has negative effects. If there is inflammation, this is another important marker. Specifically, inflammation leads to an inability of the tears to protect the surface of the eye and also can contribute to the breakdown of the cells there. Next, we will look at the ability of the tear film to protect the surface of the eye. Each of those is an important marker.”

• Explaining osmolarity. “This is a test that measures the salt, or ionic, content of the tears. This number is higher in patients who have DED. This test is very good at telling me whether your eyes are dry. The numbers will increase as dryness worsens. The test also will tell me the difference in dryness between the eyes.”
• Explaining inflammatory markers. “This test measures the amount of a specific molecule in the tears associated with inflammation. The specific item this looks for is a regulatory enzyme normally present in small amounts in the tear film, but it increases when there is stress on the ocular surface cells. This test will not give us an exact number, but it will tell us whether you are outside the normal range.”
• Explaining TBUT. “This test will be measuring what we call your tear break-up time, which is the amount of time after a blink when the surface of the cornea is protected by the tear film. After you blink, we will measure the time it takes for the first separation of the tears to take place; this is normally at least five seconds, but the longer the better.”

ADVANCED TEAR DIAGNOSTICS

   Additional diagnostic devices are being tried, and research is emerging as to how to use them These include:

• Corneal sensitivity: bit.ly/30QZewv
• Strip meniscometry: bit.ly/3hy1te5
• Epithelial thickness mapping: bit.ly/3fvgOdm
• Impression cytology: bit.ly/2ANcM1l
• Confocal microscopy: bit.ly/2ABKAP3

See larger sidebar in the online version of this article.

TEAR QUANTITY

Explaining tear quantity is generally easier. After all, the colloquialism that most patients are familiar with is “dry eye,” so it makes sense to them that one of the critical categories we may be looking at is a decrease in tear volume.

• Explaining Schirmer/Phenol red thread test. “This test measures the amount of fluid your eyes are producing. There are a couple ways for us to assess this: Schirmer’s strips measure the ability for your eyes to produce any kind of fluid. Generally, we will not use anesthetic with this test. Alternatively, with the phenol red thread test, we can roughly measure the amount of tears your eyes produce on a regular basis.”
• Explaining tear meniscus height: “This test will give us a good idea of the balance between how many tears your eyes are producing and how many tears your eyes are losing. There needs to be a balance between tear production and tear outflow. Any change in that balance will show up here.”

OCULAR SURFACE STRUCTURE

This is, perhaps, the most difficult portion to describe to patients, but it also is, perhaps, the most powerful. Ocular surface architecture is less abstract than say, inflammation, tear quality and tear volume. When we think of it from the patient's perspective, we are discussing an actual, physical part of their body they may not have been aware of or have given much thought to.

This means we should be taking extra care to use words that are not presumptive or conjectural, but based on fact. To be honest, even I have a somewhat difficult time with ocular surface structure because this is an area where we are lacking some basic scientific information as well.

• Explaining meibography. “This test shows us the images of the structure of the oil-secreting glands of the eyelid. These glands are important because they secrete a substance thought to help protect against evaporation and redistribute tears across the surface of the eye. We can see various changes: shortening of the gland, curviness (tortuosity) or kinking of the gland, among others, that may come about progressively by stressors, such as inflammation. It is unclear whether we can regenerate gland tissue, but we know we can improve and maximize the efficiency and function of the glands you do have.”
• Explaining vital dye utilization. “The instillation of certain dyes into the tear film allows us to view a couple of items. The yellow dye, or sodium fluorescein, can highlight gaps in between cells on the cornea that result from dehydration, for example cells that shrink and shrivel up, due to dryness.
  “Vital dye also shows any large breaks or loss of surface cells. It can even highlight areas on the cornea that are elevated. Spots that stick up may also cause problems. The green dye, or lissamine green, shows us areas where the cell membrane is compromised, dead or near death. These areas can show up on the cornea, but we mainly use the dye to look at the conjunctiva, or the white part of the eye.”
• Explaining incomplete blink. “The blink process is vital to smooth the tear film out over the surface of the eye, and the blink itself contributes to the tears by helping to push out the oily substance from the glands in the eyelid. If you have a high percentage of incomplete blinks, this leads to increased exposure of the ocular surface of the eye to air, creating discomfort and damage to the surface of the eye.

“The blink is affected by many things, including your natural anatomy, any eye or lid surgeries and the amount of time you spend engaged in near work, which includes reading and time on your smartphone.”

A PLETHORA OF INFORMATION AVAILABLE

A plethora of diagnostic devices and methods are available for quantifying the aspects of the tear film and ocular surface. It is up to the clinician to choose which tests seem right for their practice modality and patient demographics. (See "How to Create a DED Clinic," p.34, for additional information related to practice management and DED.)

Regardless of the testing employed, it is most helpful if the clinician can relay what information is being gathered by performing each of the tests and relaying that information to the patient. This action step is important, as it helps to breed an understanding of the nature of that patient’s specific problem and may help to foster the doctor-patient relationship through trust, information exchange and education. OM

DR. HAUSWIRTH is an assistant professor of ophthalmology and director of the Dry Eye Center of Colorado at the University of Colorado School of Medicine.