Once upon a time, making the diagnosis of dry eye disease (DED) was based on the height of the tear meniscus, tear film appearance, and fluorescein staining. The whole shebang took about 2 minutes, which is also about the time it took to explain the diagnosis and prescribe artificial tears.

The DED diagnostic devices of today aid eye doctors in making diagnoses of greater specificity, leading to a plethora of treatments geared toward root causes, such as inflammation.

Whether you are diagnosing and treating DED as a part of your core practice or doing so out of necessity for pre- and post-cataract and refractive surgery, your diagnostic accuracy can be enhanced with the addition of diagnostic capabilities.

What follows is a description of the technology with which I am familiar. (See “Additional DED Diagnostics,” below)

Slit Lamp
Everyone has a slit lamp, and everyone has fluorescein staining available. The most basic DED test is to put fluorescein in the tear film and look at tear meniscus height, tear break-up time (TBUT), and the presence and pattern of any corneal or conjunctival staining.

We must now make note of the degree and severity of both conjunctival and lid margin erythema. Our ability to more effectively treat Demodex infestation obliges us to look for and quantify the presence of collarettes.

Additionally, we need a way to objectively record as much of this information as possible to make it dramatically easier to educate our patients about the particulars of their DED, something that will likely increase both their understanding of our suggested treatment plan, as well as their ability to adhere to its details. Slit lamp photos (and videos) of DED patients allow for this.

You can purchase a dedicated slit lamp camera or a slit lamp with an integrated camera. Most of us have been using a cellphone camera with a dedicated docking device for slit lamps. This allows a doctor or technician to use any slit lamp in the office to take a photo, or a video (of TBUT for example).

Tear Osmolarity Testing
Recent research supports the position that elevated osmolarity predicts post-surgical visually significant DED, and that high tear osmolarity itself can be responsible for light scattering equivalent to a moderate cataract.

I use the ScoutPro Osmolarity System (Trukera Medical), which is an accurate and efficient instrument that produces a result for both eyes in a matter of seconds.

Matrix metalloproteinase-9 (MMP-9) Testing
Diagnosing inflammation on the surface of the eye is easy when one encounters fluorescein staining. However, anyone treating DED is familiar with patients who have all the symptoms associated with ocular surface inflammation but have a benign slit lamp exam.

I use InflammaDry (Dry Eye Rescue) in these circumstances, as it can be an accurate indicator for the need to add additional anti-inflammatory medications in these patients.

Lactoferrin and IgE Testing
One encounters the question of underlying etiology when a patient presents with symptoms and signs that could be consistent with both DED and allergic conjunctivitis.

While we have not yet added it to our armamentarium, the T-POC (Verséa Ophthalmics) is an instrument that I have evaluated to test for both lactoferrin, one of the oldest markers of DED, as well as IgE. The system provides a quantitative measurement of both markers.

If the lactoferrin is normal and the IgE is high, signifying allergy as the likely culprit, I evaluate the patient for the presence of environmental allergies. The patient can then be evaluated for the presence of environmental allergies, and treatment can be directed toward addressing allergy prior to DED.

Meibographer
Evaporative DED is now acknowledged to be responsible in part or completely for most of DED. It is regularly associated with meibomian gland dysfunction (MGD).

The more we know about the architecture of the meibomian glands, the more we know about the state of the MGD. Additionally, nothing is more impactful for a patient with MGD than to see their own glands. Therefore, anyone who treats DED based on the type of disease present needs to perform meibography.

I use LipiView (Johnson & Johnson Vision) and LipiScan (Johnson & Johnson), the latter of which is a more compact instrument, to assess meibomian gland health.

Swiss Army Knife Diagnostics
There are a number of multi-DED testing instruments on the market that can be used in a DED clinic. 

I use the Bruder Ocular Surface Analyzer (BOSA) (M&S Technologies/Bruder Healthcare), and I have extensively evaluated the Oculus Keratograph 5M (Oculus). These devices gather and produce an objective report of many of the findings that we describe at the slit lamp. Measured tear meniscus height, non-invasive TBUT, bulbar erythema, tear film break-up effects on topography, and blink quality are all recorded and can be compared over time. Additionally, both devices can perform meibography and lipid interferometry, with the Oculus Keratograph 5M also providing standard topography that can be used in cataract and refractive surgery workups.

When encountering second opinion cases about not only DED but about whether it is DED or some other problem that is the root cause of mysterious visual disturbances, I use the iTrace (Tracey Technologies). This device is a topographer specifically designed for the cataract/refractive practice that is also armed with DED diagnostic capabilities. Specifically, iTrace evaluates the effect of the tear film on topography over time to produce a trackable measure of tear quality. Evaluating the effect of treatment is particularly straightforward. As a practice that sees a very large number of complex DED and postsurgical second opinions, I also appreciate iTrace’s capability of “dissecting” the effect of the tear film, cornea, and lens (or IOL) apart in order to home in on the ultimate culprit behind the vision problem.

For Your Consideration
How, and to what degree you choose to treat DED will determine your diagnostic needs. In the new era of DED treatments in which we can tailor our therapy to a more specific underlying pathophysiology, we are fortunate that our options in the diagnostic equipment domain have kept pace with our treatment capabilities. CP

Darrell E. White, MD is the founder of Skyvision Centers, in Westlake, Ohio. Over the past decade, his focus on the treatment of dry eye has made SkyVision a “Dry Eye Center of Excellence.” Dr. White is a sought-after speaker and consultant on the topic. Relevant disclosures: Trukera Medical (speaker and consultant), Tracey Technologies (consultant), Johnson & Johnson Vision (consultant), and Bruder Healthcare (consultant).