Dry Eye Signs and Symptoms: The Dry Eye Technician's Role

Dry eye disease (DED) signs and symptoms don’t often correlate and may vary from patient to patient. This can be the most challenging aspect of managing DED patients.

As technicians, identifying these “DED Red Flags” can help us send the patient down the appropriate path of diagnostic testing to better understand their complaint and provide our doctors with all the information they need to make an appropriate diagnosis and recommend the most appropriate treatment for each patient.

No two dry eye patients are the same

Although patient-reported symptoms may be very similar, every patient is different, and their specific circumstances, environmental factors, and behaviors may warrant different approaches. Generally, DED is divided into two primary etiologies: evaporative dry eye and aqueous deficient dry eye.¹

Evaporative dry eye, believed to be the most prevalent form of DED, is thought to be present in over 85% of cases.² Evaporative DED occurs when the lipid layer of the tear film, which prevents evaporation and gives the tear film its lubricating qualities, is deficient or of poor quality.

The leading cause of evaporative DED is generally considered to be dysfunctional meibomian glands (i.e., small sebaceous glands located along the lid margin), although inflammation of the eyelid and environmental factors, such as low humidity, poor blinking, and extended screen time, can also play a role in meibomian gland dysfunction (MGD).¹

Aqueous deficient DED refers to an inadequate level of the watery component of the tear film, known as the aqueous layer, and produced by the lacrimal gland. Aqueous deficient DED is less prevalent as a “stand-alone” disorder, and it may be caused by autoimmune disorders, hormonal changes, systemic medications, and aging, among others.¹

For a deep dive into the difference between evaporative DED and aqueous deficient DED, check out The Ultimate Guide to Evaporative Dry Eye!

What is happening? Common DED symptoms and possible causes:

Watery Eyes: Most patients wouldn’t associate watery eyes (sometimes called epiphora) with dry eyes, but this can indicate that a rapid tear break-up time (TBUT) or lipid deficiency may be causing poor adherence of the tear film to the ocular surface, causing it to dissipate faster.
Fluctuating Vision: An intact and stable tear film is necessary for clear vision. If the vision clears up after blinking repeatedly or after instilling artificial tears, this may be a sign of rapid tear evaporation or a poor-quality tear film. Think of a windshield and what would happen if you rubbed butter on it and turned your wipers on!
Foreign Body Sensation (FBS): Getting an eyelash in the eye—or any foreign object for that matter—can be very irritating. FBS can be caused by a lack of lubrication between the eye and the eyelid because of an inadequate tear film.
Burning, Stinging: The tear film acts as a barrier between the ocular surface and the environment. When that barrier evaporates too quickly or isn’t substantial enough, it can cause the surface of the eye to come into contact with the environment—resulting in that burning or stinging sensation. If you’ve ever had a staring contest, you have an idea of what this feels like after about 30 seconds.
Redness: Red eyes can be a response to irritation in the form of inflammation. Prolonged periods of inadequate lubrication, rapid tear evaporation, and exposure to certain environmental elements can lead the body to produce an inflammatory response—resulting in red, irritated eyes.

When it looks like dry eye, feels like dry eye…but is not dry eye

When we hear patients mention some of the symptoms we have discussed and identified as DED Red Flags, it’s easy to jump to a conclusion and identify the patient as a DED “slam-dunk.” However, many conditions that affect the ocular surface can cause similar symptoms to those we associate with DED.

This is why a thorough examination by our physicians is required to make an adequate diagnosis and recommend an appropriate course of treatment. A robust examination is not complete without the necessary testing, well-documented medical history, and your insight as a technician.

Some examples of conditions with similar symptoms to DED:

Lagophthalmos: Incomplete or partial blinking during the day or at night can lead to DED symptoms—especially upon waking or after long periods of visually tasking activities such as reading, playing video games, driving, or working on the computer.
Conjunctivochalasis: Loose or excessive conjunctival tissue, especially in older patients, can cause watery eyes or epiphora as well as foreign body sensation when blinking.
Allergic Conjunctivitis: The presence of allergens on the ocular surface and papillae—little bumps on the inner surface of the eyelid or palpebral conjunctiva—can cause irritation. This can lead to symptoms that may be easily mistaken for DED, such as itching, burning, redness, and watery eyes.
Demodex Blepharitis: Mites that live on human hair follicles can be present on the eyelashes and cause symptoms of DED. Itching along the lash line, lash loss, redness, and irritation, along with collarettes around the bases of the lashes, can be a sign of Demodex blepharitis.

These are only a few of the conditions we might call DED masqueraders, and as such are unlikely to respond to the most commonly prescribed DED treatments and therapies. When patients have tried every known topical therapy and treatment and have a laundry list of drops, over-the-counter (OTC) remedies, and at-home treatments, you may have a case of “DED that isn’t.”

With some testing and digging, you may help get them closer to finding some much-needed relief, so keep your eyes peeled and your ears wide open!

Dry eye testing: A picture is worth a thousand words

There are many dry eye-specific tests that can help paint a picture of what is happening on a patient’s ocular surface. Additionally, testing can be a powerful patient education opportunity!

A patient who understands their condition is likely to be a more compliant patient; moreover, they will be empowered to better manage their condition and will ultimately be a happier patient.

A full dry eye disease workup would include:

Tear Osmolarity: An objective measure of the concentration of salt in a patient’s tear film. Changes in osmolarity can indicate fluctuations in the water content, not the salt content of the tear film. This could be due to rapid evaporation or low tear production.
- Elevated osmolarity can promote epithelial cell death, which can result in dry eye symptoms.
- The TearLab Osmometer is the only device currently approved in the United States to measure tear osmolarity in a clinical setting.
TBUT: This is one of the easiest and most common tests used to measure the stability of the tear film. Typically measured in seconds, TBUT is the time elapsed between the last blink and the moment the first dry spot forms on the cornea.
- Any measurement below 10 seconds is considered abnormal and indicative of DED.
- TBUT can be done at the slit lamp during the exam portion of the encounter or with imaging devices such as the Oculus Keratograph.
- Non-invasive keratograph break-up time (NIKBUT) allows for break-up time to be measured without the use of diagnostic drops in a controlled, replicable environment that can also be tracked and compared over time.
- It also produces an image that can be used to educate patients on TBUT and how it relates to their symptoms.
InflammaDry: Similar to a COVID-19 test, InflammaDry uses tears collected from the patient to test for MMP-9, an inflammatory enzyme that has been linked to signs of inflammation on the surface of the eye that may be associated with DED symptoms.
- It is recommended that tear samples are collected before the patient has used any eye drops and before any diagnostic drops are used, such as proparacaine, dilating drops, or dyes.
Tear Volume: While there are different ways to measure the amount of tears in a patient’s eye at any given time, the most common are:
- Schirmer’s Test: A paper strip is placed along the patient’s lower eyelid for 5 minutes. As the strip absorbs the tears, we measure in millimeters how far the tears have traveled along the paper.
  - A Schirmer’s test below 5mm would be an indication of deficient tear production. The Schirmer’s test has been around for over 100 years and remains one of the most common ways to test for adequate tear production.
- Phenol-Red Thread Test: Commonly referred to as Zone-Quick, the phenol-red thread test is similar to Schirmer’s but uses yellow cotton thread that is saturated in phenol-red dye (a pH indicator), which turns red when it reacts with alkaline substances like tears.
  - Zone-Quick has some advantages over Schirmer’s test; it takes only 15 seconds, it’s more comfortable for the patient, does not require numbing drops, and can be done in patients wearing contact lenses.
  - Similarly though, we measure how far along the strand tears traveled over a set period of time, using the provided millimeter ruler conveniently provided on the back of the packaging.
- Tear Lake or Tear Meniscus Height: Under the slit lamp or using a device such as the Keratograph, we can measure the height of the tear lake or tear meniscus, the amount of tears collected between the lid margin and the surface of the eye. A normal tear meniscus height will be between 0.25mm and 0.5mm.
- Meibomian Gland Imaging: Located along all 4 eyelids, meibomian glands are responsible for secreting the lipid (i.e., oil) layer of the tear film. A healthy lipid layer is responsible for the stability, clarity, and lubricating properties of the tear film.
  - These glands can become blocked as the oil inside them thickens. Over time, these glands can begin to atrophy and stop producing healthy oils.
  - Using an infrared camera, which may be housed within a device such as LipiScan, LipiView, or Keratograph, we can visualize these glands and determine if any blockage or atrophy has occurred.
  - Doing so can help educate the patient on the need for treatment, and also help us manage the patient’s expectations when it comes to MGD treatments.
- Lissamine Green Staining: Along with traditional fluorescein sodium, lissamine green can help identify devitalized cells on the ocular surface, keratinization of the lid margin, and pooling (accumulation of liquid) on the conjunctiva, all of which are contributing factors to ocular surface discomfort and DED symptoms.

DED: Greater than the sum of its parts

DED is a multifactorial condition, and when it comes to treatments, there is no “one size fits all.” The best way that we can help our doctors is to identify each patient’s symptoms and contributing factors, perform the appropriate tests, and gather as much information as possible to formulate a plan of action.

This also helps our patients to better understand the disease process and better take charge of their personal ocular health management.