The Tear Film and Ocular Surface Society (TFOS) Dry Eye Workshop II (DEWS II) defines dry eye disease (DED) as “a multifactorial disease of the ocular surface characterized by the loss of homeostasis, and accompanied by ocular symptoms, in which tear film instability, hyperosmolarity, inflammation, and ocular surface damage, and neurosensory abnormalities, play etiological roles.”

Prevalence of DED ranges from 5% to 50%, with rates as high as 75% in adults over 40. DED is primarily divided into two subtypes, aqueous deficient (ADDE) or evaporative (EDE) dry eye. Approximate prevalence of subtypes include:

  • 50% evaporative
  • 15% aqueous deficient
  • 35% combination of both

Although DED is a spectrum of disease rather than distinct subtypes, determining the type of dry eye helps guide treatment strategies.



The TFOS DEWS II diagnostic methodology begins with screening questions. The Dry Eye Questionnaire (DEQ-5) and the Ocular Surface Disease Index (OSDI) are the validated questionnaires used to determine symptoms. Cut-off scores of either ≥6 on the DEQ-5 or ≥13 on the OSDI indicate positive symptoms.

Diagnosis of DED also includes at least one sign of disrupted tear film homeostasis, which is established by measuring tear film stability, tear osmolarity, or ocular surface staining. Diagnostic testing involves:

  • Non-invasive tear break-up time (NIBUT) is preferred to fluorescein TBUT as it does not disrupt tear homeostasis. This test detects break-up time of images from a Placido cone reflected off the cornea. A BUT of <10s indicates tear film instability. The pattern of staining also helps to determine aqueous or mucin deficiency.
  • Tear osmolarity measures salt concentration in tears, which increases when aqueous is deficient. Hyperosmolarity may occur secondary to increased evaporation rates or a reduction in tear secretion. Diagnostic cut-off values of ≥308mOsmol/L in the eye with higher osmolarity or a difference in osmolarity of >8mOsmol/L between each eye reflects loss of homeostasis.
  • Ocular surface staining is assessed with fluorescein and lissamine green dye. Evidence of staining on the cornea (>5 spots), conjunctiva (>9 spots), and lid wiper epitheliopathy (2mm along the lid margin and >25% of its width) indicate DED.

Once DED is confirmed, additional tests to evaluate aqueous deficient and evaporative etiologies include:

  • Tear meniscus height and shape indicates reduced tear volume and production in ADDE. As with NIBUT, the tear meniscus is best measured with noninvasive imaging methods as the use of fluorescein induces reflex tearing and disturbs the tear film. Imaging results are comparable to a Schirmer’s test.
  • Interferometry measures quality and thickness of the lipid layer. An inadequate lipid layer leads to early evaporation. Interferometry also assesses blink dynamics, such as blink frequency and incomplete blinking.
  • Meibography visualizes the morphology of meibomian glands by illuminating the eyelid with infrared light. Meibomian gland dysfunction leads to excessive tear evaporation, increased tear osmolarity, and ocular surface inflammation. Meibography is used to diagnose MGD and monitor efficacy of treatment, such as intense pulsed light therapy.
  • Blepharitis leads to infection, inflammation, increased tear film instability, and rapid tear evaporation. Careful examination of the eyelid margins and eyelash base under high magnification should be performed. Collarettes (cylindrical blepharitis) are indicative of Demodex, while red, thickened eyelid margins and misdirected or missing eyelashes suggest Staphylococcus. Seborrheic blepharitis causes less redness and swelling than staphylococcal blepharitis, but produces more crusting at the eyelash base.



The Ezer Sapphire device is an integrated system that analyzes the ocular surface and identifies subtypes of DED. You can quickly perform a noninvasive and comprehensive dry eye workup in any patient.

A lifestyle questionnaire and the DEQ-5 are included so you can screen patients. All models have anterior segment imaging capability and can be used to assess ocular surface staining, bulbar redness, blepharitis, white to white measurement, and pupillometry.

The device is available in 3 models:

  • Sapphire performs interferometry, NIBUT, meibography, and assessment of tear meniscus height.
  • Sapphire A includes the above, as well as lacrimal topography map and stability chart, eye blink detection, and 3D meibography (composite image).
  • Sapphire A+ also includes auto-interferometry, in addition to the Sapphire A features.

Key benefits of the Sapphire include:

  • Full workup in just 4 minutes
  • Can be performed by ophthalmic technician or other trained staff
  • No added cost or waste of disposables
  • Provides diagnosis and customizable treatment protocol
  • Mounts onto your existing slit-lamp and is removable
  • Software syncs with the smartphone application so you can easily share results and treatment plans with patients
  • Accompanying educational resources, marketing materials, and personalized patient reports
  • Easy-to-read printouts make it simple to show (rather than tell) patients why you’re prescribing a dry eye therapy and how they’ll benefit



With as many as 50% of your patients experiencing signs of DED, a dry eye clinic is a lucrative way to build your practice. The Sapphire device can help you increase dry eye management by incorporating diagnosis and treatment plan into one simple-to-use device. This gives you an advantage over more invasive, expensive, or time-consuming methods of dry eye diagnosis:

  • Many of Sapphire’s diagnostic tests can be billed through insurance
  • You’ll save chair time and testing can be done by the staff
  • Slit-lamp mountable device means no large equipment to take up space in your exam lane
  • Increase patient comfort and satisfaction by avoiding Schirmer tear strips and drops

Increasing practice revenue without significant cost to the patient is possible with Sapphire! For more information on the Sapphire device, please visit our dry eye product page, email us at, or call us at (888) 881-1122.