Tests
1st tests to order
tear film meniscus height (meniscometry)
Test
Measured using slit-lamp beams.
Normal range is 0.1 mm to 0.5 mm.
Measurement gives crude indications of aqueous volumes.
May be done by digital devices or by spectral-domain optical coherence tomography, which demonstrates good repeatability and reliability.
Result
reduced height may indicate aqueous deficiency
tear film/fluorescein breakup time (TFBUT)
Test
Assesses tear film stabilities.
Fluorescein (2%) is instilled into conjunctival sacs and TFBUT measured using slit lamps. TFBUT is defined as time that lapses between the last complete blinks and the appearance of dry spots or disruptions in the tear films.[3]
Sensitivity 72% and specificity 62% in patients with Sjögren syndrome.[3]
Result
<10 seconds is diagnostic (depending on the volume of fluorescein instilled)
Schirmer test
Test
Assesses aqueous tear production and involves leaving Schirmer paper strips in closed eyes for 5 minutes.[1]
When performed without anesthesia, Schirmer test measures the total secretion (i.e., reflex and basic). When the test is performed with anesthesia, it measures basic secretion.
Schirmer paper strips are placed midway between the middle and outer thirds of lower lid margins in unanesthetized eyes, and eyes are closed.
Slit lamps are not used.
Sensitivity 77% to 85% and specificity 70% to 83%.[3]
Result
<10 mm of wetting after 5 minutes (some use <5 mm after 5 minutes as cut-off)
Emerging tests
tear film osmometry
Test
Measures tear film osmolarity using a tear osmometer. It is not widely available and is used in academic settings more often than in clinical practice.[3]
Sensitivity 64% to 91%, specificity 78% to 96%, and positive predictive value 85% to 98%.[3]
Result
values of ≥308 milliosmols/L; inter-eye difference of >8 milliosmols/L; values of ≥316 milliosmols/L are better in differentiating moderate to severe dry eye disease (DED)
metalloproteinase-9 (MMP-9) detection
Test
A rapid in-office test that detects MMP-9, an inflammatory marker that has consistently been shown to be elevated in the tears of patients with dry eye.[25]
Result
positive result: >40 nanograms/mL (but the result is not specific to the source of ocular surface inflammation)
corneal topography
Test
A noninvasive imaging method for mapping the surface curvature of the eye. Newer instruments can provide images and videos of tear film breakdown, tear meniscus height, and nontouch tear film break-up time.
Result
may show corneal or tear film abnormalities
ocular surface interferometry
Test
An imaging device that can be used to capture specular observations of the tear film, meibomian glands under near-infrared illumination, and the ocular surface and eyelids under white illumination.
Result
may show tear film, meibomian gland, or ocular surface abnormalities
infrared thermography
Test
A noninvasive imaging device that allows measurement of the ocular surface temperature during the interblink period.
A faster cooling rate of the ocular surface is associated with patients with DED. This is presumably related to a higher rate of tear film evaporation.
Result
faster cooling rate of the ocular surface
in-vivo confocal microscopy
Test
A noninvasive imaging technique that allows evaluation of ocular surface damage in DED at a cellular level.
Result
may reveal decreased corneal/conjunctival epithelial cell density, decreased goblet cell density, and conjunctival squamous metaplasia
ocular surface immune markers (OSIM)
Test
Impression cytology can be performed to harvest conjunctival epithelial cells for evaluation of surface markers.
Most commonly used OSIM is HLA-DR expression.[34] Increased expression correlates with increased severity of DED but it can be very variable.
Result
HLA-DR expression
Use of this content is subject to our disclaimer