Tear break-up time
After a blink the tear film should stay smooth for at least ten seconds. In dry eye it breaks up sooner, exposing patches of the cornea. It is measured with fluorescein dye at the slit lamp, or without dye by an imaging system that watches the reflection of a pattern on the tear surface. A short break-up time is the hallmark of evaporative dry eye and is also why vision fluctuates between blinks.
Tear osmolarity
A tiny sample of tears is drawn from the lower lid margin and its salt concentration is measured in seconds. Healthy tears are around 300 milliosmoles per liter; dry eyes are higher and, importantly, the two eyes differ. Osmolarity grades severity and is one of the more objective ways to track improvement with treatment.
MMP-9 inflammation testing
Matrix metalloproteinase 9 is an enzyme released by an inflamed ocular surface. A rapid in-office test, similar to a pregnancy test in format, detects it in a tear sample within ten minutes. A positive result means inflammation is part of your dry eye and that anti-inflammatory treatment, such as cyclosporine or lifitegrast drops, is likely to help; a negative result steers treatment elsewhere.
Meibography
Infrared imaging through the everted eyelid shows the meibomian glands as pale stripes. Healthy glands are long and parallel; in meibomian gland dysfunction they are truncated, dilated or missing. The percentage of gland loss is graded, and it predicts how much a gland treatment can recover: glands that are blocked can be cleared, glands that are gone cannot.
Lipid layer interferometry
Light reflected from the tear film produces interference colors that reveal the thickness of its oil layer, measured in nanometers. A thin lipid layer confirms that the glands are not delivering enough oil, and the measurement is repeated after treatment to show the change.
Schirmer test and tear meniscus
A small paper strip placed under the lower lid for five minutes measures how much tear is produced; a low result indicates aqueous deficient dry eye, seen in Sjogren's syndrome and with age. The height of the tear meniscus, the strip of tears along the lower lid, can be imaged as a gentler alternative.
Surface staining
Fluorescein and lissamine green dyes highlight cells on the cornea and conjunctiva that are damaged or dying from dryness. The pattern and extent of staining grade the damage and show where the tear film is failing.
Is this right for your eyes?
Nothing on this page is a diagnosis. Whether this is the right choice for you is decided by a full examination at one of our 4 offices: Pasadena, Huntington Beach, Woodland Hills and Beverly Hills.
About this content: This page was written with the assistance of AI tools and reviewed for medical accuracy by Dr. Bavand Youssefzadeh, DO. It is general information, not medical advice, and does not replace an eye examination. Individual results vary. Read our medical disclaimer.
