Which parameter is used to indicate aqueous deficient dry eye based on tear film measurement?

• A. Tear Film Osmolarity
• B. Corneal Sensitivity
• C. Tear Film Break-Up Time
• D. Tear Meniscus Height

Answer: (D)

Aqueous-deficient dry eye is about having less tear volume from the lacrimal glands. The tear meniscus height directly measures the amount of tear fluid stored at the lower lid margin, so a lower height indicates reduced tear reservoir and thus aqueous deficiency. This makes tear meniscus height the most specific tear film parameter for assessing aqueous deficiency, especially when tears can be measured noninvasively with imaging or slit-lamp methods.

Tear film osmolarity tends to rise in dry eye as the tear film becomes more concentrated, but it reflects overall tear film imbalance rather than the actual tear volume from the lacrimal glands. Tear film break-up time assesses how long the tear film stays intact and can be shortened in both aqueous-deficient and evaporative dry eye, so it isn’t specific to aqueous deficiency. Corneal sensitivity relates to nerve function on the cornea, not tear volume, so it’s not a tear film measurement of aqueous deficiency.