Evidence map›Paper›PMID 42192072›Full record

ArticleOphthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists)2026

Diurnal Variation of Tear and Meibum Lipids in Healthy Subjects.

Mukesh Kumar, Ankit Raj, Ajay Kumar Vijay, Srikanth Dumpati, Simin Masoudi, Mark Willcox

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Article in Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists), 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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4 · The record

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5 · Who and what money

Authors and funding

6 authors.

Mukesh Kumar *School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.
Ankit Raj *LV Prasad Eye Institute, Hyderabad, India.
Ajay Kumar VijaySchool of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.
Srikanth DumpatiSchool of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.
Simin MasoudiSchool of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.
Mark WillcoxSchool of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia. m.willcox@unsw.edu.au.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeTo determine whether the lipid composition of tears and meibum demonstrates diurnal variation in healthy individuals, with emphasis on the relative distribution of lipid classes.

methodsFifteen non-contact lens wearers (10 females, 5 males; mean age 29.5 ± 11.6 years) provided morning (09:00-10:00 h) and evening (16:00-17:00 h) tear and meibum samples. Tears were collected with Schirmer strips without anaesthesia, and meibum was expressed from the lower lid margin using a Korb expressor and collected with a sterile spatula under slit-lamp guidance. Lipids were extracted in chloroform and analysed by mass spectrometry. Relative molar proportions of wax esters (WE), cholesteryl esters (CE), triglycerides (TG) and polar lipid classes were quantified.

resultsNon-polar lipids comprised most tear lipids in the morning (98.8%) and evening (99.0%), with WE being most abundant, followed by CE and TG. No significant diurnal differences were observed in tear lipid class proportions. Meibum lipid composition was also dominated by non-polar species (99.4% morning; 99.2% evening), with WE as the principal component. TG levels were higher in evening meibum, while diacylglycerol and phosphatidylserine were significantly elevated among polar lipids (p = 0.04 and p = 0.03, respectively).

conclusionThe overall distribution of major non-polar lipids in tears and meibum remains stable throughout the day in healthy individuals. Minor changes in specific lipid classes suggest potential molecular-level modulation, the functional relevance of which warrants further investigation.

Indexed as

Circadian RhythmLipidsMeibomian GlandsTearsAdultFemaleHealthy VolunteersHumansMaleMass SpectrometryYoung AdultLipidsMeibomian glandsMeibumMeibum compositionMeibum lipidsTears

Identifiers

PMID42192072
PMCPMC13395822

What Socratic holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.