title: Analysis of Factors Associated With the Tear Film Lipid Layer Thickness in Normal Eyes and Patients With Dry Eye Syndrome.
abstract: OBJECTIVE
  To determine the effects of clinical variables, including age, sex, history of refractive or cataract surgery, contact lens use, and ocular surface and meibomian gland parameters on the lipid layer thickness (LLT) in normal subjects and patients with dry eye syndrome (DES).
  
  
  METHODS
  A total of 64 normal subjects and 326 patients with DES were enrolled, and they underwent measurements of LLT with a LipiView interferometer and tear meniscus height using optical coherence tomography, tear film break-up time (TBUT) determination, ocular surface staining, Schirmer's test, examination of the lid margins and meibomian glands, and assessment using the Ocular Surface Disease Index (OSDI).
  
  
  RESULTS
  In normal subjects, the median (range) LLT was 67 (33-100) nm, and age was the only factor that was significantly associated with LLT (β = 0.678, P = 0.028). In patients with DES, the median (range) LLT was 84 (20-100) nm, and 79.0% of the participants fulfilled the diagnostic criteria for meibomian gland dysfunction (MGD). In a multivariate analysis, increased age and female sex were significantly related to increased LLT (β = 0.282, P = 0.005 and β = 11.493, P < 0.001), and hypersecretory MGD and lid margin inflammation were independently associated with increased LLT (β = 11.299, P = 0.001 and β = 12.747, P = 0.001).
  
  
  CONCLUSIONS
  Lipid layer thickness measurements using a new interferometer are significantly affected by demographic factors such as age, sex, ocular surgical history, and MGD type. Therefore, all of these factors must be considered in the diagnosis of ocular surface diseases.
authors.affiliation: The Institute of Vision Research Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea 2Department of Ophthalmology and Inha Vision Science Laboratory, Inha University School of Medicine, Incheon, South Korea.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Jung
authors.affiliation: The Institute of Vision Research Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Si Yoon
authors.initials: SY
authors.lastname: Park
authors.affiliation: The Institute of Vision Research Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Jin Sun
authors.initials: JS
authors.lastname: Kim
authors.affiliation: The Institute of Vision Research Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Eung Kweon
authors.initials: EK
authors.lastname: Kim
authors.affiliation: The Institute of Vision Research Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Kyoung Yul
authors.initials: KY
authors.lastname: Seo
authors.affiliation: The Institute of Vision Research Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Tae-Im
authors.initials: TI
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015352:Dry Eye Syndromes / Q000175:diagnosis / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007368:Interferometry; D008055:Lipids / Q000032:analysis*; D008297:Male; D008537:Meibomian Glands / Q000378:metabolism*; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013666:Tears / Q000737:chemistry*; D055815:Young Adult
chemical_list: D008055:Lipids