title: Diurnal and zonal analysis of corneal surface temperature in young healthy adults.
abstract: OBJECTIVE
  To determine diurnal changes and zonal differences of corneal surface temperature in young healthy adults following blinking.
  
  
  METHODS
  In this prospective, longitudinal, single-center study, 19 healthy left eyes of 19 healthy subjects (age 23.6 ± 2.2 years) were recruited. Corneal surface temperature (CST) was measured by the Ocular Surface Thermographer TG-1000 (Tomey, Germany) at 3 different time points: 8:00-10:00, 11:00-13:00, and 15:00-18:00. The CST was measured every second for 10 seconds immediately after blinking. We assessed the temperature at the corneal center and at 3 peripheral quadrants at 3 (temporal), 6 (inferior), and 9 (nasal) o'clock at the corneal limbus.
  
  
  RESULTS
  Mean central/temporal/nasal/inferior corneal surface temperatures were, between 11:00 and 13:00, 34.1 ± 0.5°C/34.2 ± 0.6°C/34.4 ± 0.5°C/34.6 ± 0.5°C. During 10 seconds following eye opening and between time points 1, 2, and 3, the observed corneal surface temperature parameters did not change significantly (p>0.3 for all). However, there was a significant difference between temperatures at the nasal limbal area and the center of the cornea (p<0.03 at each time point). In addition, the temperature was warmer nasally than temporally until 6 seconds and 8-10 seconds after blinking (p<0.05 for seconds 0-6; 8-10 at time points 1, 2, and 3).
  
  
  CONCLUSIONS
  In healthy subjects, corneal surface temperature does not change diurnally and is warmer nasally than centrally and temporally during the interblinking interval. Our study leads to the assumption that diurnal changes of corneal temperature indicate ocular surface abnormality or corneal pathology.
authors.affiliation: Department of Ophthalmology, Saarland University Medical Center, Kirrberger Strasse 1, Homburg/Saar, Germany.
authors.forename: Sarah
authors.initials: S
authors.lastname: Moussa
authors.forename: Timo
authors.initials: T
authors.lastname: Eppig
authors.forename: Johanna
authors.initials: J
authors.lastname: Pattmöller
authors.forename: Elena
authors.initials: E
authors.lastname: Zemova
authors.forename: Berthold
authors.initials: B
authors.lastname: Seitz
authors.forename: Achim
authors.initials: A
authors.lastname: Langenbucher
authors.forename: Nóra
authors.initials: N
authors.lastname: Szentmáry
mesh_terms: D000328:Adult; D001767:Blinking / Q000502:physiology; D001831:Body Temperature / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D003315:Cornea / Q000502:physiology*; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D008297:Male; D055815:Young Adult