title: Tear osmolarity and tear film parameters in patients with unilateral pterygium.
abstract: OBJECTIVE
  The aim of this study was to evaluate the differences in tear osmolarity and tear film parameters between pterygium-affected and healthy fellow eyes.
  
  
  METHODS
  The study enrolled 65 patients with unilateral pterygium. Tear osmolarity, tear film break-up time (TBUT), Schirmer I test measurements, fluorescein corneal staining, and conjunctival redness were evaluated. The results were compared between pterygium-affected eyes and healthy fellow eyes of the same patient (controls). The pterygium thickness was measured using optical coherence tomography. We also evaluated the relationship between pterygium thickness and tear osmolarity and between TBUT and Schirmer I test results in eyes with pterygium.
  
  
  RESULTS
  The mean tear osmolarity was 307 mOsm/L in pterygium-affected eyes and 294 mOsm/L in control eyes. The mean values of TBUT, Schirmer I test, corneal staining, and conjunctival redness scores were 10.3 ± 3.4 seconds, 14.8 ± 9.2 mm, 1.2 ± 1.1, and 0.9 ± 0.9 in the pterygium group, whereas the mean values were 12.3 ± 4.4 seconds, 16.2 ± 7.2 mm, 0.4 ± 0.8, and 0.4 ± 0.7 in the control group, respectively. Eyes with pterygium had significantly higher tear osmolarity levels, corneal staining, and conjunctival redness scores; and lower tear film TBUT and Schirmer I test values than eyes without pterygium (Wilcoxon signed rank test, P < 0.05). There was no significant correlation between pterygium thickness versus tear osmolarity, TBUT, and Schirmer I test values in eyes with pterygium (r = 0.159, 0.738, 0.321, respectively; P > 0.05).
  
  
  CONCLUSIONS
  This study showed that pterygium is associated with tear hyperosmolarity and abnormal tear film function.
authors.affiliation: Department of Ophthalmology, Istanbul Medipol University, Istanbul, Turkey.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Ozsutcu
authors.forename: Banu
authors.initials: B
authors.lastname: Arslan
authors.forename: Sevil K
authors.initials: SK
authors.lastname: Erdur
authors.forename: Gokhan
authors.initials: G
authors.lastname: Gulkilik
authors.forename: Selim M
authors.initials: SM
authors.lastname: Kocabora
authors.forename: Orkun
authors.initials: O
authors.lastname: Muftuoglu
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D015352:Dry Eye Syndromes / Q000503:physiopathology*; D017097:Electric Impedance; D005260:Female; D015590:Fluorophotometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D061286:Osmometry; D011625:Pterygium / Q000503:physiopathology*; D013666:Tears / Q000737:chemistry / Q000502:physiology*; D041623:Tomography, Optical Coherence