title: Correlation of vitamin D levels with tear film stability and secretion in patients with dry eye syndrome.
abstract: OBJECTIVE
  To investigate tear film stability and secretion according to serum 25-hydroxyvitamin D3 [25(OH)D] levels in dry eye patients.
  
  
  METHODS
  In this retrospective observational study, the medical charts of 92 patients who visited the Department of Ophthalmology at Hallym University Kangnam Sacred Heart Hospital from April to August 2015 were reviewed. Serum 25(OH)D levels were measured. Subjects were divided into three groups according to serum 25(OH)D levels: sufficient, inadequate or deficient group. Eye discomfort was measured by ocular surface disease index (OSDI). Tear break-up time (TBUT), fluorescein staining score and Schirmer's tear secretion test were measured.
  
  
  RESULTS
  The mean age was 53.38 ± 13.69 years. Mean serum 25(OH)D level was 14.41 ± 5.98 ng/ml. Tear break-up time (TBUT) and tear secretion were positively correlated with serum 25(OH)D levels (r = 0.389, p = 0.001; and r = 0.428, p < 0.001, Pearson correlation test). Tear break-up time (TBUT) and tear secretion were shorter in the vitamin D-deficient group compared to the sufficient group (p = 0.022 and p = 0.004). Fluorescein staining scores and OSDI scores were not different between the three groups.
  
  
  CONCLUSIONS
  Tear break-up time (TBUT) and secretion were correlated with serum vitamin D levels. Vitamin D status may be an important factor for dry eye syndrome.
authors.affiliation: Department of Ophthalmology, Hallym University College of Medicine, Seoul, Korea.
authors.forename: Ki Won
authors.initials: KW
authors.lastname: Jin
authors.affiliation: Department of Ophthalmology, Hallym University College of Medicine, Seoul, Korea.
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Ro
authors.affiliation: Department of Ophthalmology, Hallym University College of Medicine, Seoul, Korea.
authors.forename: Young Joo
authors.initials: YJ
authors.lastname: Shin
authors.affiliation: Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi, Korea.|Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Hyon
authors.affiliation: Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Won Ryang
authors.initials: WR
authors.lastname: Wee
authors.affiliation: Department of Occupational and Environmental Medicine, Inha University School of Medicine, Incheon, Korea.
authors.forename: Shin Goo
authors.initials: SG
authors.lastname: Park
mesh_terms: D003941:Diagnostic Techniques, Ophthalmological; D015352:Dry Eye Syndromes / Q000175:diagnosis / Q000378:metabolism*; D005260:Female; D019793:Fluorescein / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013499:Surface Properties; D013666:Tears / Q000378:metabolism*; D014807:Vitamin D / Q000097:blood*
chemical_list: D005456:Fluorescent Dyes; D014807:Vitamin D; D019793:Fluorescein
keywords: dry eye syndrome; serum 25-hydroxyvitamin D3; tear break-up time; tear secretion