title: The influence of sex hormone levels on tear production in postmenopausal Nigerian women.
abstract: BACKGROUND
  A stable tear film with normal flow is essential for preserving a clear cornea. When the tear film becomes insufficient to support the surface of the eye due to a lack of production of tears or a decrease in stability of tears, dry eye syndrome (DES) occurs. DES is a common disorder of the tear film. It affects a significant percentage of the population, especially women. The onset of dry eye is very common during menopause and may result from the loss of hormonal support.
  
  
  OBJECTIVE
  The purpose of this study was to assess the effect of sex hormone on tear volume and stability in postmenopausal Nigerian women.
  
  
  METHODS
  This study was a cross sectional experimental study. Twenty postmenopausal women aged 50 to 55 years (mean age 52 ± 2.32) and twenty premenopausal women aged 45 to 52 years (mean age 50 ± 2.13) were selected by systematic random sampling. Schirmer's tear test and the noninvasive tear break up time (NITBUT) test were performed on the women. Serum levels of estradiol, progesterone and testosterone were determined.
  
  
  RESULTS
  The differences in mean tear volume, (t = 14.74, p < 0.0001) and tear stability, (t = 11.28, p < 0.04) between the postmenopausal and premenopausal women were statistically significant. Tear volume was positively correlated with testosterone (r = 0.276, p ≥ 0.05) and progesterone (r = 0.227, p ≥ 0.05) but negatively correlated with estradiol (r = 0.141, p ≥ 0.05) in the postmenopausal group, with no statistically significant associations.
  
  
  CONCLUSIONS
  Changes in hormone levels that occur in menopause affect tear volume and tear stability.
authors.forename: J A
authors.initials: JA
authors.lastname: Ebeigbe
authors.forename: P N
authors.initials: PN
authors.lastname: Ebeigbe
mesh_terms: D003430:Cross-Sectional Studies; D015352:Dry Eye Syndromes / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism; D004958:Estradiol / Q000097:blood*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009549:Nigeria; D017698:Postmenopause / Q000097:blood*; D011374:Progesterone / Q000097:blood*; D013666:Tears / Q000378:metabolism*; D013739:Testosterone / Q000097:blood*; D014792:Visual Acuity
chemical_list: D013739:Testosterone; D011374:Progesterone; D004958:Estradiol