title: Variations in central corneal thickness during the menstrual cycle in women.
abstract: OBJECTIVE
  We report changes in the central corneal thickness during various phases of the menstrual cycle.
  
  
  METHODS
  We recruited 16 healthy women of reproductive age and measured the central corneal thickness at 3 points in their menstrual cycle, beginning on days 1 to 3 and again at ovulation and at the end of the cycle (days 27-32). Ovulation was determined with a test that determines the peak of luteinizing hormone in the urine.
  
  
  RESULTS
  We found that the central cornea was thinnest at the beginning of the cycle (mean = 536 microm). Corneal thickness increased at ovulation (mean = 549 microm) and at the end of the cycle (mean = 559 microm). The difference in corneal thickness was statistically significant at ovulation (P = 0.003) and the end of cycle (P = 0.001) compared with values at the beginning of the cycle.
  
  
  CONCLUSIONS
  The central corneal thickness changes during the menstrual cycle; the cornea is thinnest at the beginning of the cycle and thickest at the end. These changes could be secondary to hormonal influences; estrogen receptors can be found in human corneas, suggesting that estrogen may have a role in corneal physiology.
authors.affiliation: University Eye Clinic, Department of Neurology, Ophthalmology and Psychiatry, University of Palermo, Palermo, Italy. giuseppe.giuffre@aliceposta.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Giuffrè
authors.forename: Luigi
authors.initials: L
authors.lastname: Di Rosa
authors.forename: Fabio
authors.initials: F
authors.lastname: Fiorino
authors.forename: Daniele Morreale
authors.initials: DM
authors.lastname: Bubella
authors.forename: Gaetano
authors.initials: G
authors.lastname: Lodato
mesh_terms: D000328:Adult; D001837:Body Weights and Measures; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D004967:Estrogens / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008597:Menstrual Cycle / Q000502:physiology*; D012016:Reference Values; D014463:Ultrasonography; D014792:Visual Acuity
chemical_list: D004967:Estrogens