title: Tear osmolality and ferning patterns in postmenopausal women.
abstract: OBJECTIVE
  To compare tear osmolality and ferning patterns in postmenopausal women (PMW) with and without dry eye symptoms.
  
  
  METHODS
  Thirty-seven healthy PMW (>50 years of age), not on hormone replacement therapy, were categorized as being symptomatic or asymptomatic of dry eye based on their responses to an Allergan "Single-Item Score Dry Eye Questionnaire" (SIDEQ). They subsequently completed the Allergan "Ocular Surface Disease Index" (OSDI) questionnaire. Tear samples were collected from participants to evaluate osmolality and ferning patterns. A novel freezing point depression osmometer (Advanced Instruments Inc., Model 3100 Tear Osmometer), was used to measure the osmolality of the tear film. The tear ferning test was performed and evaluated for the quality of ferning based on the Rolando grading system.
  
  
  RESULTS
  SIDEQ responses revealed 21 symptomatic and 16 asymptomatic participants. The OSDI total score was 6.5 +/- 5.9 for the non-dry-eyed (NDE) group and 25.7 +/- 12.4 for the dry-eyed (DE) group. The subscores for the DE group were significantly greater than the NDE group (p < 0.001). Osmolality values in DE individuals were significantly different from NDE (328.1 +/- 20.8 vs. 315.1 +/- 11.3 mOsm/kg; p = 0.02). Fifty percent of the DE participants showed type II ferning patterns and 29% of the DE participants showed type III ferning patterns, whereas the NDE participants showed either type I (44%) or II (66%) ferning patterns. There was a significant difference between the DE and NDE participants for the ferning patterns (p = 0.019). There was no significant correlation between tear osmolality and tear ferning (DE: r = 0.12; p > 0.05, NDE: r = -0.17; p > 0.05).
  
  
  CONCLUSIONS
  Osmolality in mild and moderately DE PMW is higher than in NDE PMW and tear ferning is a rapid, simple, noninvasive laboratory procedure that indicates altered tear quality in PMW with symptoms of dry eye.
authors.affiliation: Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ontario, Canada. s2sriniv@uwaterloo.ca
authors.forename: Sruthi
authors.initials: S
authors.lastname: Srinivasan
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Joyce
authors.forename: Lyndon W
authors.initials: LW
authors.lastname: Jones
mesh_terms: D000368:Aged; D015352:Dry Eye Syndromes / Q000378:metabolism*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009994:Osmolar Concentration; D017698:Postmenopause / Q000378:metabolism*; D011379:Prognosis; D013499:Surface Properties; D011795:Surveys and Questionnaires; D013666:Tears / Q000737:chemistry*