title: Reliability of the drop test for the lacrimal drainage function.
abstract: OBJECTIVE
  The purpose of this study was to investigate the reliability of the drop test.
  
  
  METHODS
  The repeatability of the test was studied with the same and three different examiners. The influence of the blink rate was investigated by recording the blink frequency in 63 subjects. The degree of reflex lacrimation during the test was assessed in ten patients. The effect of different test solutions was investigated in ten test subjects.
  
  
  RESULTS
  There was no significant difference when the test was repeated either by the same or different examiners. The reflex lacrimation during the drop test was not significant. There was no correlation between drop test result and blink rate. A moderate increase in the viscosity of the test solution affected the lacrimal drainage.
  
  
  CONCLUSIONS
  The drop test is a reliable test for the lacrimal drainage function.
authors.affiliation: St Erik's Eye Hospital, The Karolinska Institute, Stockholm, Sweden. sven.sahlin@ophste.hs.sll.se
authors.forename: S
authors.initials: S
authors.lastname: Sahlin
authors.forename: E
authors.initials: E
authors.lastname: Chen
authors.forename: B
authors.initials: B
authors.lastname: Philipson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001767:Blinking / Q000502:physiology; D002648:Child; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000008:administration & dosage*; D007765:Lacrimal Apparatus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions / Q000008:administration & dosage; D015203:Reproducibility of Results; D012965:Sodium Chloride / Q000008:administration & dosage*; D013666:Tears / Q000378:metabolism*
chemical_list: D009883:Ophthalmic Solutions; D012965:Sodium Chloride; D006820:Hyaluronic Acid