title: Effects of eye rubbing and breath holding on corneal biomechanical properties and intraocular pressure.
abstract: OBJECTIVE
  To determine whether corneal biomechanical properties and intraocular pressure (IOP) are affected by eye rubbing and breath holding.
  
  
  METHODS
  Corneal hysteresis, corneal resistance factor, corneal compensated IOP (IOPcc), and Goldmann equivalent IOP (IOPg) were measured on both eyes of 40 subjects. Measurements were taken at baseline before eye rubbing (ER(0)) and before breath holding (BH(0)), immediately after 2 episodes of eye rubbing (ER(1) and ER(2)), and during 2 episodes of breath holding (BH(1) and BH(2)).
  
  
  RESULTS
  Corneal hysteresis, corneal resistance factor, and IOPg were significantly lower after ER(1) compared with ER(0) and were significantly lower after ER(2) compared with ER(1). In contrast, IOPcc did not decrease significantly. There were no significant differences among BH(0), BH(1), and BH(2) in any of the 4 outcomes.
  
  
  CONCLUSIONS
  Eye rubbing should be avoided before measurements of corneal biomechanical properties and IOPg. In contrast, breath holding during measurements is not likely to cause a significant change in IOPg and IOPcc or corneal biomechanical properties.
authors.affiliation: Department of Ophthalmology, Taoyuan Veterans Hospital, Taoyuan, Taiwan.
authors.forename: Wan-Cherng
authors.initials: WC
authors.lastname: Liu
authors.forename: Shui-Mei
authors.initials: SM
authors.lastname: Lee
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Graham
authors.forename: Meng C
authors.initials: MC
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology*; D003315:Cornea / Q000502:physiology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008405:Massage; D008875:Middle Aged; D009799:Ocular Physiological Phenomena; D015656:Respiratory Mechanics / Q000502:physiology*; D014065:Tonometry, Ocular; D055815:Young Adult