title: Biomechanical properties of the cornea in high myopia.
abstract: OBJECTIVE
  To determine corneal biomechanical properties in patients with high myopia.
  
  
  METHODS
  Observational study.
  
  
  METHODS
  High myopia patients (n=45, age: 37.0+/-12.6 years) with refractive errors of spherical equivalent (SE) greater than -9.00D were recruited in this study along with healthy subjects (n=90, age: 33.7+/-12.4 years) with refractive errors of SE ranging from 0D to -3.00D. Only the right eye was studied. Central corneal thickness (CCT) was measured by optical coherence tomography (OCT). Metrics of corneal biomechanical properties, including corneal hysteresis (CH) and corneal resistance factor (CRF), were measured with the Ocular Response Analyzer (ORA). The ORA also determined the values of intraocular pressure (IOP(g)) and corneal compensated IOP (IOP(cc)).
  
  
  RESULTS
  No significant differences of CCT and CRF were present between the two groups (P=.15 and 0.35 for CCT and CRF, respectively); however, CH in the high myope group was lower than that in the controls (P<.01). IOP(g) and IOP(cc) were both significantly higher in the high myopes compared to the controls. In both groups, there were significant correlations between CH and CCT and between CRF and CCT. CH was not significantly correlated with age in either the control group or the high myope group (P>.05). There was a significant correlation between CH and SE when the two groups were combined for analysis.
  
  
  CONCLUSIONS
  CH, but not CRF, was significantly lower in high myopia patients compared to that in normal subjects. The results indicate that some compromised aspects of the biomechanical properties of cornea may exist in people with high myopia.
authors.affiliation: School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical College, 270 Xueyuan Road, Wenzhou, Zhejiang, China.
authors.forename: Meixiao
authors.initials: M
authors.lastname: Shen
authors.forename: Fan
authors.initials: F
authors.lastname: Fan
authors.forename: Anquan
authors.initials: A
authors.lastname: Xue
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
authors.forename: Xiangtian
authors.initials: X
authors.lastname: Zhou
authors.forename: Fan
authors.initials: F
authors.lastname: Lu
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D001696:Biomechanical Phenomena; D002648:Child; D003315:Cornea / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000473:pathology / Q000503:physiopathology*; D041623:Tomography, Optical Coherence / Q000379:methods