title: Evaluation of sex differences in corneal hysteresis.
abstract: OBJECTIVE
  To study sex differences in corneal biomechanical parameters in Egypt as regards to corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc).
  
  
  METHODS
  This is a cross-sectional observational study that includes 350 eyes of 350 normal subjects (175 men and 175 women) who were evaluated using the Reichert ocular response analyzer (ORA) to measure CH, CRF, IOPg, and IOPcc.
  
  
  RESULTS
  The mean CH in men was 9.69 ± 2.05 mm Hg (range 5.7-14.6 mm Hg) and in women 10.41 ± 1.65 mm Hg (range 7-14.4 mm Hg) with a p value of 0.00038. The mean CRF in men was 9.54 ± 2.16 mm Hg (range 4.9-14.4 mm Hg) and in women was 10.37 ± 1.71 mm Hg (range 7.3-15.5 mm Hg) with a p value of 0.00008. The mean IOPg in men was 14.78 ± 4.15 mm Hg (range 7.2-26.5 mm Hg) and in women was 15.44 ± 3.3 mm Hg (range 8.6-23.7 mm Hg) with a p value of 0.09. The mean IOPcc in men was 16.2 ± 4.08 mm Hg (range 10.9-28.9 mm Hg) and in women was 15.86 ± 3.41 (range 9.7-24.2 mm Hg) with a p value of 0.4. There was a statistically significant difference between men and women in CH and CRF while IOPg and IOPcc showed no statistically significant difference (p&gt;0.05).
  
  
  CONCLUSIONS
  There is a statistically significant difference between men and women in CH and CRF, where women show higher values, while no statistically significant difference exists between the groups in IOPg or IOPcc.
authors: Kasr Al-ainy School of Medicine, Cairo University, Cairo - Egypt.
authors: Riham S H M
authors: RS
authors: Allam
authors: Noha M M M
authors: NM
authors: Khalil
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003315:Cornea / Q000502:physiology*; D003430:Cross-Sectional Studies; D004548:Elasticity / Q000502:physiology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D012737:Sex Factors; D014065:Tonometry, Ocular; D055815:Young Adult