title: Corneal hysteresis and Beta-zone parapapillary atrophy.
abstract: OBJECTIVE
  To evaluate the relationship between β-zone parapapillary atrophy (βPPA) and corneal hysteresis (CH) in patients with glaucoma.
  
  
  METHODS
  Prospective, cross-sectional study.
  
  
  METHODS
  Glaucoma patients aged 18 to 90 years with disc photographs within 12 months of the study visit were consecutively enrolled. Exclusion criteria included ocular surgery other than clear corneal phacoemulsification, myopia >6 diopters, contact lens use, and corneal abnormality. CH was measured using the Ocular Response Analyzer (ORA). Disc photographs were evaluated in a masked fashion for βPPA.
  
  
  RESULTS
  We enrolled 99 patients (mean age 67.6 years; 45 men, 54 women). Univariate analysis showed no significant difference in CH between eyes with and without βPPA (8.72 ± 0.23 vs 8.15 ± 0.27 mm Hg, P = .11). There were no differences in corneal resistance factor (CRF) (P = .47), central corneal thickness (CCT) (P = .11), ORA wave score (P = .23), age (P = .23), sex (P = .40), IOP (P = .86), or visual field mean deviation (VFMD) (P = .45). Eyes with βPPA were more myopic (-1.49 ± 0.27 vs -0.22 ± 0.31 diopters, P = .003). Multivariate analysis showed no significant difference in CH between eyes with and without βPPA (P = .38). Eyes with asymmetric βPPA also showed no significant difference in CH (8.97 ± 0.22 vs 9.10 ± 0.22 mm Hg, P = .69).
  
  
  CONCLUSIONS
  We found no significant differences in CH between eyes with and without βPPA or between fellow eyes with asymmetric βPPA.
authors.affiliation: Einhorn Clinical Research Center, New York Eye and Ear Infirmary, New York, New York, USA.
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Hayes
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Teng
authors.forename: Carlos Gustavo
authors.initials: CG
authors.lastname: de Moraes
authors.forename: Celso
authors.initials: C
authors.lastname: Tello
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Liebmann
authors.forename: Robert
authors.initials: R
authors.lastname: Ritch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D003315:Cornea / Q000502:physiology*; D003430:Cross-Sectional Studies; D004548:Elasticity / Q000502:physiology*; D005260:Female; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009896:Optic Atrophy / Q000503:physiopathology*; D009898:Optic Disk / Q000473:pathology*; D018583:Pliability / Q000502:physiology*; D011446:Prospective Studies; D014065:Tonometry, Ocular; D055815:Young Adult