title: Comparison of ocular response analyzer parameters in primary open angle glaucoma and exfoliative glaucoma patients.
abstract: OBJECTIVE
  We sought to identify differences in the following measures of the ocular response analyser (ORA) between primary open angle glaucoma (POAG) and exfoliative glaucoma (EXG) patients: Corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg). We also sought to relate these ORA measures with central corneal thickness (CCT).
  
  
  METHODS
  This cross-sectional study was conducted on a total of 162 individuals (46 EXG patients, 66 POAG patients and 50 healthy subjects without any ocular and systemic disease). ORA measurements were performed, and a minimum of three readings were obtained from each test subject. Groups were compared according to their ORA parameters.
  
  
  RESULTS
  The mean CH levels of the EXG, POAG and healthy subjects were 7.6 ± 2.1, 9.1 ± 1.9 and 9.6 ± 1.7 mmHg, respectively. CH was significantly lower in the EXG patients compared to the other groups (P < 0.001).The mean CRF levels of the EXG, POAG and healthy subjects were 9.0 ± 2.0, 10.1 ± 1.7 and 9.8 ± 1.8mmHg, respectively. CRF levels in the eyes of the EXG patients were significantly lower compared to those of either the POAG patients (P = 0.005) or the healthy subjects (P = 0.03), but there was no significant difference in CRF levels between the POAG patients and the healthy subjects (P = 0.59). There was a significant positive correlation between CH and CCT in the EXG patients and healthy subjects (P < 0.001), but this correlation was not present in the POAG patients (P = 0.70).
  
  
  CONCLUSIONS
  In this study, CH and CRF were found to be significantly reduced in the eyes of EXG patients compared to both the POAG patients and healthy subjects. Reduced CH in EXG patients might result in decreased support of peripapillary scleral structure and increased damage to the optic nerve during IOP increase.
authors.affiliation: Department of Ophthalmology, Gazi Mustafa Kemal State Hospital, Ankara, Turkey.
authors.forename: Emrullah
authors.initials: E
authors.lastname: Beyazyıldız
authors.forename: Ozlem
authors.initials: O
authors.lastname: Beyazyıldız
authors.forename: Hasan Basri
authors.initials: HB
authors.lastname: Arifoğlu
authors.forename: Ayşegül Koçak
authors.initials: AK
authors.lastname: Altıntaş
authors.forename: Sükrü Gültekin
authors.initials: SG
authors.lastname: Köklü
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D003315:Cornea / Q000503:physiopathology*; D063171:Corneal Pachymetry; D003430:Cross-Sectional Studies; D004548:Elasticity; D017889:Exfoliation Syndrome / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005902:Glaucoma, Open-Angle / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014065:Tonometry, Ocular; D014794:Visual Fields / Q000502:physiology*