title: Ocular response analyzer to assess corneal biomechanical properties in exfoliation syndrome and exfoliative glaucoma.
abstract: BACKGROUND
  The aim of this work was to investigate the differences in corneal biomechanical parameters between healthy and exfoliation syndrome (EXS) and exfoliative glaucoma (EXG) patients.
  
  
  METHODS
  Two hundred and forty-four eyes of 102 healthy, 64 EXS, and 78 EXG patients were included in the study. Corneal biomechanical parameters were measured using an ocular response analyzer (ORA). Central corneal thickness (CCT) was measured with an ultrasonic pachymeter. The differences in ORA parameters between study and control group participants were analyzed using Student's t test.
  
  
  RESULTS
  In healthy subjects, EXS and EXG eyes mean corneal hysteresis (CH) values were 9.4 ± 1.4 mmHg, 8.5 ± 1.5 mmHg and 6.9 ± 2.1 mmHg, respectively. The difference in mean CH between the EXG and the other two groups were statistically significant (p < 0.01 for both comparisons). CH was significantly lower in EXS patients than that of healthy eyes (p < 0.001). Mean corneal resistance factor (CRF) values were 9.8 ± 1.6 mmHg, 9.3 ± 1.8 mmHg and 9.5 ± 2.6 mmHg, respectively. Except for the difference between the control and EXS eyes (p = 0.004), no statistically significant difference was found between the groups in relation to mean CRF. There were no significant differences in CCT between the control eyes and exfoliative eyes with or without glaucoma.
  
  
  CONCLUSIONS
  In this study, CH was found to be significantly lower in eyes with exfoliation. Further studies are needed to establish the relationships between exfoliation, ocular biomechanics, and glaucoma.
authors.affiliation: M.D. Ulucanlar Eye Research Hospital, Ankara, Turkey. abcankaya@hotmail.com
authors.forename: Ali Bulent
authors.initials: AB
authors.lastname: Cankaya
authors.forename: Alpaslan
authors.initials: A
authors.lastname: Anayol
authors.forename: Dilek
authors.initials: D
authors.lastname: Özcelik
authors.forename: Elif
authors.initials: E
authors.lastname: Demirdogen
authors.forename: Pelin
authors.initials: P
authors.lastname: Yilmazbas
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D003315:Cornea / Q000000981:diagnostic imaging / Q000502:physiology*; D003430:Cross-Sectional Studies; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D004548:Elasticity / Q000502:physiology*; D017889:Exfoliation Syndrome / Q000503:physiopathology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000503:physiopathology*; D006068:Gonioscopy; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D014065:Tonometry, Ocular; D014463:Ultrasonography