title: Corneal biomechanical properties of patients with pseudoexfoliation syndrome.
abstract: OBJECTIVE
  To assess the corneal biomechanical properties of patients with pseudoexfoliation syndrome (PEX syndrome).
  
  
  METHODS
  Fifty-two eyes of 52 patients (27 unilateral and 25 bilateral) and 42 eyes of 42 age-matched control subjects were enrolled in the study. 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 Goldmann-correlated intraocular pressure and corneal-compensated intraocular pressure. Central corneal thickness (CCT) was measured by the ORA integrated handheld ultrasonic pachymeter. The values recorded by the ORA were compared between eyes with PEX syndrome and those without PEX syndrome. Eyes with unilateral PEX syndrome and fellow eyes without PEX syndrome were also compared.
  
  
  RESULTS
  The mean CH and CRF of all eyes with PEX syndrome were significantly lower than those of control eyes (P < 0.05). Neither corneal-compensated intraocular pressure nor Goldmann-correlated intraocular pressure showed a statistically significant difference in both the groups. Mean CCT values also did not show significant difference. Comparison of the unilateral eyes with PEX syndrome with the apparently normal fellow eyes revealed no significant difference between the mean CCT, mean CH, and mean CRF values (P > 0.05). However, the mean corneal-compensated intraocular pressure and Goldmann-correlated intraocular pressure were relatively higher in the PEX syndrome eye (P < 0.05). There was no significant difference between the mean CCT values of these groups (P > 0.05).
  
  
  CONCLUSIONS
  The CH and CRF decrease in both unilateral and bilateral PEX syndrome suggested that PEX syndrome has a weakening effect on corneal biomechanical properties. Moreover, in subjects with clinically unilateral PEX syndrome, these properties were closer to eyes with PEX syndrome than to normal control eyes.
authors.affiliation: Department of Ophthalmology, Faculty of Medicine, Yeditepe University, Istanbul, Turkey. meldayen@hotmail.com
authors.forename: Nursal Melda
authors.initials: NM
authors.lastname: Yenerel
authors.forename: Ebru
authors.initials: E
authors.lastname: Gorgun
authors.forename: Raciha Beril
authors.initials: RB
authors.lastname: Kucumen
authors.forename: Deniz
authors.initials: D
authors.lastname: Oral
authors.forename: Umut Asl
authors.initials: UA
authors.lastname: Dinc
authors.forename: Ferda
authors.initials: F
authors.lastname: Ciftci
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena / Q000502:physiology; D003315:Cornea / Q000503:physiopathology*; D004108:Dilatation, Pathologic; D004547:Elastic Tissue / Q000503:physiopathology*; D004548:Elasticity / Q000502:physiology*; D017889:Exfoliation Syndrome / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D014065:Tonometry, Ocular