title: Corneal Biomechanical Properties in Patients With Arcus Senilis.
abstract: OBJECTIVE
  To compare the corneal biomechanical properties and intraocular pressure (IOP) levels in patients with and without arcus senilis (AS).
  
  
  METHODS
  Ocular response analyzer measurements were performed on the right eyes of 37 patients with AS (group 1) and 37 control eyes (group 2). Corneal hysteresis, corneal resistance factor, Goldmann-correlated IOP, and corneal compensated IOP were recorded with Ocular response analyzer. Spherical equivalent value of the refractive errors, axial length, central corneal thickness, and IOP measured with Goldmann applanation tonometer were noted for each study eyes. Statistical analyses were performed with Student t, Kruskal-Wallis, and Pearson correlation tests.
  
  
  RESULTS
  Mean age was 67.6 ± 9.8 years in group 1 and 65.3 ± 8.1 years in group 2 (P = 0.308). Mean corneal hysteresis and corneal resistance factor readings were 9.8 ± 0.9 versus 10.6 ± 0.8 (P < 0.001) and 10.05 ± 1.07 versus 10.9 ± 0.9 (P < 0.001) in groups 1 and 2, respectively. Mean corneal compensated IOP and Goldmann-correlated IOP values were found as 16.1 ± 3.3 mm Hg versus 15.8 ± 2.6 mm Hg (P = 0.719) and 15.1 ± 3.3 mm Hg versus 15.0 ± 2.6 mm Hg (P = 0.912) in groups 1 and 2, respectively. There was no statistical difference in IOP measured with Goldmann applanation tonometer, central corneal thickness, spherical equivalent value of the refractive error, axial length measurements, and mean keratometry readings between the 2 groups (P = 0.983, P = 0.289, P = 0.938, P = 0.886, P = 0.07, respectively).
  
  
  CONCLUSIONS
  The mean corneal hysteresis and corneal resistance factor values of eyes with AS were lower when compared with the controls. This study demonstrated that AS may change the corneal biomechanical properties.
authors.affiliation: Department of Ophthalmology, Dokuz Eylul University School of Medicine, Izmir, Turkey.
authors.forename: Ziya
authors.initials: Z
authors.lastname: Ayhan
authors.forename: Taylan
authors.initials: T
authors.lastname: Ozturk
authors.forename: Mahmut
authors.initials: M
authors.lastname: Kaya
authors.forename: Gul
authors.initials: G
authors.lastname: Arikan
authors.forename: Uzeyir
authors.initials: U
authors.lastname: Gunenc
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001112:Arcus Senilis / Q000503:physiopathology*; D058452:Axial Length, Eye; D001696:Biomechanical Phenomena; D003315:Cornea / Q000502:physiology*; D004548:Elasticity / Q000502:physiology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014065:Tonometry, Ocular; D014792:Visual Acuity / Q000502:physiology