title: Evaluation of the relationship between corneal biomechanic and HbA1C levels in type 2 diabetes patients.
abstract: OBJECTIVE
  To evaluate the corneal biomechanical properties due to the glycosylated hemoglobin (HbA1C) levels using the ocular response analyzer (ORA) in the patients with type 2 diabetes mellitus (DM).
  
  
  METHODS
  ORA values were obtained from 156 eyes of subjects with type 2 DM and 74 eyes of healthy control subjects with similar age and sex. Subjects were divided into three groups: Group 1, healthy control subjects; Group 2, diabetes patients with HbA1C <7%; and Group 3, diabetes patients with HbA1C ≥7%. Corneal biomechanical parameters: corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) measurements were obtained using ORA. Ultrasound pachymetry was used for measurement of central corneal thickness (CCT).
  
  
  RESULTS
  CH and CRF were significantly different in each of the three groups (P-values for CH respectively; Groups 1 and 2=0.008, Groups 1 and 3, and Groups 2 and 3, <0.001, and for CRF respectively; =0.002, <0.001, <0.001). CCT was significantly different between Groups 1 and 3 and Groups 2 and 3 (P<0.001) but was insignificant between Groups 1 and 2 (P=0.965). IOPcc was not different between Groups 1 and 2 (P=0.524), and Groups 2 and 3 (P=0.115), but was significantly different between Groups 1 and 3 (P=0.003). IOPg was statistically different between each of the three groups (respectively; Groups 1 and 2, P=0.015, Groups 1 and 3, and Groups 2 and 3, P<0.001).
  
  
  CONCLUSIONS
  Both diabetes groups were affected in terms of corneal biomechanical properties when compared to healthy subjects, there was also a positive correlation between HbA1C level and intraocular pressure.
authors.affiliation: Department of Ophthalmology, Zonguldak Karaelmas University, Zonguldak, Turkey.
authors.forename: Serpil
authors.initials: S
authors.lastname: Yazgan
authors.affiliation: Department of Ophthalmology, Gaziosmanpaşa Taksim Training and Research Hospital, Istanbul, Turkey.
authors.forename: Ugur
authors.initials: U
authors.lastname: Celik
authors.affiliation: Department of Ophthalmology, Bağcılar Training and Research Hospital, Istanbul, Turkey.
authors.forename: Havva
authors.initials: H
authors.lastname: Kaldırım
authors.affiliation: Department of Ophthalmology, Zonguldak Karaelmas University, Zonguldak, Turkey.
authors.forename: Orhan
authors.initials: O
authors.lastname: Ayar
authors.affiliation: Department of Ophthalmology, Pendik Government Hospital, Istanbul, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Elbay
authors.affiliation: Department of Ophthalmology, Gaziosmanpaşa Taksim Training and Research Hospital, Istanbul, Turkey.
authors.forename: Veysel
authors.initials: V
authors.lastname: Aykut
authors.affiliation: Department of Ophthalmology, Beyoglu Eye Training and Research Hospital, Istanbul, Turkey.
authors.forename: Burcu
authors.initials: B
authors.lastname: Celik
authors.affiliation: Department of Ophthalmology, Malatya State Hospital, Malatya, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Taş
keywords: HbA1C; corneal biomechanical parameters; intraocular pressure; ocular response analyzer; type 2 diabetes mellitus