Abstract
Purpose: :
To determine the effect of aging upon corneal biomechanical properties, including corneal hysteresis (CH), corneal resistance factor (CRF), and central corneal thickness (CCT) and to explore the relationship between age and intraocular pressure (IOP) measured using the ocular response analyzer (ORA), Goldmann applanation tonometry (GAT), and dynamic contour tonometry (DCT) in eyes of healthy individuals.
Methods: :
All subjects were tested using the ORA, GAT and DCT. CCT and axial length were measured on ninety-five eyes using ultrasound pachymetry and IOLMaster. All measurements were taken within the same session during office hours. Linear and multiple regression analyses were applied to examine the relationship between age and corneal biomechanical properties, (such as CH, CRF, and corneal stiffness i.e., GAT minus DCT), CCT, and axial length. Linear regression analysis was also used to examine the relationship between age and IOP measurements obtained using GAT, ORA, and DCT.
Results: :
CH decreased with age (R2=0.04, P=0.027), while corneal stiffness, as measured by GAT minus DCT, increased with age (R2=0.23, P<0.001). Neither CRF nor CCT was significantly associated with age (R2<0.01, P=0.435 and R2=0.02, P=0.143 respectively). Both ORA Goldmann correlated IOP (IOPg) and corneal compensated IOP (IOPcc) tended to increase with age, but only IOPcc was significant (R2=0.02, P=0.102 and R2=0.05, P=0.009, respectively). IOP measured by GAT also increased significantly with age (R2=0.06, P=0.004), but no significant association was observed between IOP measured by DCT and age (R2=0.03, P=0.056).
Conclusions: :
Corneal biomechanical properties such as corneal hysteresis and corneal stiffness appear to be significantly affected by the aging process. A better understanding of corneal properties and their relation to age is important for a more accurate IOP assessment and to help identify additional risk factors for developing glaucoma.
Keywords: aging • cornea: clinical science