Effect of Aging on Corneal Biomechanical Parameters Using the Ocular Response Analyzer

<jats:sec> <jats:title>Purpose:</jats:title> <jats:p>To assess the effect of aging on corneal biomechanical parameters in a normal population.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods:</jats:title> <jats:p> We prospectively examined 204 normal eyes of 204 healthy Japanese volunteers (68 men, 136 women; mean age 46.7±19.4 years [range: 19 to 89 years]). Corneal hysteresis, corneal resistance factor, corneal-compensated intraocular pressure (IOP <jats:sub>cc</jats:sub> ), and Goldmann-correlated intraocular pressure (IOP <jats:sub>G</jats:sub> ) were qualitatively assessed using a Reichert Ocular Response Analyzer. Central corneal thickness was measured using an ultrasound pachymeter. This measurement was performed 3 times, and the mean value obtained was used for statistical analysis. The relationships between patient age and corneal biomechanical parameters, or age and intraocular pressure (IOP), were investigated. </jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p> Mean corneal hysteresis and corneal resistance factor were 10.1±1.5 mmHg and 10.1±1.6 mmHg, respectively. Mean central corneal thickness was 539.1±30.9 µm. A weak, but significant, negative correlation was found between age and corneal hysteresis (Pearson's correlation coefficient r=−0.17, <jats:italic>P</jats:italic> =.02) and corneal resistance factor (r=−0.18 <jats:italic>P</jats:italic> =.01). On the other hand, no significant correlation was found between age and central corneal thickness (r=−0.06, <jats:italic>P</jats:italic> =.41), age and IOP <jats:sub>cc</jats:sub> (r=−0.02, <jats:italic>P</jats:italic> =.82), or age and IOP <jats:sub>G</jats:sub> (r=−0.11, <jats:italic>P</jats:italic> =.11). </jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions:</jats:title> <jats:p> Corneal biomechanical parameters are significantly decreased by aging without significant changes in central corneal thickness or IOP, suggesting that age-related structural changes resulting from collagen cross-linking may lead to a reduction of corneal biomechanical variables independent of central corneal thickness or IOP. [ <jats:italic>J Refract Surg</jats:italic> . 2009;25:888–893.] </jats:p> </jats:sec>