David A Luce1. 1. Reichert Inc., Depew, New York, USA. dluce@reichert.com
Abstract
PURPOSE: To study the results of an ocular response analyzer (ORA) to determine the biomechanical properties of the cornea and their relationship to intraocular pressure (IOP). SETTING: Reichert Inc., Depew, New York, USA. METHODS: The ORA (Reichert) makes 2 essentially instantaneous applanation measurements that permit determination of corneal and IOP effects. RESULTS: Measurements of several populations indicate that corneal hysteresis, a biomechanical measure, varied over a dynamic range of 1.8 to 14.6 mm Hg and was only weakly correlated with corneal thickness (r(2)=0.12); this is related to the observation that some subjects with relatively thick corneas have less-than-average corneal hysteresis. Corneal hysteresis changes diurnally, presumably as a result of hydration changes. Keratoconus, Fuchs' dystrophy, and post-LASIK patients demonstrated low corneal hysteresis. CONCLUSION: The corneal hysteresis biomechanical measure may prove valuable for qualification and predictions of outcomes of refractive surgery and in other cases in which corneal biomechanics are important.
PURPOSE: To study the results of an ocular response analyzer (ORA) to determine the biomechanical properties of the cornea and their relationship to intraocular pressure (IOP). SETTING: Reichert Inc., Depew, New York, USA. METHODS: The ORA (Reichert) makes 2 essentially instantaneous applanation measurements that permit determination of corneal and IOP effects. RESULTS: Measurements of several populations indicate that corneal hysteresis, a biomechanical measure, varied over a dynamic range of 1.8 to 14.6 mm Hg and was only weakly correlated with corneal thickness (r(2)=0.12); this is related to the observation that some subjects with relatively thick corneas have less-than-average corneal hysteresis. Corneal hysteresis changes diurnally, presumably as a result of hydration changes. Keratoconus, Fuchs' dystrophy, and post-LASIK patients demonstrated low corneal hysteresis. CONCLUSION: The corneal hysteresis biomechanical measure may prove valuable for qualification and predictions of outcomes of refractive surgery and in other cases in which corneal biomechanics are important.
Authors: Mauro T Leite; Luciana M Alencar; Charlotte Gore; Robert N Weinreb; Pamela A Sample; Linda M Zangwill; Felipe A Medeiros Journal: Am J Ophthalmol Date: 2010-06-11 Impact factor: 5.258
Authors: Brecken J Blackburn; Shi Gu; Matthew R Ford; Vinícius de Stefano; Michael W Jenkins; William J Dupps; Andrew M Rollins Journal: Invest Ophthalmol Vis Sci Date: 2019-01-02 Impact factor: 4.799