A Prospective Longitudinal Study to Investigate Corneal Hysteresis as a Risk Factor for Predicting Development of Glaucoma

Abstract

To investigate the role of corneal hysteresis (CH) as a risk factor for development of glaucoma. Prospective observational cohort study. Two hundred and eighty-seven eyes of 199 patients suspected of having glaucoma were followed for an average of 3.9 ± 1.8 years. All eyes had normal visual fields at baseline. Development of glaucoma was defined as occurrence of 3 consecutive abnormal standard automated perimetry tests during follow-up, defined as pattern standard deviation (PSD) < 5%, and/or Glaucoma Hemifield Test outside normal limits. Measurements of CH were acquired at baseline using the Ocular Response Analyzer (ORA). Univariable and multivariable Cox regression models were used to investigate baseline factors associated with development of visual field loss over time. Fifty-four (19%) eyes developed repeatable visual field defects during follow-up. Measurements of CH at baseline were significantly lower in patients who developed glaucoma vs those who did not (9.5 ± 1.5mm Hg vs 10.2 ± 2.0mm Hg; P= .012). Each 1-mm Hg lower CH was associated with an increase of 21% in the risk of developing glaucoma during follow-up (95% confidence interval [CI]: 1.04-1.41; P= .013). In a multivariable model adjusting for age, intraocular pressure, central corneal thickness, PSD, and treatment, CH was still predictive of development of glaucoma (hazard ratio= 1.20; 95% CI: 1.01-1.42; P= .040). Baseline lower CH measurements were significantly associated with increased risk of developing glaucomatous visual field defects over time. The prospective longitudinal design of this study supports a role of CH as a risk factor for developing glaucoma.