Corneal hysteresis measured with the Ocular Response Analyzer® in normal and glaucomatous eyes

Purpose: To identify differences in corneal hysteresis (CH) and central corneal thickness (CCT) between healthy and glaucomatous patients. Methods: Retrospective observational study. One hundred and thirty-three eyes of 75 healthy and 58 glaucomatous patients were included. CH was measured in each patient using Ocular Response Analyzer. CCT was determined by ultrasonic pachymetry. For each patient, one eye was randomly selected. We used a Student t-test to search for significant differences between the different groups (p < 0.05). Results: In healthy and glaucomatous eyes, mean CH values were 10.46 +/- 1.6 and 8.77 +/- 1.4 mm Hg, respectively. Mean CCT values were 560.2 +/- 36.3 and 535.3 +/- 42.7 mu m, respectively. CH and CCT were significantly lower in glaucomatous eyes than in normal eyes, (p < 0.05). Discussion: In our series, CH was lower in glaucomatous than in normal eyes. The relationship between glaucoma, IOP, and ocular structures may not be confined to the consideration of CCT. A low CH value could be responsible for under-estimation of IOP. CH could also be a risk factor for glaucoma, independent of IOP. Further studies are needed to support these hypotheses. Conclusion: In our investigation, CCT and CH were significantly lower in glaucomatous eyes than in healthy eyes.