Repeatability of Corneal Hysteresis Measurements in Glaucoma Patients During Routine Follow Up and After Cataract Surgery

Precis:Corneal hysteresis (CH) measurements are relatively stable during routine follow up of glaucoma patients over an intermediate time frame. Cataract surgery does not change the CH significantly after an average follow up of 6 months. Purpose:The aim was to assess the repeatability of CH measurements in glaucoma patients over time, during routine follow up and after cataract surgery. Materials and Methods:Retrospective analysis of patients records in a glaucoma clinic where routine measurements by the Ocular Response Analyzer were done. Patients with at least 2 CH measurements were included. Repeatability was assessed using the intraclass correlation coefficient (ICC). Results:A total of 164 eyes (87 patients) were included. Twenty-eight of them had measurements before and after cataract surgery with mean follow up time of 29.64 +/- 9.63 weeks. There was no evidence for a difference in CH between the before and after cataract surgery measurements (ICC=0.79, 95% confidence interval: 0.60-0.89). In the remaining 136 eyes, without any surgical treatment between measurements, there was moderate agreement among the repeated CH measurements (ICC=0.64, 95% confidence interval: 0.61-0.82) with mean time of 32.06 +/- 25.32 weeks between first and last measurement. Conclusion:CH measurements in glaucoma patients were repeatable over a 6-month period during routine follow up or following cataract surgery. These findings suggest that the intraocular pressure reduction following cataract surgery is unlikely to be because of a change in this biomechanical property.