Inter-examiner Reproducibility of Ocular Response Analyzer Using the Waveform Score Quality Index in Healthy Subjects

Abstract

To evaluate the inter-examiner reproducibility of Ocular Response Analyzer (ORA) parameters in healthy subjects using the waveform score (WS) for quality control of acquisition. Fifteen healthy subjects had their intraocular pressure (IOP) measured with ORA by 2 masked examiners. An acquisition protocol that aimed at obtaining 4 reliable measurements in each eye with WS≥6 and with as few repeated measurements as possible was employed, whereas a maximum of 8 measurements per eye was allowed. Additional good quality criteria included symmetrical force-in and force-out applanation signal peaks on the ORA waveform and few or no distortions of the applanation signal curve. Only the right eyes were included in the analysis. Examiners were trained but not experienced. The inter-examiner reproducibility of ORA parameters was assessed using the intraclass correlation coefficient (ICC). Mean values of the best 4 measurements were considered in analysis. ICC including the best 4 measurements per eye was high for all ORA parameters. Specifically, ICC for Goldmann-correlated IOP was 0.961, for corneal-compensated IOP was 0.962, for corneal resistance factor was 0.987, and for corneal hysteresis was 0.988. Similar reproducibility was found when only the 3 best measurements per eye were included in the analysis. The protocol for IOP measurement with ORA using the WS ≥6 as quality index achieved high inter-examiner reproducibility for all ORA parameters. High reproducibility was obtained even by inexperienced examiners when considering the mean of the best 3 measurements per eye.