Repeatability and reproducibility of post-mortem central corneal thickness measurements using a portable optical coherence tomography system in humans: a prospective multicenter study

Abstract

To assess the repeatability and reproducibility of post-mortem central corneal thickness (CCT) measurements made by the portable iVue spectra-domain (SD) optical coherence tomography OCT (Optovue Inc, Fremont, CA) system in humans, and to prospectively establish the time-course of CCT after death. In a prospective multicenter setting, CCT measurements were obtained from 58 human eyes at the following 16 time-points after death: immediately (within 2 h), and at each hour by the next 17 h. The range of CCT values for each subject was determined and longitudinal data were used to illustrate the variation in open and close eye mode. All measurements were made by two independent and well-trained examiners for session. Main outcome measures were intraclass correlation coefficients (ICC), repeatability and reproducibility coefficients, and coefficients of variation of the average central (0–2 mm). Overall, a total of 5,568 OCT measurements were performed by examiners. The repeatability coefficient varied from 0.3 to 1.7% and the reproducibility coefficient varied from 0.3 to 1.6% throughout the entire experimental time frame. Furthermore, the values of the different ICCs were also high during the different postmortem intervals, thus demonstrating the excellent repeatability and reproducibility of the present OCT approach. When CCT measurements were analyzed longitudinally, corneal thickness showed different behavior based on the open or close eye mode. The present study demonstrates that portable OCT imaging can be reliably used for corneal pachymetric measurements in supine subjects and during the post mortem period, i.e. without visual fixation and normal physiology/architecture of examined tissues.