Intraobserver variability of post-mortem corneal thickness measurements by using a portable OCT system.

Purpose : We evaluated the intraobserver variability of post-mortem central corneal thickness (CCT) measurements by using a real-time, portable optical coherence tomography (OCT) system on an animal model. Methods : Participants: Sixteen ocular globes (ovis aries) were analyzed by a portable spectral-domain OCT system (iVue, Optovue Inc, Fremont, CA). All examinations were conducted in the same conditions of temperature (within a range of 12–22°C) and humidity (within a range of 50%–60%) in a dimly lit room. Methods: The OCT scans were performed by two operators at different time-points since death as follows: immediately (i.e. within 10 minutes), at the 30th minute, at the 1st, at the 6th, at the 12th, at the 24th, at the 48th hour, and later (until the 96th hour). Main outcome measures: Repeatability coefficients and intraclass correlation coefficients (ICCs) were calculated for reliability analysis. Results : Results: The coefficient of repeatability ranged from 0.4% to 3.7% in the central region of the cornea. The ICCs were particularly high during different post-mortem intervals, confirming good reliability of measurements with portable OCT. Conclusions : Our results suggest that portable OCT is a reliable approach for monitoring CCT variations after death, which may be useful for characterizing the corneas before explantation, detecting quantitative variations during post-mortem corneal degeneration or assessing changes of CCT for forensic implications.