Histology and OCT features of corneal stromal striae in an ovine animal model

Purpose : The aim of our study was to investigate the presence of corneal stromal striae in an ovine animal model (Ovis aries) and to assess the correlation between this OCT sign and the histological appearance. Methods : Forty-six eyes from female adult sheep (older than 2 years), sacrificed at a local slaughterhouse, were involved in our study. After animal decapitation, the eyes were examined by OCT in situ, without enucleation. The instrumental analysis was performed using a portable spectral-domain OCT (SD-OCT) system (iVue SD-OCT, Optovue Inc, Fremont, CA). All OCT scans were performed immediately after death (in a time window of less than 15 minutes), and thereafter the eyes were assigned to a qualified histology laboratory. In order to obtain a minimal tearing, folding and/or the introduction of other artifactitious changes, the corneas were carefully cut and spread in the water bath and properly floated onto a slide. Results : The presence of “V-shaped” stromal striae was detected on OCT in 50% (23/46) of cases and in 78.2% (36/46) of slices on histologic examination. The “V-shaped” stromal striae on OCT and the “V-shaped” linear structure on histologic exams showed angles of 70° ± 5°, and 71° ± 5°, respectively. There exists a significant correlation between the stromal striae observed on OCT and a variable number of “V-shaped” linear structures on histologic slides (Spearman’s ρ= 0.98, p<0.01). Conclusions : The present study demonstrated the existence of stromal striae in an ovine animal model, thus suggesting their ubiquity in mammals.