Abstract
Purpose :
Dark scleral spots (DSSs) represent an often described but hitherto poorly understood “eye sign” in forensic medicine and vision sciences. They are currently considered a non-specific phenomenon essentially attributable to dehydration of the ocular surface. The aim of the current work is to acquire more knowledge on the morphology and pathogenesis of this sign by optical coherence tomography (OCT) imaging in human and in an animal model during the early post-mortem period.
Methods :
The study was divided into two phases: the first one on an animal model, and the second one on humans. In the first experiment, 66 eyes (33 heads) of adult sheep (age >2 years) were analyzed by OCT and without enucleation. The animals were sacrificed in a local slaughterhouse and the heads stored at known temperatures and humidity. The right eye was kept open by eyelids excision. The left one was instead kept closed with releasable sutures and checked at hourly intervals. Scleral scans were performed at each macroscopically detectable DSS.
In the second phase, the human cadavers arriving at the Legal Medicine Institute were scanned by OCT on DSSs without varying the state of opening or closing of the eyelids. Out of 30 corpses examined, only one had the required characteristics. The sample consisted of a 30-year-old male who committed suicide from a gunshot wound to the head. The imaging data was viewed and interpreted by two expert ophthalmologists who were part of the team.
Results :
In the animal model, no scleral changes were found in eyes kept closed. On the other hand, in the open eyes, the DSSs appeared in all the samples in the superior sclera between the 3rd and 6th post-mortem hours. On OCT imaging, DSSs appeared as areas of hyper-reflectivity in the scleral tissue. Moreover, DSSs were surprisingly associated with choroid-scleral detachment in all cases. The same morphological picture was found in the human case.
Conclusions :
From our preliminary data, we can assume that scleral dehydration is a necessary element for the pathogenesis of DSSs. However, the presence of choroidal detachment suggests that other pathophysiological mechanisms may be important, e.g., different post-mortem events or the dynamics of death.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.