Rethinking the Postmortem Pupil: Biological Insights Through the Standardization of Miosis and Mydriasis

Background/Objectives: Postmortem pupillary assessment remains qualitative and lacks standardized quantitative criteria. The Pupil-to-Iris Ratio (PIR), a described photographic morphometric measure, enables objective postmortem pupil characterization independent of image magnification. This study aimed to establish a standardized PIR framework, characterize baseline postmortem pupillary morphology, and investigate its biological determinants.

Methods

Retrospective study of 83 forensic cases (166 eyes) with postmortem intervals of 3–288 h. Digital photographs were analyzed using a semi-automated workflow. A predefined proposed operational PIR classification was applied. Associations with age, sex, postmortem interval, cause of death, and toxicology were evaluated using mixed-effects models and generalized estimating equations.