Determining pupillary reaction time using pilocarpine eye drop – A post mortem study

Post-mortem miotic changes in the pupil using pharmacological solutions have been a topic of discussion among researchers as well as medico-legal experts to determine time since death. For many decades, researchers used different methods such as eye drop method and injection method to observe pupillary changes as convenience to make this study useful in the autopsy room. However, different researchers also used the different onset of reaction time to observe pupillary miotic changes without testing its effectiveness. The objective of the present study is to determine the reaction time for effective post mortem miotic changes in pupil using pilocarpine eye drops. Total 200 deceased with known time of death were instilled with the 2% pilocarpine eye drop into conjuctival sac and changes were analysed using ImageJ freeware every 10 minutes up to 50 minutes. In this study, author observed no statistically significant difference in reactivity of both the eyes in different time interval in different sex (p= 0.097). However, significant difference found in reactivity of both the eyes in different time interval in different age group (p= 0.0006) and cause of death (p = 0.015) at α < 0.05 using t-test and one way ANOVA test. Author concluded that left eye reacts faster than right eye and a significant number of pupillary miotic changes are observed up to 30 minutes. Therefore, minimum 30 minutes are effective time period to observe post mortem pupillary miotic changes for pilocarpine eye drop which could be useful to determine time since death. This is the first study of its kind on an Indian population.