| dc.description.abstract | Pupillary changes after death have long been a topic of interest for researchers and
medico-legal specialists in determining the time of death. Pupillary changes after
death can provide valuable information for determining the time of death. The eye
drops method and the injection method are two commonly used techniques for
monitoring pupillary changes.
The eye drops method involves instilling a mydriatic or miotic agent into the
eye and monitoring the subsequent changes in pupil size. Mydriatic agents such as
atropine cause the pupils to dilate, while miotic agents such as pilocarpine cause the
pupils to constrict. The time it takes for the pupil to reach its maximum size or
minimum size can be used to estimate the time of death.
However, these methods can vary in terms of onset of reaction times, which
can affect the accuracy of the results. It is important to note that while the study of
pupillary changes after death can provide valuable information, it is just one factor
that is considered in determining the time of death. Other factors, such as the ambient
temperature, the presence of rigor mortis, and the level of lividity, are also taken into
account. It is also important to understand that determining the time of death with
certainty can be challenging, and that different methods may yield different results.
As such, it is always advisable to consider multiple sources of information and to use
caution when interpreting the results of any single method.
The objective of the present study is to determine the reaction time for
effective miotic changes in pupil diameter, comparison between the changes in pupil
diameter in left and right eye and make regression equation between pupillary
changes and post mortem interval in different cause of death using pilocarpine eye
drops. Total 583 deceased (1166 eyes) of known time of death were instilled with the
2% pilocarpine eye drop into conjunctival sac and changes were analysed using
ImageJ freeware. 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= 0.0007) 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
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than right eye and a significant number of pupillary miotic changes are observed up to
30 minutes.
The author observed no statistically significant difference between the
reactivity of the left and right eye (p = 0.4446, at α < .05). A negative correlation
between the changes of pupil diameter under the influence of the pilocarpine eye drop
showed less change with increase PMI. Pearson correlation showed the negative
correlation between the pupillary changes with PMI with p value 0.0001, 0.00017,
0.0341 and 0.0021 where α=0.05 for natural death, hanging, burn and poisoning
respectively.
Effective onset of reaction time for pupillary miotic alterations caused by
pilocarpine eye drops should be around 30 minutes. While the largest number of cases
across all age groups showed a reaction after 20 minutes, there were still instances
where miotic changes occurred in 30 minutes. Additionally, there was a significant
decrease in pupillary constriction after 30 minutes, and no reaction was observed in
either eye after 40 minutes. Therefore, it would be reasonable to recommend waiting
at least 30 minutes before assessing the effectiveness of pilocarpine eye drops in
causing pupillary miotic alterations.
Based on the information provided, it seems that both the right and left eyes
react identically for all different causes of death, but the left eye tends to show better
reactivity in a greater number of cases. This suggests that the left eye may be a more
reliable indicator for determining time since death.
Final results of the study suggest that a different regression equation should be
applied when determining postmortem interval (PMI) based on the various causes of
death. It is important to note that the limited number of samples for the various causes
of death could be a factor contributing to the potential misinterpretation of the results. | en_US |
