Study of vitreous potassium for the estimation of time since death

This study was undertaken to study the concentration of vitreous humour after death and find out the reliability of potassium concentration of vitreous humour for the estimation of time passed since death. The material for the study consisted of 165 cases brought for medicolegal autopsy to the Mortuary of Forensic Medicine, Regional Institute of Medical Sciences, Imphal, Manipur. The potassium levels in vitreous humour were found to increase in a linear fashion upto 108 hours. The rate of rise was 039 mEq/L per hour with standard error of ±5.6 hours. The 95% confidence of potassium concentration were ±11 to ±13 hours. The levels of vitreous potassium were found to be the same, when the vitreous samples from both eyes were drawn at the same time and were examined as separate samples. There was no statistically significant difference in the concentration of potassium in the vitreous humour between the two eyes. In the vitreous humour, the potassium concentration showed some reliability in estimation of time since death.