Question

what happens to potassium levels in the eye after death

Answer 1

Since the earlier attempts, failed to meet the definite postmortem interval, for variable reasons with much success, the postmortem biochemical changes in various body fluids (Blood, serum, cerebrospinal and intraocular fluids) have been tried for the estimation of time of death. Vitreous humour was preferred because it has a large volume, is easily obtainable, usually free from contamination and the changes in its biochemical parameters take place more gradually. Sturner [1]also remarked the frequent "Miraculous escape" of the eye even in the most severe cases...



Vitreous humour was aspirated from 99 eyes of 50 deceased, where exact time of death was known. In case of hospital deaths the cases, where electrolytes or diuretics were given prior to the death, were excluded from the study.
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  Observations 

The vitreous humour potassium concentra­tion in 99 eyes of 50 deceased was estimated at known postmortem interval varying from 30 minutes to 35 hours.

Variation with age & sexy:

No statistical significant variation in vitreous potassium concentration with age and sex was found at any time interval after death.

Variation in potassium concentration between two eyes when vitreous samples were aspirated simultaneously:

The potassium concentration in vitreous humour of the two eyes was found to be almost equal when vitreous samples, in 6 cases, were aspirated simultaneously from both eyes at various postmortem intervals.

Changes related to the time of death:

There was linear rise in vitreous potassium concentration to lengthening postmortem interval as revealed in [Figure - 1]. It was also observed that the vitreous potassium values increased upto 24 hours after death and no significant rise was seen after that period, though this observation cannot be said to be authentic as we had only few cases recorded after 24 hours [Table - 1].

Coefficient of correlation (r):

In order to demonstrate that there was clear relationship between postmortem interval and potassium concentration. Coefficient of correla­tion was calculated (r = 0.985). This indicates that there is almost perfect positive correlation between the postmortem interval and vitreous potassium concentration, so the postmortem interval can be .