Back in the late 60's-70's my father worked in a small hospice in Adelaide, Australia.
I would frequently tag along as a teenager to help out with small things like washing, cleaning, getting patients water, etc.
This only ever, in mine and his experiences, occurred among individuals with quite dark brown eyes, going blue towards death.
This is due to the body's tendency to stop producing melanin near death, for reasons unknown to me.
- i'll explain as best I can, quickly.
Melanin (or a lack of) creates the pigmentation in your eye. Essentially;
Brown = high amnt. of melanin
Green = mid-high amnt. of melanin
Hazel = low-mid amnt. of melanin
Blue = very low/no melanin
It seems the lack of melanin production near death is the cause for such a rapid change of colour.
If any of you fish, next time you catch one you can see this for yourself. Note the eye colour of the fish when alive. Once dead, after some minutes,
the eye will appear noticeably paler and light blue.
Sorry for the long response, I hope your mum is okay.
I, by no means am knowledgable regarding medicine, biology, etc. This is based on my experiences 35 years ago, and what my father told me at the
time, which likely isn't considered true anymore. If i'm incorrect, let me know. Thanks.
edit on 8-7-2016 by ColorisSanguinum because: