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Question Short-term change in vision- possible causes?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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New Member
Feb 4, 2022
I've been freediving for a year+ now (certified) and had a strange experience recently - my instructor & doctor both had never heard of it. I typically dive to 10/12m and hang/swim at that depth, although I have previously gone to 19m.

I was line diving to 20m 3x (with long surface intervals) and equalizing my ears/mask (I think fully). Ten minutes later, while swimming at the surface my vision changed - there was a red/pink tint to everything (e.g the clouds were reddish etc.) I took off my mask and within a minute returned to normal colors. I took a break but a week later the same vision change happened after repetitive dives to just 7m, and I felt faint/woozy for hours after. No change after just wearing my mask at the surface with no depth.

Any ideas what this could be? Many thanks in advance!
Ps. My eyes were white and not at all blood shot after each dive.
Very interesting, off the top of my head I can think of a few possibilities:
1. seizure - can present with any focal neurological sign, like the vision change you mentioned. Would tend to reoccur exactly the same with the same provocation.
2. optic migraine w/ transient tritanopia - basically a blue/yellow color blindness that causes everything to look red.
3. some medications like in TB and anti-psychotic treatments can cause strange visual changes.
I had a similar experience one time. I was diving in a quarry down to 30 meters. When I was almost at the bottom i had a very rapid change in vision. I later figured out what happened. As I was clearing my ears, I was pinching my nose so tight that I wasn't allowing any air into my mask. I dive with an Aqua Sphere mask which is low volume with plastic lenses, so it gives under pressure. As I dove deeper and deeper the air inside the mask compressed (mask squeeze). At about 30 meters I felt a slight "pop" in my head and my visioin blurred. Freaked me out, but I was fine. Took me a while to figure it out. I did get a a little bloodshot in one eye, but no lasting change. I think the "pop" was actaully air escaping my nose and equalizing the mask.

So, check it out next time you dive and be sure to blow a little air through your nose into your mask to equalize the pressure there as well. Especially if you have a mask with a glass lens.
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