Find the Odd Disk

What stood out a lot in this exercise is that when looking at, versus near a disc, its luminance (or maybe the color as well) is perceived as changing. Almost the same i have when staring at not too bright stars, they seem to disappear when staring directly on them.

And related, I once had an 'eye migrane'. During that half an hour, the figures of a clock disappeared the moment i looked at them.

I'm curious how the eye migraine is related. I had one many, many years ago. It was a smallish (palm at arm's length) oval in the center of my vision that looked like snow on an analog TV, accompanied by a feeling of overwhelmed by all the colors of the products on the shelves (I was in a grocery). It stuck around for about half an hour for me as well.

I've also had eye floaters which cause things to distort and can be hard to see through. For about 6 months I had a large one in the center of my left eye vision, which was a bit scary when I discovered I might not see a car reflected in my wing mirror.

Similar experience. What surprised me: sometimes the odd-one-out was really quick/easy to see, and other times it took much longer & I thought "at the end, they'll say all disks were the same color".

Got 14/20

I’ve had visual migraines ever since I started training hard with weights. Played sports in High School and never had one, but suddenly I’m doing CrossFit in my late 30s and an hour after a workout I get these sparkly jagged lines in my vision (both eyes!). It took a while to even be able to describe them, let alone figure out what they were. Thankfully there’s no pain and they clear up after a while, but I have noticed since this all started that I’m also a bit more sensitive to screen brightness. That HDR emoji article from the other day was kind of triggering.

Sounds like symptoms of impending retinal detachment - ex discussion https://www.reddit.com/r/myopia/comments/o7rhi3/retinal_deta...

I had visual migraines for years, and was thankful they weren't full-blown... until I started getting headaches that lasted 18+ hours (pretty sure they're migraines). Now I'm just thankful I don't have multi-day-long ones.

I experienced this too. IIRC the brightness-sensitive rod cells are more concentrated in your peripheral vision while your central vision has more colour-sensitive cone cells. This makes the centre of your vision less sensitive to dim objects, so you can see them only while looking indirectly (and they "disappear" when staring at them)

Another related effect is flickering of badly designed lighting only in my peripheral vision. When looking directly at the lights they look fine, but when the lights are in my peripheral vision they appear to flash distractingly. I think the peripheral vision is optimised to detect fast changes/movements. At least, that makes sense based on evolution.

The characteristic ‘jagged lines’ of aura is not at all related to the characteristic visual flashes of retinal detachment which an entirely different pathophysiology. Given that the advent of the flashes are new and related to exertion however it wouldn’t be unreasonable for the OP to keep a log of onset and duration and consider neurologist referral if they were to become more common with consideration for screening imaging as there are certain conditions related to exertion that can trigger aura

The symptoms you mention read like scintillating scotoma: https://en.m.wikipedia.org/wiki/Scintillating_scotoma

I've had it happen many times and it's usually followed by a regular headache. Quite terrifying the first few times it happened to me. Felt like I was losing my sight.

Spending the whole night gaming when I was younger would sometimes trigger it in the morning. Thanks to not having any more time for that, it hasn't happened in years.

This is referred to as 'Averted Vision'

https://en.m.wikipedia.org/wiki/Averted_vision

For some of the easier ones, I was surprised by how aggressively my brain was making what seemed like "close" colors stand out. Like it was mentally "highlighting" the odd one out. I thought that was cool, but eventually the later ones were hard enough that the effect went away, and I was much less confident in my choices, and I got 3 mistakes, all in the last five rounds.

The way your brain manipulates your vision 24/7, with no way to get around that, is truly crazy to me. There's all sorts of effects in your visual system like edge detection and certain types of stimulus suppression that it's crazy we even feel like reality is coherent.

I doubt it. I’ve described the issue to multiple eye doctors, none of whom mentioned this. It’s literally a psychedelic looking jagged line in my vision (which I can see with either of my eyes closed, superimposed over my vision). I’d think if it were an eye issue directly it only affect one or the other (or if both, it would be discernible which one is flaring up).

During an episode I usually first notice it as it is entering my focal region and interfering with reading. Then it sort of moves across my field of vision until it’s in my peripheral, and then goes away altogether.

The flickering i see as well when looking near my ali express outdoor LED light strip, from the corner of my eyes. The sub-components of the PWM seem to emerge as well.

What i saw during the eye migraine when closing my eyes was jittery jagged short bright lines, together forming a half moon. When i looked that up on the internet back then, it was explained as symptoms of 'eye migraine' and i believe it is an inflammation of the visual nerve. The disappearing numbers on the clock were quite scary, that is why i remember.

Indeed the animated jitter in the meadow shown on Wikipedia is close to what i remember seeing. 'Cortical spreading depression' is said to be the cause.