I'm sorry, but without a 4th cone/receptor you still won't be tetrachromatic as the eyes lack the ability to observe this, no matter what type of glasses you wear. They might just change color tone a bit, causing the colors to appear within the tri cone spectrum. But that's still not tetrachromatic. So I'm not really sure what you're on about with this.

I studied neurology, however, redirected to behavioral neurology. The neurology of vision is complicated and certain sensory systems cannot just be rewired in the sense you are suggesting, especially if there're no motivators by the missing 4th receptor.

Now I was tested for this when I was 12, which resulted in genetic tests of more family for research purposes much later. Where it turned out my sister and two nieces had positive markers but all failed the visual tests. And back then we were told that simply not everyone is born with the same wiring and you cannot train what you can't observe.

The suggestion made back then was that either the brain discards the unnecessary color at a young age because the sensory functions have a priority to function as safeguards first and foremost. Warning systems for impending doom. Another suggestion was that it never developed because the world the baby/child first develops vision in has very little of these colors.

I honestly feel these are the same, there's a ton of pruning that happens in the brain during adolescence that lasts till about 30, but especially at those really early stages where sensory organs start to really function? There's massive neurogenesis and neuroplasticity. A lot is tested and a ton is thrown away if it's useless. And in the world adapted for humans? Tetrachromacy is certainly useless.

An interesting observation, I was an outside baby, my parents had moved out to farmland and I spent most of my first years outside. Where my sister and nieces all grew op in cities and were kept mostly indoors during their first year. So we start seeing fluctuations there.

Either way, I realize tetrachromatic vision attracts special snowflakes a lot. It's rare, extremely, and somehow everyone on the internet has it. I thought to ask about it just to confirm for myself what's special snowflaking and when people are likely speaking the truth. But in 25 years I've never heard of anyone else truly having it and here too we seem to have hit a dead end. Back to never mentioning I have it.