Yes, reading this article I also remembered having no problem as a kid who grew up next to the beach. As an adult many times removed from that life, I now need goggles when I go swimming. It's a shame the body loses that adaption so easily.
I thought my memories of seeing in the water were false. I used to swim in deep crevasses in the river by my home and look for glimpses of trout and steelhead. I could dive down and get crayfish after spotting them from fairly high up. I remember needing to equalize many times and my body would lose buoyancy. Sometimes I'd lay on the sand or rocks and those are my most vivid memories of seeing under water. The algae on the rocks would be swaying, sunlight refracting all over, and the sound was nothing but a gentle, deep, soothing vibration of the water tumbling over stones.
I recall my vision being far from perfect past 6 or 7 feet, but still pretty usable.
These days I need a low volume mask and contacts if I want to see anything in the water.
It's an adaptation? Huh, never thought about it. I would go swimming in the sea when I was a kid without goggles, could see everything clearly. Nowadays it hurts opening my eyes underwater, I assumed it was just polluted as hell (by all reports it is)...
