Blinking would improve your eyesight

Why do we blink instead of blinking each eye individually?

Looking at it fully in terms of evolutionary pressures:

1.1 The whole idea of ​​binocular vision for humans (and some other species) is depth perception. If you suggest continuous, alternate winking, the individual's perception will be seriously affected. The "wink as needed" mechanism (assuming all other visual processes are as they evolved today) would look like constantly switching between binoculars and telescopes while still trying to move forward .

1.2 If you suggest that there is still evolutionary pressure to blink, it is very likely that the evolutionary pressure for coordinated movement / efficient perception that works along with the evolutionary pressure for depth perception is much higher in comparison. (This is especially true if the eye-brain coordination developed before the blinking mechanism, as it does, which explains your point of view on “how we are, not how we got here.” Obviously, fish have an eye- Brain develops coordination, but not blinking)

This link explains the evolutionary pressure for depth perception / stereopsis to an extent https://en.wikipedia.org/wiki/Depth_perception#Survival

2.1 As for the chameleon, the mechanism of winking / rolling eyes could be very closely related to the development of chameleon vision. It is seen as a link for studying the development of binocular vision and stereopsis (depth perception) from monocular vision.

https://en.wikipedia.org/wiki/Chameleon_vision