How does the eye know when the image is in focus? There is distance measuring device, only light entering the eye. No outer feedback to be sure that focus is in fact focus not something the eye think is focus.

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Thank you all for your respons and upvotes.

I can now see and focus on the answer of my question 🙂

In: 3993

Answer 1

There is the possibility that we have a distance measuring device but we have not found it yet. But, at the current level of knowledge it would be our brain adjusting for distance. It is not something I would subscribe to, and I would encourage anyone thinking about this to maybe find that measuring device.
Obviously that would require your eyes sending something out and recieving the reflected signal, instead of only recieving. If eyes are only recieving then there is only your brain to do the focusing. However, I haven’t found myself in a situation where I could consciously control the focusing. I can control it by lookin at things which are at different distances but I could never focus on things by thinking “I want to focus on that right now”. I look at it, and my focus shifts. That isn’t really a conscious mechanism. But make of that what you want.