Eye recalibrates during blinking

It sounds like nothing new to anyone who have ever noticed active focus happening after blink, but hey, now it’s scientifically proven :slight_smile: Well, not active focus, because they did not measured visual acuity (with their setting it would be impossible I think), but rather eye movement. But I think it’s still relevant. I think there is a high chance that it’s the same trigger and maybe even same mechanism as what happens during AF.
Also they found some interesting visual cortex mechanism: when you move an object during blink, the eye moves accordingly, but the conscious mind does not acknowledge it. If you “simulate” blink and do the same movement, the conscious mind notices it.

Highlights

  • Displacements of a visual target during eye blinks can go unnoticed

  • Eye movements nevertheless anticipate these unseen target displacements

  • Visual signals recalibrate eye gaze position across eye blinks

Full paper:
https://www.cell.com/current-biology/fulltext/S0960-9822(16)31509-3

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very interesting study:)

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Jumping to conclusions? I experience considerable clearing (active focus) without any intervening blinks, so this is not due to the recalibration mechanism of a blink.

What I found fascinating is the rapid learning by the visual cortex which enables shifts of gaze with the eyes closed after only a few experiences of this happening in the same direction, and the fact that this effect is also soon lost.

It might also be relevant in that a paucity of blinks may lead to visual strain due to the lack of the recalibration mechanism during a blink. Blame the screens

I’ve never said that active focus occurs exclusively at blink. I’ve only said that blinking recalibrates the eye which I think (that’s my conclusion) triggers active focus too. It’s obvious that blinking is not neccessary for active focus.

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And I didn’t say that you said that. :smile: I was just suggesting that we should not rush to see a causal relationship between the recalibration during blinking and AF. The slightly better vision after blinking may be due to other factors - including re-moistening the eye and clearing dust etc. from the surface. Add to this my own experience that my vision sometimes deteriorates after a blink, especially on the 6m Snellen, and it takes unblinking time to get back the clarity.

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I’ve seen that phenomenon as well.

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Some interesting quotes:

“Simulated blinks did not lead to anticipatory eye movements to the target position, even when they were temporally cued or actively triggered by the observer.”

You can’t fake it, it has to be natural??

“Real eye blinks are necessary, indicating that in addition to the visual changes before and after the blink, an oculomotor signal is required to trigger this form of gaze adaptation.”

I’m really not across all the scientific jargon. But ‘gaze adaptation’ sounds similar to ‘accomodation’. Accomodation is, to my knowledge, the ability for the eye to refocus, and tentatively could be active focus. I dunno if this is the same thing as ‘gaze adaptation…’

My vision can change either way after a blink while looking at the 6m Snellen, so I guess my eyes recalibrate the convergence / divergence, sometimes correctly, sometimes incorrectly.

This refers to tracking a moving object with the eyes and not to accommodation. As the brain has learned from recent past experiences that the object of focus has moved in the same direction a few times, it anticipates the next movement during the blink. This would make sense in ‘real life’ vision when tracking the flight of a bird, for example, so that after a natural blink one does not have to adjust the direction of gaze too much to continue tracking the bird. :dove: This anticipatory move is soon dropped when the bird stops moving, or starts moving in a different direction. Probably very important when hunting for food.

I knew that we have a massive long-term visual memory, but did not know that we have such a neat short-term visual memory as well. :smile:

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By faking it they mean that blinks were simulated with shutter glasses, without the subject was not actually blinking. The only implication is that it’s not the brightness change and / or visual input absence which triggers this process.

For the “gaza adaptation” see @Ursa’s comment, it has nothing to do with accommodation.

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My issue is when I’m at my active focus limit, blinking will partially disengage active focus and I have to “re-engage” it. I’m now better at holding AF through a blink, but it’s still challenging at the limit.

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