<p>Yes, but you would have to modify the optic array in 2 ways:</p>
<p>(1) Accommodation: if your eye accommodates for 20m (top row), an object at 1m will be out of focus (middle row). Thus for accommodation to be identical to that of an object at 20m, you need to add a lens in front of the eye (bottom row).</p>
<p><a href="https://i.sstatic.net/hWtz5.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/hWtz5.png" alt="enter image description here" /></a></p>
<p>(2) Vergence: if you look at the object binocularly, your eyes will cross (vergence angle) at 20m. If the object is at 1m that angle will be different. Therefore you need to place prisms such that the resulting vergence angle will match that of an object at 20m. This is essentially a stereoscope.</p>
<p><a href="https://i.sstatic.net/zDvVg.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/zDvVg.png" alt="enter image description here" /></a></p>
<p>So in order to correctly simulate an object at 20m, you need to add both a spherical lens to change the accomodation, and prisms to change vergence. Of course if the observer sees the object monocularly you do not need the prisms. Finally if your observer moves then the parallax of the object also needs to match that of an object at 20m, so you'll need to physically move the object accordingly.</p>

CC BY-SA 4.0
2022-04-28T16:09:27.303Z
2022-04-28T16:09:27.303Z
4s2S8k0t4Pxn
<p>Is it possible to use a clever combination of lenses and mirrors placed between your eye and a screen 1m away from you to make the eye react to the screen as if it were 20m away from you?</p>
<p>What I'm asking is whether it's possible to, using lenses, modify the light emanating from a screen physically placed 1 m away from the eyes so that the eyes behave as if the screen were 20m away. This isn't a pure physics/engineering question, nor is it a claim that video games cause myopia.</p>

CC BY-SA 4.0
2021-11-07T03:36:53.153Z
There's a mix of questions and assumptions here but it really seems more like a question of physics and engineering rather than medicine or biology.
Bryan Krause
CC BY-SA 4.0
2021-11-07T04:31:56.393Z
It is more about physics and engineering until you get to the part about the risk of developing myopia, and then it becomes a medical question with no prior research. Does playing video games increase the risk of myopia? I'm skeptical that it does. Welcome to MedSci.SE. We require questions here to demonstrate some degree of prior research, so please [edit] your question to address the underlying question of whether myopia is a real risk or not.
Carey Gregory
CC BY-SA 4.0
2021-11-08T04:24:49.680Z
I think both readings have misread my question, so I've simplified it. I don't know whether screens cause myopia (or not). What I'm asking is whether it's possible to, using lenses, modify the light emanating from a screen  physically placed 1 m away from the eyes so that the eyes behave as if the screen were 20m away. This isn't a pure physics/engineering question, nor is it a claim that video games cause myopia. If this isn't the stackexchange, then where should I post this?
abelian
CC BY-SA 4.0
2021-11-08T05:06:54.443Z
Thank you for the clarification. It's clearly a physics and engineering question, but it also involves a human component. I don't know what it means to say your eyes behave as if the screen is 20m away when it's actually 1m away. Your eyes don't have range finders. It's your brain deciding what to focus on, and visual perception is squarely under the umbrella of Psychology & Neuroscience, so that's probably the best place for this question. I am migrating it.
Carey Gregory
CC BY-SA 4.0
2021-11-10T01:43:00.697Z
Is this not basically what virtual reality glasses do?
Ray Butterworth
CC BY-SA 4.0
2021-11-11T20:24:14.003Z
Thanks Carey! What I mean is whether, if we compare the physical state of the eye when it's looking at an object physically 20m away, vs the physical state of the eye looking at an object physically 1m away, whether it's possible to use optics to make the latter like the former. Thanks for helping to move the question to its new home!
abelian
<perception><sensory-perception><optical-illusion>
Mirrors/optics and physical adaptation of the eye
abelian
# Mirrors/optics and physical adaptation of the eye

(Asked by: username_0 on 2021-11-07)

Is it possible to use a clever combination of lenses and mirrors placed between your eye and a screen 1m away from you to make the eye react to the screen as if it were 20m away from you?

What I'm asking is whether it's possible to, using lenses, modify the light emanating from a screen physically placed 1 m away from the eyes so that the eyes behave as if the screen were 20m away. This isn't a pure physics/engineering question, nor is it a claim that video games cause myopia.

**Tags:** perception, sensory-perception, optical-illusion

> **Comments:**
> **username_1**: There's a mix of questions and assumptions here but it really seems more like a question of physics and engineering rather than medicine or biology.  
> **username_2**: It is more about physics and engineering until you get to the part about the risk of developing myopia, and then it becomes a medical question with no prior research. Does playing video games increase the risk of myopia? I'm skeptical that it does. Welcome to MedSci.SE. We require questions here to demonstrate some degree of prior research, so please [edit] your question to address the underlying question of whether myopia is a real risk or not.  
> **username_0**: I think both readings have misread my question, so I've simplified it. I don't know whether screens cause myopia (or not). What I'm asking is whether it's possible to, using lenses, modify the light emanating from a screen  physically placed 1 m away from the eyes so that the eyes behave as if the screen were 20m away. This isn't a pure physics/engineering question, nor is it a claim that video games cause myopia. If this isn't the stackexchange, then where should I post this?  
> **username_2**: Thank you for the clarification. It's clearly a physics and engineering question, but it also involves a human component. I don't know what it means to say your eyes behave as if the screen is 20m away when it's actually 1m away. Your eyes don't have range finders. It's your brain deciding what to focus on, and visual perception is squarely under the umbrella of Psychology & Neuroscience, so that's probably the best place for this question. I am migrating it.  
> **username_3**: Is this not basically what virtual reality glasses do?  
> **username_0**: Thanks Carey! What I mean is whether, if we compare the physical state of the eye when it's looking at an object physically 20m away, vs the physical state of the eye looking at an object physically 1m away, whether it's possible to use optics to make the latter like the former. Thanks for helping to move the question to its new home!  

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## 1 answers

### Answer by username_4 on 2022-04-28. Score: -1

Yes, but you would have to modify the optic array in 2 ways:

(1) Accommodation: if your eye accommodates for 20m (top row), an object at 1m will be out of focus (middle row). Thus for accommodation to be identical to that of an object at 20m, you need to add a lens in front of the eye (bottom row).

[![enter image description here](https://i.sstatic.net/hWtz5.png)](https://i.sstatic.net/hWtz5.png)

(2) Vergence: if you look at the object binocularly, your eyes will cross (vergence angle) at 20m. If the object is at 1m that angle will be different. Therefore you need to place prisms such that the resulting vergence angle will match that of an object at 20m. This is essentially a stereoscope.

[![enter image description here](https://i.sstatic.net/zDvVg.png)](https://i.sstatic.net/zDvVg.png)

So in order to correctly simulate an object at 20m, you need to add both a spherical lens to change the accomodation, and prisms to change vergence. Of course if the observer sees the object monocularly you do not need the prisms. Finally if your observer moves then the parallax of the object also needs to match that of an object at 20m, so you'll need to physically move the object accordingly.


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