Author Topic: Focal distance shortens when I'm in a hurry  (Read 4548 times)

Offline johnlink

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Focal distance shortens when I'm in a hurry
« on: April 07, 2013, 09:05:37 AM »
The other day I had just 30 minutes available for a bike ride. I had to be back in time for an appointment, so I had no leeway. After I finished my ride I realized that I had neglected to look into the far distance as I've been doing on my rides for the last few weeks. Instead I kept my gaze just far enough in front of me to deal with the hazards of riding in Manhattan streets and on the bike path along the Hudson. I think it was the hurry that provoked the shortening of my gaze.

Has anyone else noticed anything similar?

Offline OtisBrown

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Re: Focal distance shortens when I'm in a hurry
« Reply #1 on: April 07, 2013, 10:23:01 AM »
Hi John,
I don't know if this case was similar - but when I was wearing under-prescribed contact lenses, I would see my vision improve by about one diopter after about an hour playing tennis.  This proved to me that improvement is possible.  Keep up you exploration and efforts - it is worth the effort.

The other day I had just 30 minutes available for a bike ride. I had to be back in time for an appointment, so I had no leeway. After I finished my ride I realized that I had neglected to look into the far distance as I've been doing on my rides for the last few weeks. Instead I kept my gaze just far enough in front of me to deal with the hazards of riding in Manhattan streets and on the bike path along the Hudson. I think it was the hurry that provoked the shortening of my gaze.

Has anyone else noticed anything similar?

Offline johnlink

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Re: Focal distance shortens when I'm in a hurry
« Reply #2 on: April 07, 2013, 04:10:44 PM »
Hi John,
I don't know if this case was similar - but when I was wearing under-prescribed contact lenses, I would see my vision improve by about one diopter after about an hour playing tennis.

Otis, that does not sound similar to the phenomenon I described. You described an improvement through an activity while using under-prescribed contact lenses, but I described a negative change in my visual habits due to an attitude I had during any activity.

Offline peterg

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Re: Focal distance shortens when I'm in a hurry
« Reply #3 on: April 08, 2013, 07:43:24 AM »
The other day I had just 30 minutes available for a bike ride. I had to be back in time for an appointment, so I had no leeway. After I finished my ride I realized that I had neglected to look into the far distance as I've been doing on my rides for the last few weeks. Instead I kept my gaze just far enough in front of me to deal with the hazards of riding in Manhattan streets and on the bike path along the Hudson. I think it was the hurry that provoked the shortening of my gaze.

Has anyone else noticed anything similar?

Hi John,

I believe this matches with what I have been trying to explain as an issue. It is rather difficult to practise some of those habits that we believe will help us when we are under pressure.  In my opinion, you've described the same issue I face with trying to stay just inside the edge of blur.  When I require high focus on the task at hand due to work demands, or when my mind wanders, I seem to pull in from the optimal reading distance.

I think for these reasons, most child based studies with plus lenses, vision therapy, bates, or any combination show insignificant benefit if any at all.

There have been some other studies with older military school college students and plus lenses, which is the target age group Otis is interested in. I have no idea how that study was conducted.  But it also showed no benefit (statistically). It's my opinion, that if no guidance is given, if the discipline required is not explained (i.e. your riding deire of attempting to look further out, my reading desire of wanting to stay just inside the blur), then the outcomes of the studies will never look promising.  I must admit that I have only superficially understood how many of these studies, so you will do well to read and understand them.

Peter


Offline johnlink

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Re: Focal distance shortens when I'm in a hurry
« Reply #4 on: April 08, 2013, 10:07:41 AM »
The other day I had just 30 minutes available for a bike ride. I had to be back in time for an appointment, so I had no leeway. After I finished my ride I realized that I had neglected to look into the far distance as I've been doing on my rides for the last few weeks. Instead I kept my gaze just far enough in front of me to deal with the hazards of riding in Manhattan streets and on the bike path along the Hudson. I think it was the hurry that provoked the shortening of my gaze.

Has anyone else noticed anything similar?

Hi John,

I believe this matches with what I have been trying to explain as an issue. It is rather difficult to practise some of those habits that we believe will help us when we are under pressure.

I believe that's universal. During my Feldenkrais training my teacher said that it was important to separate learning and performance.

Quote
In my opinion, you've described the same issue I face with trying to stay just inside the edge of blur.  When I require high focus on the task at hand due to work demands, or when my mind wanders, I seem to pull in from the optimal reading distance.

So now that we have observed ourselves shortening our focal length when under pressure we can devote some attention to expanding our awareness in such situations, and cut ourselves some slack when we revert to our habitual shortening.

Quote

I think for these reasons, most child based studies with plus lenses, vision therapy, bates, or any combination show insignificant benefit if any at all.

There have been some other studies with older military school college students and plus lenses, which is the target age group Otis is interested in. I have no idea how that study was conducted.  But it also showed no benefit (statistically). It's my opinion, that if no guidance is given, if the discipline required is not explained (i.e. your riding deire of attempting to look further out, my reading desire of wanting to stay just inside the blur), then the outcomes of the studies will never look promising.

That sounds right. If the subject of the experiment does not engage his awareness and intention appropriately then I expect any positive results to be minimal.

Offline jansen

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Re: Focal distance shortens when I'm in a hurry
« Reply #5 on: April 08, 2013, 06:34:02 PM »
I've experienced something similar when I get focused onto pretty much anything. Often, it is "staring" or looking forwards too much, and not focusing on different objects. I understand that we must focus near when riding a bike in order to prevent injuries/accidents, but we can try to switch focus from one object to another every once in a while to break up the staring. In city scenes, there should be plenty of different objects to focus on.

Offline johnlink

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Re: Focal distance shortens when I'm in a hurry
« Reply #6 on: April 10, 2013, 08:12:09 AM »
I've experienced something similar when I get focused onto pretty much anything. Often, it is "staring" or looking forwards too much, and not focusing on different objects. I understand that we must focus near when riding a bike in order to prevent injuries/accidents, but we can try to switch focus from one object to another every once in a while to break up the staring. In city scenes, there should be plenty of different objects to focus on.

I consider staring while riding a bike or driving a car to be very dangerous. I keep my eyes moving all the time so that I can be aware of everything around me, including behind me. When I took driver's ed in high school the teacher told us to be constantly scanning, including checking the mirrors.

I see that seeing habit number 3 on the UPS site repeats what my teacher told me: http://www.community.ups.com/Safety/Safe+Driving+Tips

Offline OtisBrown

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Re: Focal distance shortens when I'm in a hurry
« Reply #7 on: April 11, 2013, 05:00:22 PM »
Hi John,

Yes your focal distance does change - and can result in a changed prescription.  I am curious - can you provide your current prescription - to establish a base-line for your expected improvement?

Thanks!


I've experienced something similar when I get focused onto pretty much anything. Often, it is "staring" or looking forwards too much, and not focusing on different objects. I understand that we must focus near when riding a bike in order to prevent injuries/accidents, but we can try to switch focus from one object to another every once in a while to break up the staring. In city scenes, there should be plenty of different objects to focus on.

I consider staring while riding a bike or driving a car to be very dangerous. I keep my eyes moving all the time so that I can be aware of everything around me, including behind me. When I took driver's ed in high school the teacher told us to be constantly scanning, including checking the mirrors.

I see that seeing habit number 3 on the UPS site repeats what my teacher told me: http://www.community.ups.com/Safety/Safe+Driving+Tips

Offline johnlink

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Re: Focal distance shortens when I'm in a hurry
« Reply #8 on: April 11, 2013, 05:33:10 PM »
Yes your focal distance does change - and can result in a changed prescription.  I am curious - can you provide your current prescription - to establish a base-line for your expected improvement?

Otis, I'm afraid you've missed my point, which was that when I am in hurry I tend to not look so far into the distance even though my vision in the distance is perfectly clear (with my contact lenses). That's what I meant by my focal distance shortening.

Offline Todd Becker

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Re: Focal distance shortens when I'm in a hurry
« Reply #9 on: April 11, 2013, 06:06:14 PM »
The other day I had just 30 minutes available for a bike ride. I had to be back in time for an appointment, so I had no leeway. After I finished my ride I realized that I had neglected to look into the far distance as I've been doing on my rides for the last few weeks. Instead I kept my gaze just far enough in front of me to deal with the hazards of riding in Manhattan streets and on the bike path along the Hudson. I think it was the hurry that provoked the shortening of my gaze.

Has anyone else noticed anything similar?

John,

What you are observing may be the simple (and well-established) fact that activation of the sympathetic nervous system (associated with the "fight-or-flight" response and stress hormones like adrenaline, norepinephrine and cortisol) result in narrowing of the visual field and focal range, whereas the parasympathetic nervous system (associated with relaxation) has the opposite effect.

Here are a few interesting references that bear on this:
http://www.iovs.org/content/50/1/114.long
http://www.hfrg.org/storage/pdf/BATF-stress%20brief.pdf
http://journals.lww.com/jonmd/Citation/1944/05000/The_Role_of_the_Autonomic_Nervous_System_in.37.aspx

This accords with our common experience that we often tend to hyper-focus when under stress. It's likely a survival response that has evolutionary advantage  in helping primates and other mammals deal with what is right in front of them in tense or urgent situations.  When we are more relaxed and have the luxury of more time, we can benefit by taking in the wider scene.

I think this explanation coheres with both common experience and science.

Todd

Offline johnlink

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Re: Focal distance shortens when I'm in a hurry
« Reply #10 on: April 12, 2013, 12:43:49 PM »
Todd, thank you for the references and your thoughts on this matter.