Re: [Phys-l] Baseball

[Bernard Cleyet <bernardcleyet@redshift.com>]

Yes, they are stenopaeic glasses.  A European friend showed me his 
lorgnette one back in the 70's.

You may try it.  If you are "naturally" emetropic borrow some "weak" 
glasses, say, one or two D + or -, otherwise remove your glasses.   
Punch a small hole about one mm D in a card and note the improvement in 
visual acuity.  I just tried it.  Or use callipers to make variable 
slit:  noticeable fringing at about 0.4, and still much improvement at 2 
mm indoors.  I didn't notice my hyperopia until pupils dilated by 
optometrist back at about age 60.

bc, former IOL manufacturer's consultant



Anthony Lapinski wrote:

> Do pinhole glasses work on the same principle? I hear they're supposed to
> "help your vision."
>
> Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu> writes:
>  
>
> > The technical term is stenopaeia. 
> > Improvement is not limited to myopics. 
> > A letter in a recent TPT discussed this w/o giving the optometric / 
> > ophthalmic term.
> > There are several competing effect regarding vision in stenopaeia.  
> > Obviously intensity is reduced, also diffraction will reduce 
> > visibility.  Squinting is, therefore, not useful with low ambient 
> > illumination.
> >
> > In a thread on the camera obscura, I suggested the exercise:  Determine 
> > the optimum F/.
> >
> > bc
> >
> >
> >
> > Dennis Erickson wrote:
> >
> >    
> >
> > > Squinting can make the image sharper (clearer).  For a near sighted  
> > > person it helps because it increases the depth of field(in focus  
> > > distances)
> > >
> > >
> > > Dennis Erickson
> > > WA9FBC
> > >
> > > Chicago Sidewalk Astronomy Club
> > > Chicago Section--International Dark-Sky Assn.
> > > http://www.sidewalk-astronomy-club.com/chicago
> > > http://www.darksky.org
> > >
> > > Keep your Eye on the Sky!
> > >
> > >
> > > On Oct 19, 2006, at 11:48 PM, JMGreen wrote:
> > >
> > >
> > >
> > >      
> > >
> > > > There is something I don't understand re baseball pitchers:
> > > >
> > > > Some pitchers -- but not all -- lean over and squint at the catcher
> > > > when taking a signal -- Why do they do this?
> > > >
> > > > Are they trying to get a bit lower or a bit closer to the catcher  --
> > > > perhaps to improve vision in some way?
> > > >
> > > > Is there some principle of optics that I don't understand?
> > > >
> > > > Or is the pitcher just trying to look silly?
> > > >
> > > > Jim
> > > >
> > > >
> > > > J M Green
> > > > Email:  MailTo:JMGreen@sisna.com
> > > > WWW: HTTP://users.sisna.com/JMGreen
> > > >
> > > > _______________________________________________
> > > > Forum for Physics Educators
> > > > Phys-l@carnot.physics.buffalo.edu
> > > > https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
> > > >   
> > > >
> > > >        
> > > _______________________________________________
> > > Forum for Physics Educators
> > > Phys-l@carnot.physics.buffalo.edu
> > > https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
> > >
> > >
> > >
> > >
> > >      
> > _______________________________________________
> > Forum for Physics Educators
> > Phys-l@carnot.physics.buffalo.edu
> > https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
> >    
>
>
> _______________________________________________
> Forum for Physics Educators
> Phys-l@carnot.physics.buffalo.edu
> https://carnot.physics.buffalo.edu/mailman/listinfo/phys-l
>
>
>