eye exam props

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eye exam props

Post by Doug Tiedt on 12/2/2017, 11:33 pm

I recall reading here that some folks actually bring in the pistol (with permission) or the slide of their gun at the time
of their eye exam to dial in their prescription for focus on the front sight.  I believe the point of this exercise is for the Dr.
to be able to fit your prescription for perfect focus on the tip of the front sight.  Is that correct?

If so, why is that so much better than say, holding a pencil with a sharp point in front of your fist at the correct distance to
mark the point of focus?  I'm thinking of having my eye doctor create a prescription for me so I can shoot iron sights again,
and would like to know if there is anything wrong with the "pencil tip" approach?

Second question, what do I need to know about ordering a pair of glasses for shooting?  Safety glass to ANSI specs and
what else?  Did you have 2 prescription lenses installed, or was the non shooting eye "blacked out", made cloudy, etc? 
I can understand that having the prescription filled for both eyes allows you the most flexibility to use those glasses for
something else that is at that exact distance (not sure what that might be...).

Thanks in advance,
Doug

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Re: eye exam props

Post by LenV on 12/3/2017, 1:05 am

I brought my air pistol with dot attached one time so I could get the dot round. A pencil tip wouldn't have worked for that. I routinely wear trifocals with the middle lens set so I can see my dash clearly. This also works for front sights when shooting carry pistol or any steel sight basically. For a pair of dedicated shooting glasses for steel sights I use safety glasses with a yellow tint and use bifocals for my left eye with reading and distance lens and set the right eye up with only the middle distance and reading lens. This way I can put my occluder anywhere it feels right and front sight is in focus. With about 80% of the right lens set up to focus on front sight I don't have to push my glasses back on my nose constantly to be aligned perfectly.

Len
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Re: eye exam props

Post by mikemyers on 12/3/2017, 2:53 am

Theoretically, a pencil point is all you need.  Much better to tape a business card with small text on it, at the distance where the front sight is, as they will ask you to read the letters, and then "which is best".  With written letters everyone is satisfied.

Glasses - my last set was made with target prescription in my shooting lens, and a prescription in the other so I can adjust sights, etc. using that eye.


For red dot, many people say to focus on the target, in which case you just need a "distance" prescription.


Lots of ways to do this - I took the easy way out, and got one set for front sight, one handed, another for front sight, two-handed, and a third for red dot (distance).  I got sturdy frames, and large lenses to cover as much of my face as practical.
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Re: eye exam props

Post by jglenn21 on 12/3/2017, 9:26 am

My dad was an optometrist and BE/PPC  shooter for many years.. he always had shooters come in after normal hours and bring their pistol when he ran his own office.( different times). Later he had several Plastic toy guns he fixed up to use when helping shooters. he also would used hardened lenses for those glasses..
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Re: eye exam props

Post by Wobbley on 12/3/2017, 9:53 am

Talking to the optometrist that does all the Randolph shooting glasses prescriptions, he advised that you take your normal distance correction and add .75 diopter (+/- .125 diopter).  

He also advised that putting the front sight in perfect focus might not be the best idea.  You need a balance between the target aiming black and the front sight.  You use the depth of field of the eye to where the front sight can be in “good focus” and the black is still dopistinctive enough.  So the center of the depth of field might be 5-10 yards down range.
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Re: eye exam props

Post by fc60 on 12/3/2017, 11:31 am

Greetings,

My local Optometrist was most helpful.

They make a miniature Snellen card, about 5"x7", for testing eyes for reading.

He cut a rectangular slot in it and slipped it over a yardstick.

I had measured the distance from the end of my nose to the front sight and this value was used on the yardstick.

Then he "spun the wheels" to get the best setting for reading the card.

Cheers,

Dave
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Re: eye exam props

Post by mikemyers on 12/3/2017, 11:44 am

Wobbley wrote:Talking to the optometrist that does all the Randolph shooting glasses prescriptions, he ......... also advised that putting the front sight in perfect focus might not be the best idea.  You need a balance between the target aiming black and the front sight.  You use the depth of field of the eye to where the front sight can be in “good focus” and the black is still dopistinctive enough.  So the center of the depth of field might be 5-10 yards down range.
Depth of field allows other things to be adequately sharp, but only one distance will be in perfect focus, regardless of how bright it is or isn't (you have less depth of field in dim light).

Many people say you need to have absolutely perfect focus on the front sight, so you see every scratch or mark.  If you accept that, then the front sight focus needs to be precise.  I noticed that when my new target glasses are on, I need a different prescription for one-handed or two-handed shooting.  As I recall, the distances are 24" and 30".  I can see both distances adequately with either set of glasses, but the front sight is only perfectly sharp with the proper lenses.  

If it's a black front sight in front of a black bullseye, while that may be a concern, it's why several people here pushed me towards using a sub-six-o'clock hold, so there is "white" in front of my sights.  I'm accepting now that this is a better way, as my one attempt at trying it made a huge difference in my group.  I'll know better when I return to the USA and get back to the range.
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