Corrective lenses and zero

Status
Not open for further replies.
A

Andrew Wyatt

Member
Joined
Dec 25, 2002
Messages
4,472
Location
Bakersfield, California
I just recently got two pair of corrective glasses, one polarized set of ray bans, and one pair of clear lens glasses. I notized an almost magical improvement in my shooting with my garand while wearing the ray bans. I haven't shot wearing my clear lenses yet. which brings me to my question.


do you have a point of impact shift when wearing different pairs of glasses?
 
In theory no - sights are sights. However - the clarity of vision naturally affects the sight picture and so sometimes it could be that a ''struggle'' picture could make for a consistent error that could be perceived as a difference between glasses or no glasses.

IMO from a purely optical standpoint - no change expected.
 
Interesting that I am going through the same thing. I have worn contacts for about 25 years, and am now needing bifocals (yea, P95, I'm and OF, just turned 47... :D ). I am trying to decide if I want to keep my contacts and wear reading glasses, or go to bifocal glasses. I'll keep an eye on this one...
 
yea, P95, I'm and OF, just turned 47...
Click to expand...
Hahha - well ''son'' - sorry but you ain't there yet - OF that is! :D It'll come tho - fear not! :neener:

I don't really know which would or will suit you better - bifocals or progressives are darned convenient and - any of us shooting must have some glasses on anyways. I again tho cannot foresee a genuine optical reason for any POI change - it would only be IMO as a result of some change of sights perception. Only possible exception I can think of might be a gross change in axial correction compared with the ''before'' stage - that just maybe could affect results.

Need Mr Tetnanger on this - he is I believe our resident occulist!!
 
I wore corrective lenses for over 15 years, and just got LASIK surgery. I never thought I had problems with sight alignment before, but I have noticed my groups improving. I'm not sure why, but my pistol groups particularly have improved. I think as said before, it has to do with the struggle of looking through the lense and the sights, etc.

However, I did notice it took a little getting used to anytime I changed style of frames I wore before. Took maybe a week for my shooting to get back to the "norm."
 
I have astigmatism, and that caused a consistant point of impact shift.


I guess i should shoot my guns without the corrective lenses, and with both sets of glasses to see how far off things get.
 
when they make your lenses they have to set the 'center' of the lens. I don't know the correct term. This is something I've had some doctors make a big deal about, and others never mention it. But it's the point of the lens that focuses the light into the center of your eye.

I, too, have astigmatism, so maybe it has to do with that. But, my point is, that this 'center' will vary with different lenses. So, it will change your focus and therefore your point of impact. You still hold your head the same way, and look at the sights the same way, but your eye is looking through a different point of focus on each different lens.

I could be completely wrong on this, but I think I've got the gist of it...
 
Kami - yeah - this is what had occurred to me re axial corrections - my statement re no effect was, on reflection, aimed at merely pure dioptric correction factors.

Again - call for Mr Tetnanger! He should be able to give us the real skinny here.
 
P95:

I would expect that any use of a optical sight that is not 100% corrected for parallax will see a shift when using glasses.


The only way to avoid this would be to have the optical center of the glasses perfectly in line with the optical center of your scope: an unlikely circumstance.

It shouldn't affect anything if your parallax is dialed out.
 
I had lasik surgery 2 years ago. Fixed sighted handguns that I knew shot center before the surgery now shoot high left. @ 50 ft. I'm seeing about a 3" displacement of groups. I still have some residual astigmatism so that is a posible source of my POI change.

It seems to me that throught the years as my eyes and glasses changed my handguns POI also changed some. I never thought this was unusual as I also see a POI change between indoor range shooting and outdoor natural light shooting.
 
I was lucky enough to find an optometrist who not only listened to what I wanted to SEE but came out on the range to help me with various lens combinations to determine what actually worked for high power rifle. Two things were critical and took some trial-and error. One was to grind the optical center to the part of the lens that I actually looked through in offhand/sitting/prone; The other was to select a diopter rating that gave me decent sight definition and adequate target resolution. We had to grind a couple of lenses before we got it but I am very happy with the results.

For pistol I have a "jeweler's spot" ground to put focus on the front sight and located so as to be right for a Weaver stance. Have used this system for almost fifteen years on glasses I wear daily. FWIW I needed bifocals back in the late 80s--just took these routes and have not had any problems seeing what I needed to once I got the details sorted out.



The trick is to find an optometrist who will listen and work with you.
 
Status
Not open for further replies.
Back
Top