Archery sight

[Lewy]

I have recently glazed an bow sight for an archer. His spectacle correction is +0.25/-1.00 x 80. On looking through a pinhole on the bow with the above correction placed at arms length away, the round target appears oval. I have since ammended the lens to +0.50/-050 x 80 but he is still geting the same problem. Any suggestions apart from trial and error of getting him a clear and accurate target, as getting his accuracy up just a notch should get him into the Engalnd squad.

Lewy

[ikon44]

I have recently glazed an bow sight for an archer. His spectacle correction is +0.25/-1.00 x 80. On looking through a pinhole on the bow with the above correction placed at arms length away, the round target appears oval. I have since ammended the lens to +0.50/-050 x 80 but he is still geting the same problem. Any suggestions apart from trial and error of getting him a clear and accurate target, as getting his accuracy up just a notch should get him into the Engalnd squad.

Lewy

a contact lens would ensure abberation free vision.

[Robert Martellaro]

Lewy,

It could be due to the cyl- you might want to lose it altogether. Are there any adjustments for lens tilt?

Regards,

[chip anderson]

If patient is looking through a pinhole, why does he also need Rx?

[MTP]

Are you using a flat form glass lens? If not this may help, it could reduce centre substance and therefore the spectacle magnification, also try to get it absolute minimum diameter for the sight.

[HarryChiling]

Great call chip, if a patient is looking through a pinhole he should be seing 20/20 unless there is some underlying condition where he does not have 20/20 vision. I would assume the hole wold have to be larger than this for him to be seeing a circle as an oval. If it is than keep in mind the vertx distance as well. The lens may be sitting too far from his eye. I don't know the distance of the sight but would have to assume that the lens is being mounted on the far side of the sight and would make a difference even in a Rx that low if the distance was great.

[MTP]

From memory most sights for rifles and I would assume archery a small diameter aperture, of maybe between 3 - 5 mm, rather than a pinhole. I think the idea is to try to eliminate visual clutter and distraction rather than create a pinhole effect and this is why the lens abberations come more in to play.

[Lewy]

From memory most sights for rifles and I would assume archery a small diameter aperture, of maybe between 3 - 5 mm, rather than a pinhole. I think the idea is to try to eliminate visual clutter and distraction rather than create a pinhole effect and this is why the lens abberations come more in to play.

You are right on this one, the aperture is about 3 to 4 mm diameter. So should you reduce the cyl power, remove it altogether...........? I shall be seeing this chap soon and don't want to mess about too much.

Lewy

[MTP]

Hi Lewy,

I wouldn't remove the cyl as this is what is giving him the optical correction, and I wouldn't go down the route of cl's as he would be primarily dependant on the cyl and therefore there could be stabilisation issues when he is lining up on target - especislly with reduced blinking/lens drying.

Is the lens mounted within the sight mechanism?
Does he normally wear the correction?
When he is using the bow is he in primary gaze?
These would all be worth knowing, it may also be worthwile to get him in with the bow and get him to line himself up as though he was on target just so that you can see exactly how he does it.

One solution may be for him to wear the correction, rather than have it incorporated in the sight, but he may not initially like this and you would need to watch the centration. Otherwise flat form glass lens incorporated in the sight (with AR?) is probably still your best bet. You will need to get the lab to mark 12 o'clock and 6 o'clock positions on the lens so that he can put the lens in and out himself.

[snowmonster]

Why not go outside with the guy and his bow (or at least have him look out a window) and use some trial lenses (not contact lenses) and see what works best based on your initial refraction? That would be the most real-world way to figure it out without having to re-make glasses all the time.

-Steve

[chip anderson]

Snow:

This would constitute an eye doctor who actually addresses the problem at hand. Scarey, indeed. Haven't known one to do this since the Death of Sam Johnnson, at U of Miss. Medical Center, he used to have patients with this type problem bring thier rifles up to his office on the third floor and refract there, with them sighting out the window.
Shoot, next you're going to want them to take time off from refractive surgery and treat eye infections.


Chip;

[HarryChiling]

he used to have patients with this type problem bring thier rifles up to his office on the third floor and refract there, with them sighting out the window.

I would not want to be on campus looking up at his window during this refraction. :D

[snowmonster]

I would not want to be on campus looking up at his window during this refraction. :D

While I have actually done this type of thing myself (and I was only about 27 at the time), that's exactly what I was thinking while reading that.

Good thing he wasn't working in downtown Dallas when he was doing this...

-Steve

[MTP]

This is something I quite often do with sports specific eyewear patients (seems to be quite often marksnmen for some reason), can be a bit scary the first time they assemble the gun in the consulting room. Most of them really appreciate someone taking the time to find out exactly what they do and as they are often quite fond of their sportrsgear are quite happy to show it off.

Now I just need to convince an airline pilot that I have to review his visual requirements in situ ...