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Iron Sights vs Old Eyes

Posted: Fri Dec 06, 2013 1:45 pm
by heli_av8tor
I'm returning to shooting after several decades of inactivity and finding that the eyes ain't what they used to be. Focusing on the front sight with progressive bifocals requires the head tipped back to an uncomfortable angle. I tried single focus glasses that brought the front sight into better focus but it just didn't seem to work well for me.

How are others combating this problem?

Anyone had laser corrective surgery with the dominant eye set for close and the other for distance?

Am I doomed to Red Dots?

Posted: Fri Dec 06, 2013 3:35 pm
by DLS
I've had a number of eye surgeries (not Lasix) that has resulted in 'mono-vision' where my dominant eye is set for near and my other eye set to infinity.

I have retinal wrinkling so my entire vision is wavy (think of looking through crinkled cellophane) but I find I can still shoot iron sights at 54 years of age. If the retinas were smooth I think I would have an awesome sight picture.

The biggest drawback I have is that my non-dominant eye sees the target very clearly since it's permanently set at infinity by an artificial lens. This makes it impossible to shoot with both eyes open without a blinder, otherwise I have two very clear (relative to my vision) images at two different focal lengths and I have not found a way to train my brain to ignore one over the other.

So I tape the top 2/3'rds of my shooting glasses. This allows me to use the spotting scope by peering under the tape

As my eyes continue to age and my near point focus moves farther away a dedicated set of lenses will be in order (either prescription or shooting glasses), but for now I can still see the front sight of a pistol well enough to not embarrass myself, but it's not longer crisp.

I hope all of this somehow helps!

Posted: Fri Dec 06, 2013 4:24 pm
by brent375hh
Try poking a 1mm/.040" hole through a business card and holding that up to your eye and looking through it. If that is a help, a clip on iris might be beneficial.

Posted: Fri Dec 06, 2013 4:56 pm
by RandomShotz
Every surgery has some risk, even Lasix - I would avoid it especially since there is a very effective non-surgical alternative. I had cataract surgery before there were replacement lenses that provided some accommodation. In essence, my eyes have a fixed focus at infinity (actually, 20 ft and beyond). I have progressive lenses and ran into the same situation that you described. I still shoot with my regular glasses from time to time just to make sure I can still do it, but it requires an uncomfortable posture. I bought Knobloch shooting glasses from someone on this forum when I started shooting and it has made all the difference. The key is to get a lens that suits the distance from your eye to the front sight which varies with stance and gun length. Since you apparently have normal age-related presbyopia, you still have some accommodation and should have little problem getting a lens that will suit.

The clip-on iris has the effect of increasing the effective depth-of-field and may bring the front sight into focus, but has the corollary effect of cutting down the amount of light that you receive. That may work outdoors on a good day, but I shoot at an indoor range and the iris I tried just made things too dim. I didn't like the weight either, but could probably have learned to live with it.

Reading glasses will serve somewhat, but they have the drawback of no adjustability. You will have the clearest image if the optical center of the lens is directly in front of your pupil and the axis of the lens is aligned with the axis of the eye. That is why shooting glasses have all those funky adjustments.

Roger

Posted: Fri Dec 06, 2013 6:06 pm
by Heddok
At age 58 my eyes have gotten to the point the front sight is clear without glasses so I shoot with plain safety glasses.

When I was shooting Palma rifle at a match years ago. I was paired with an older gent in his 70's (I was 49). I asked him about aging and shooting and he said:

The arthritis locks my joints in place so the rifle doesn't wiggle around
The cataracts cut the glare from the sun on the target, and
The dementia helps me forget my bad shots.

He proceeded to whip everyone's butt
Helluva a nice guy and one who I still miss

Re: Iron Sights vs Old Eyes

Posted: Sat Dec 07, 2013 7:45 pm
by jliston48
heli_av8tor wrote:I tried single focus glasses that brought the front sight into better focus but it just didn't seem to work well for me.
I don't understand why this is and you haven't explained why it didn't work for you. Were the "front-sight focus" glasses designed by an optometrist or was it a do-it-yourself job? If it was a DIY, then see an optometrist for an assessment, test and proper lenses that correct problems (astigmatism, etc) and gives you the correct focus. If you have already done this (which I assume you have because you have bifocals), it could be the prescription.
heli_av8tor wrote:Anyone had laser corrective surgery with the dominant eye set for close and the other for distance?
This sounds a bit serious - not to mention CRAZY!

Re: Iron Sights vs Old Eyes

Posted: Sat Dec 07, 2013 9:39 pm
by DLS
heli_av8tor wrote:Anyone had laser corrective surgery with the dominant eye set for close and the other for distance?
This sounds a bit serious - not to mention CRAZY!
Actually it's not crazy at all. It's called mono-vision and it allows you to see without glasses or contacts. If you have good distance vision in both eyes you need glasses for up close viewing (readers).

If you have good near point vision in both eyes you need glasses to see at a distance.

If you set one eye to each your brain soon learns to choose whichever eye give the proper focus, then you can dispose of all glasses for most normal activities.

Some folks can't handle it, but most can. Your eye doc will set you up with contacts or temporary glasses that provide this effect if someone wants to give it a try before hand.

I'm near sighted (besides my retinal issues) and I have been using one contact in one eye for distance for years. I teach, and it allows be to see my notes on the lectern without having to put readers on and off. When I look out over the classroom I can see the student with clarity. It's so much better than having to put glasses on and off again.

I also coach baseball. If I'm playing catch with a player it's interesting as the ball will first be picked up by my distance eye and as it get close enough my other eye will take over to watch it into the mitt. It's seamless and the two focal lengths do not affect my depth perception.

Sorry for the long-winded post ... I hope it's helpful to someone.

Posted: Sat Dec 07, 2013 9:51 pm
by heli_av8tor
The single focus lens I tried was not from an optometrist. It was off-the-shelf readers that I use for reading music. (Changing head position as I go down a page to maintain focus doesn't work for me playing a wind instrument either.) Perhaps the optometrist could do better. Also, I may not have given it enough time for me to adjust.

DLS explained the common practice of adjusting eyes with Lasik to focus one near and one far.

I agree, if I were contemplating the surgery only for this shooting problem I would be nuts.

Thanks to all who responded.

Posted: Mon Dec 09, 2013 12:46 am
by ShootingSight
Solution is actually quite easy.

Lens strength in glasses actually determines where your relaxed eye focuses.

In our youth, out eyes had a relaxed focus at infinity, and we could exert the ciliary muscle in out eye to draw the focus near. As we get older, the lens get hard, and that adjustment capability is lost. However the optimal focal point we used to adjust our eyes to can be re-established if we only know where to focus, and what lens gets us there.

As it turns out, this is a common problem for photographers, and they have a solution. If you are trying to take a picture of a person, and also want the mountains behind them in focus, you need to do two things:

1. You want a big depth of field. This is accomplished by using a small aperture (ie smaller than your pupil), as was described by cutting a hole in a business card. THere are other commercial systems for getting small apertures, I give people small aluminum foil stickers that I drill.

2. You want to adjust your lens to focus BETWEEN the person and the mountains, so the person is inside the near edge of your depth of field, while the mountains are in the far edge of the depth of field. This in-between distance is called the hyperfocal distance, and you can google it if you want the gory math. But the bottom line answer is that you want a +0.75 lens added to your distance prescription for shooting pistol. If you don't need glasses for distance, just use a +0.75. This lens will bring your focus in far enough to get a clear front sight, without coming in so close that the target is too blurry. Off the shelf readers usually do not work, because the lowest power they come in is +1.25, which is much too strong. It will pull in your focus so close that you will see a FANTASTIC front sight, but it will be in so close that the target is gone.

Most eye doctors know this concept, but the need to focus between objects is outside the context of most human vision, so they will often not jump to this solution unless you prompt them that you want to focus at the hyperfocal distance of the front sight.

Also, do not use progressive lenses. Your apparent elevation in shooting is a finction of your focal point. Since progressives have varying focal points, any slight shift in head position, or glasses position on your head will cause you to string your shot groups vertically - it'll drive you batty.

In the interest of full transparency, I sell safety glasses with a +0.75 diopter built in, exactly because my eyes went, so I pulled out my old photography books and went through the theoretical lens math. And it works. Unfortunately, I'm out of stock for the moment, but if you are going to your eye doc for a solution, you can just tell him you want a +0.75 ADD ('add is the medical term for lens power above your distance correction), in a single power lens.

If you want to be really cheap, you can order glasses on-line, just take the first value in your prescrription and increase it by +0.75.

Art Neergaard
ShootingSight LLC
shootingsight@nuvox.net
www.shootingsight.com

Posted: Wed Dec 11, 2013 7:40 am
by seamaster
Order your lens +0.75 addition to your distance.

If you don't have Champion or Knobloch shooting frame, just move your shooting eye pupillary distance outward by 5mm to compensate the lateral gaze. El cheapo shooting glasses is just as good as Champion's.