TargetTalk

I have been struggling with this for some time now to see my sights like I did years ago.

In the last 3 years I have gone to not needing any glasses to read, use the computer, and see my front sight clear to the point that I am using glasses for all close up activities. Long distance is still spot on.

What I have noticed is when using +1.75 to see the front sight sharp the target is so blurry my groups got larger which has has just moved my problem from the front sight to the target. What I have had to do is use an iris so that I can get the target and front sight in focus. I really did not want the target in focus as much as it is. The side effect I do not like is now everything thing is darker in the center and also the iris has made the front sight slightly fuzzy.

One solution I have started to use was to adjust my lens slightly higher than centered with my eye so that my front sight is now in the lower third of the area I can see through the iris where it seems to be brighter and more in focus.

I am sure others have ran into this and may have other solutions I can try.

Your reading glasses are not your shooting glasses. Your correction should be (your distance correction)+0.75. If you don't need distance correction 0+0.75=+0.75
Assuming you don't have astigmatism.

My bifocal correction is +2.0. I've experimented with +0.5 and +1.0, and I may yet try 1.5, but I found that +2.0 worked better than the lower corrections. At 2.0 the sights were sharp and the bull fuzzed out, but that turned out to be an advantage. I found that holding at the bottom of a fuzzy bull was easier and worked better than trying to keep a constant white space between sights and target. YMMV.

Lenny wrote:Your reading glasses are not your shooting glasses. Your correction should be (your distance correction)+0.75. If you don't need distance correction 0+0.75=+0.75
Assuming you don't have astigmatism.

Here is what I use:

Reading +2.25
Computer +2.00
Pardini/45 with irons +1.75
Free/Air +1.50
Pardini/45 with dot +0.50 (this is also my distance correction)

Before and after getting my eyes checked I have tried lots of different corrections and iris sizes but still have not been able to find an ideal setup. I was looking for inputs from others to see if anyone has had more success trying something different. I read all of Dr Wongs articles.

Chris, You are on the right track. Your different diopters relate to the different focal lengths of each task. Starting with your reading prescription is the strongest because the focal length is the shortest, approx. 16 inches. Moving out, the diopters decrease as the focal length to the various front sights increases. My free pistol front sight has 35 inch focal length. The red dot optic has a focal length of infinity, thus the same diopter as your distance prescription. My optical setup is very similar to yours but less powerful across the board.
Gort

I run a business helping shooters to see better for shooting. As far as I can tell, I'm just about the only one in the world who has approached this from an engineering/photographer's perspective. Shooting is different from most human vision, because you are trying to focus on two different objects at the same time, the nearby sight, and the distant target. Here is the math:

Diopters are inverse focal length, in meters. 2.00 diopter reading glasses focus at 1/2 meter, 3 diopter focus at 1/3 meter, 1.75 diopters focus at 1/1.75 = 0.57 m (1.75 is 7/4, so you focus at 4/7 if you prefer to use fractional math), etc. This is why someone posted that they use different reading glasses for different distances - they got it spot on. The higher the power, the closer it focuses you. Books are typically at about arm's length of 20" away, which is 1/2 meter, so reading glasses are often 2.00 diopters.

Diopters add. If you need distance correction glasses (which correct you to infinity), take that power and add +2 to have your corrected focus at 1/2 meter. This is why people's bifocals are typically "ADD +2.00" on their prescription. Also, if you take a pair of 2.00 reading glasses, and wear them on top of a pair of 3.00 reading glasses, you might look stupid, but you will effectively have a pair of +5.00 lenses. Now you can see REALLY close up.

To see infinity, you need zero diopters (1/infinity = 0)
To see your rear sight on a pistol that is 24" from your eye, you convert 24" to meters (0.61 meters), then invert that number (1/0.61 = 1.64).

So you need zero diopters to see the target, you need 1.64 diopters to see your sights. To get your focus so it falls between the two (so that neither goes too blurry), you just average the two. The average between 0 and 1.64 is 0.82. So a 0.82 diopter is your ideal lens for shooting a pistol with the rear sight 24" from your eye. You can re-apply the math for whatever you actually shoot, but there are two things to observe:

1. For pistols, base the math off the rear sight.
2. Lenses are available is 1/4 diopter steps. Always round down. So 0.82 diopters would round down to 0.75 diopters. And this is why one of the answers above was to use a +0.75 lens. He was exactly right, all I've done here is to add the math supporting it.

Art

In 2006 when my eyes required correction for both distance and close up (I could not see the front sight) I chose Lasik. I discussed the desired outcome with the eye doctor and the nurse, to obtain optimal correction. We agreed that both eyes were to be lasered incrementally, two times each actually, about a year apart. Now, I have optimal 20/20 vision in both eyes. A .50 lens in my shooting glass frames places the plane of focus exactly on the front sight (right eye dominant.). This surgery is not for the faint of heart. (My wife watched the first procedure and said, "Hell no!".) Having it done twice, can add to the anxiety, but produces fantastic results. My suggestion is to remember that your eyes are organic, and that they will change, whether due to age, atrophy, injury, or surgery.

Art said:

So you need zero diopters to see the target, you need 1.64 diopters to see your sights. To get your focus so it falls between the two (so that neither goes too blurry), you just average the two. The average between 0 and 1.64 is 0.82. So a 0.82 diopter is your ideal lens for shooting a pistol with the rear sight 24" from your eye

I could not disagree more, for pistol shooters, the focus must to or just behind the front sight and the target will be very blurry. A focal point between the front sight and target will leave the sight alignment out of focus, which is very detrimental for pistol shooters.
Gort

Two words: adjustable iris.

The iris (variable aperture) can help increase the depth of field (range of distances where focus is OK), but at the expense of reducing the light getting to the eye. If you shoot indoors, cranking down on an iris without a corrective lens is a good way to stain your eyes over a long match.

Take a look at all the high-end shooting glasses. The full-blown configuration is typically a combination of:

An adjustable iris

A corrective lens

Filters for different light conditions

I shoot indoors with an iris and a lens, and outdoors I add a filter. This gives me the maximum flexibility to get my sights & target just right.

Art,

In my opinion when shooting iron sights it is vital to have crisp and clear focus on the front sight. It should be the sole focus. You see the rear sight and target. The better my ability to focus on the front sight the higher my scores. I have noticed that it is harder to focus as long as I have in the past.

Playing with my adjustable iris seems to be working but still not ideal. I suppose this is the new normal.

I'm very fortunate; my optometrist lets me bring my pistol, and we go out to the parking lot and hang a target on the side of the building and she changes lenses in the trial frames until I'm satisfied.

+0.75 diopters over my distance prescription usually works well.

I had the works at my eye doctor yesterday. My eyes are great; it's the rest of me turning to shit!

Gort wrote:Art said:

So you need zero diopters to see the target, you need 1.64 diopters to see your sights. To get your focus so it falls between the two (so that neither goes too blurry), you just average the two. The average between 0 and 1.64 is 0.82. So a 0.82 diopter is your ideal lens for shooting a pistol with the rear sight 24" from your eye

I could not disagree more, for pistol shooters, the focus must to or just behind the front sight and the target will be very blurry. A focal point between the front sight and target will leave the sight alignment out of focus, which is very detrimental for pistol shooters.
Gort

One handed shooting (ISSF style) needs different lens than two handed shooting because of the distance to the foresight.
For ISSF pistol the ideal focal length is about 1 metre in front of the foresight.
When your eye is relaxed your focus is to infinity. When you put a object in front of the eye it will retract the focus to that object.
With focus just infront of the foresight the time to focus on the foresight is minimal and you can acquire the sights in the least amount
of time (needed for Rapidfire, Duelling etc.)
It is also easier to stay focused on the forsight with the least amount of eye fatigue.
You need to experiment with a defocus of +0.5 to +1.0 over and above your distance script.
Visit your optomitrist and take a copy of Dr Wongs articles with you.

I also use the combination of an Iris with a lens that allows for a clear sight of the front sight;A correction lower than the reading glasses will accomplish that;The more difficult task is to aim at a rather fuzzy 50 m/ yd distance target for obvious reasons

I have a set of lenses from +0.50 to +1.50 with the ability to stack them. I leave a +0.50 in my glasses that is fixed and swap out other lenses in a lens holder attached. This way I can play with a range of adjustments and then also adjust my iris. I still have work to do to find the correct setting but I am getting closer. Eye fatigue is a factor for sure that does not exist for me when I shoot with a dot as much.

Chris wrote:I have a set of lenses from +0.50 to +1.50 with the ability to stack them. I leave a +0.50 in my glasses that is fixed and swap out other lenses in a lens holder attached. This way I can play with a range of adjustments and then also adjust my iris. I still have work to do to find the correct setting but I am getting closer. Eye fatigue is a factor for sure that does not exist for me when I shoot with a dot as much.

That there IS fatigue is telling you something is wrong. The lens should have the eye in a relaxed condition while looking at the front sight. There may also be other problems with your vision that mere diopter adjustment will not help. To handle this myself, I had the +.50 added to my distance prescription in one lens which also took care of my astigmatism. I also use an iris, but not to "fix" focus issues.