Blur in the eye

[tsokasn]

Hello everyone!
I recently started shooting prone,and I must say that I like it a lot!!!
But something strange is happening for the last three days.
After about 30 shots,my right eye(aiming one)starts to blur?(it cannot focus right,can't see the bull as good as in the first shots).I asked a friend shooter about that and he told me that it's because og the bright sun.(you see here in Greece,we still enjoy the sun)He advised me to close the rear iris a little bit and the eye will be ok.I had the iris set at 1.1mm.
Is this right?Is it because of the brightness?How much must I close the iris?
Thank you!

[squiggly007]

What I usually do is try to get it on the bull, then I close it all the way and slowly start to open it until it comes into focus.

[xcrunner8k]

i use an anti-glare tube for the bright sun because my iris is narrow anyway (1.2ish) and in the sun it would need to be about 0.8. as for your eye problem, i experience the same thing if i strain my eye too much. and it happens very quickly, after about 10 shots. it's similar to trying to read a book in poor light; your eyes feel like they want to pop out. try to minimize staring at the target for too long.

[WarWagon]

I had a similar problem, and it ended up being eye fatigue. I was overcompensating because it turned out I had a slight astigmatism in my eye, even though I had better than 20/20 vision. A set of Champions took care of it.

[Albert B]

Perhaps a gray filter might help. Here in the Netherlands, when we shoot on an outdoor 50m range, the shooting point is covered but the targets are in the (bright) sunlight. As the shooter and his eyes are in a relative dark area the iris in the eye opens more then nessecery (relative to the amount of light from the target) and the light from the target starts to stray and reflect in the eye. An white glare or haze, covering the image is the result - making the eye very tired in a short time. Using a gray filter takes away part of the over-lighting.

We often train in the evening, when the shooting point and target are lit, but the distance between shooting point and target is completely dark. Then, much of the same symptons occur. We have found that the glare can be partly reduced by opening the front aperture a bit (0.2) and moving the rearsight forward. That way more light from the shooting point can pass the sight and enter the eye, making the iris in the eye smaller so less stray light enters the eye.

good shooting,
Albert B
(The Netherlands)

[Spencer]

Hello everyone!
I recently started shooting prone,and I must say that I like it a lot!!!
But something strange is happening for the last three days.
After about 30 shots,my right eye(aiming one)starts to blur?(it cannot focus right,can't see the bull as good as in the first shots).I asked a friend shooter about that and he told me that it's because og the bright sun.(you see here in Greece,we still enjoy the sun)He advised me to close the rear iris a little bit and the eye will be ok.I had the iris set at 1.1mm.
Is this right?Is it because of the brightness?How much must I close the iris?
Thank you!

Had an optometrist checkthe eye/s and the required lens?

spencer

[tsokasn]

First of all,thank you all for your answers.
Spencer,I am using shooting glasses with 4,5 deg of(what is the name of "I cannot see far"?)If I also have astigmatism,what can I do?
Albert B,I was thinking about filters.Interesting tip aboyt the fore iris.
WarWagon,the same with Spencer.
xcrunner8k,filter and anti glare tube will be my next purchase.
squiggly007,I will try your method.
Thank you again!

[peepsight]

Myopia is the general term for short sighted. So you are thus myopic.
Myopia is used more for severe forms of short sightedness but is still the general term for that condition.

My optometrist told me that no matter how young or healthy you are the first muscles in the human body to start complaining are the eye's focusing muscles which is usually caused by lack of oxygen in the blood.
Breathing exercises before each shot is a good way to increase oxygen levels in the blood and to the eye's muscles.

The same Opt. also told me that to rest the eyes now and again was a good remedy for these problems and you can only do that by looking away from your sights into the distance at infinity, this reduces the eye's focusing muscles back into neutral where they are 'resting', this then gives the muscles time to recoup.

Peepsight

[Shooting Kiwi]

As a teenager, I thought I had perfect vision, but experienced the same problems as you. I assumed this was normal. Wrong! Circumstances changed and I stopped shooting. By my late 20s I was wearing spectacles to correct minimal myopia and a little astigmatism. Now, in my 50s, with carefully corrected vision, I have little problem. I suspect that your shooting lens is not right.

How did you get your shooting correction lens chosen? It's not easy! You need to make sure your vision is corrected perfectly for focussing on the front sight, ideally with the eye relaxed, as if it were focussing at infinity. If you have a lens which is the same as your distance spectacles, it will not be correct for shooting.

Adjust the rear iris down, until the target dims, then open it out a bit. Don't use it to try to reduce glare - use coloured, grey or polariser filters for that. See what's best by experiment. You can get a rough idea by experimenting with lenses taken from sunglasses, temporarily taped to your shooting lens.

Don't hold your breath too long - your eyes need all the oxygen they can get.

Don't hold aim for too long, staring at the front sight. Close your eyes from time to time and/or look away from the sight for a little while. A static image on the retina will fade within a very short time.

All these effects get worse with age, but will get really obvious after age 40-ish for most people.

You say you have recently started shooting. You have been told to focus on the front sight, NOT the target, haven't you??? Do not expect the target image to be clear - it's the image of the front sight that is all-important.

Your aiming eye will tire more quickly if you are closing the other eye, so keep it open, and use a translucent 'blinder', so the non-aiming eye receives a lot of light. This will keep the aiming eye's pupil contracted and reduce the eye's in-built aberrations.

Go back to your optometrist, or, better, find one who understands the requirements of shooters, and have a long session getting perfect correction.

[tsokasn]

I feel so happy when you answer on my problem!
Peepsight,I will follow yoyr advice.
Shooting Kiwi,I focus on the fore sight.I had the opportunity to have sample myopic lenses from 3.75-4.00-4.25-4.50-4.75 degrees.I choose the one that focused best on the foresight!My spectacles have different degrees!
I wear shooting glasses with blinder.I will start breathing exercises between every shot,and now I am searching about colour filters.
You are great teachers!Thank you a lot!

[tsokasn]

What would be best?
Polarisers or colour filters?Or both?

[methosb]

You use polarizers to cut down glare and colour filters to increase contrast in different lighting (eg. yellow filter on dull days). So both is best (in an iris attached to the sight that is).

[guidolastra]

I have the same problem, the image becomes fuzzy. Interestingly, this only happens in prone or kneeling, so I do not know if the lens can also be to blame. I wonder if anyone knows about people/opticians/etc... dedicated to shooting glasses. Not the frames, but the lens...

[Shooting Kiwi]

Good point.

The lens in the shooting spectacle frame must be carefully aligned and positioned so that you are looking down the optical axis of the lens. Centring devices are available from the frame manufacturers to achieve this. It's a real fiddle to get it right.

For three-position shooting, it's not uncommon for shooters to have more than one set of frames, to accommodate the different head position, angulation, eye relief, etc.

[tsokasn]

The problem continues...
I tryied closing the rear iris,breathing,eye relaxing but nothing.Today was a very bright day and after about 30 rounds,blur on the bull.I don't know if this can be occured by the press on my chic by the chicpiece?(I think that I will buy a polar len for the foresight)

[Shooting Kiwi]

You say "blur on the bull", but you should be focussing on the front sight - the bull will be blurred, even if you have perfect vision. Do you mean that the front sight image stays unchanged and in focus, whilst the bull gets so blurred that you can hardly tell where it is? Or are things so bad that you can't see the front sight properly, either?

I still think you may have chosen the wrong lens - it really can be very difficult to get it right. You can often compensate for the wrong degree of correction, but your eye will fatigue after a time, and when that happens, you will experience a fairly sudden and severe deterioration of vision. It may take 10 minutes or more to recover. It's nothing to do with pressure on your cheek. Have you tried a contact lens? If you have severe astigmatism, a contact lens won't correct your vision, but some people find that contact lenses can produce better correction.

[tsokasn]

Shooting Kiwi
You described it perfectly!
The front sight image stays unchanged and in focus, whilst the bull gets so blurred that I can hardly tell where it is.
What do you think is the cause of the problem?

[Shooting Kiwi]

This has to be either the depth of focus of your eye is reducing as you shoot, or it is becoming effectively more short-sighted (myopic) as you shoot, or both.

The smaller your pupil, the greater the depth of focus your eye has. Perhaps your pupil size increases as you shoot. Perhaps this reflects changing stress or light levels.

I cannot undestand why your eye should become more short-sighted. The relaxed state of the eye is when it is focussed at distance, therefore I would expect fatigue to tend to make the eye more long-sighted, or, more correctly, less able to focus at close distances.

How old are you? If you are 40+, you probably are beginning to notice that you can't change focus from near to far objects (and vice-versa) as quickly as you could when you were younger. If you are, say, reading for a long time, and then look up, to see something in the distance, you may find that it takes several minutes before you can focus on the distant object. This is because the lens of the eye becomes less elastic with age. Eventually, you lose almost all focussing ability, need bifocals or varifocals, or spend most of the day looking for one of your several pairs of spectacles!

If this is the case, are you (unconsciously?) constantly shifting focus between front sight and target? You must not do this! You must focus on the front sight only, and accept that the bull is blurred. The amount to which the bull is blurred then depends on the depth of focus of your eye, perhaps modified by the pin-hole rear sight aperture. Some people suggest making the rear aperture very small, thus increasing depth of focus, but this makes the sight picture too dark, and brings in other problems, such as diffraction effects. The standard adjustment of the rear sight aperture is to close it until the sight picture becomes a bit dark, then open it until the sight picture is of 'normal' brightnes.

So I still think that you have the wrong lens for shooting. You need to select one that allows you to shoot with your eye relaxed, as if gazing into the distance. Correction then needs to be applied, to put the front sight into focus, at the near end of the eye's depth of focus. The difficulty is that your pupil size will be different when you shoot and at the optometrist, and, as I said, small pupil = bigger depth of focus.

One way around this might be to try disposable contact lenses. Optometrists usually can be persuaded to give a selection (free!) to try. You might find that the addition of a weak 'negative' contact lens, used in addition to your shooting spectacles, pushes your relaxed point of focus further away, and helps. Experiment to get guidance on what lens you need for your shooting frames.

There is no substitute for using an optometrist who shoots. Mine does, but, even then, it has taken several visits to get my correction (almost) right, and I'm now thinking that I really need several different lenses to help with different conditions and because my eyes seem to change from day to day. Sometimes it's a nuicance getting old, but it's better than the alternative!

Hope this helps.

[Hemmers]

After about 30 shots,my right eye(aiming one)starts to blur?(it cannot focus right,can't see the bull as good as in the first shots).

The technical answers all have merit. But a simple question - what is your shooting cycle like?
If you're staring down the sights all the time, you will quickly get retinal burn which will degrade your sight picture. I ensure that I look away between every shot (without moving my head), and actively force my right eye to focus on something else - the little manufacturer's marks on the ammo casings, the batch number on the end of the box. Anything that isn't black and circular!
I also tend to take 2 scheduled breaks in an ISSF match - one every twenty shots or so (obviously move them around if I'm struggling, etc). This also gives me an opportunity to get up and focus on something else.

Check it's not just retinal burn before you go and spend loads on equipment!

[Shooting Kiwi]

.... but the front sight is said to remain crisp, so I think retinal fatigue is unlikely.