[shooter86314]

I am struggling with my astigmatism and my scoped rifles. Several eye exam during the past two years have yielded various prescriptions for my shooting eye, none of which work real well, depending on the day.
Would it be possible to buy a set of round lenses (40 mm) with various astig corrections only (in 1/8 power increments), utilizing the adjustable eyepiece to focus the reticle and target?

 

[Patchhound]

To the best of my knowledge(and my knowledge is pretty minimal on most subjectsRNGR2), astigmatism is corrected by changing the axis(rotate) and not the power. PM Shootingsight and see what he has to say, or he may pop on here.

What are your symptoms?

Astigmatism usually plagues shooters when they move from one position to the next because your head position on the stock will change.

 

[bloodhound13]

Read post #7

http://m14forum.com/vision/147051-astigmatism-shooting.html

 

[Eyeguy]

I am struggling with my astigmatism and my scoped rifles. Several eye exam during the past two years have yielded various prescriptions for my shooting eye, none of which work real well, depending on the day.
Would it be possible to buy a set of round lenses (40 mm) with various astig corrections only (in 1/8 power increments), utilizing the adjustable eyepiece to focus the reticle and target?

Curious, are you getting good vision from your current glasses for other day to day activities; driving, reading, etc? If not, that's an issue that needs to be nailed down first. The "art" of refraction (determining the amount of power needed to correct vision) is just that, an art, and some doctors are simply better at refraction than others. I always suggest an independent optometric physician as offering the best opportunity for a good refraction.

You also mention that none of the prescriptions you've had "work real well, depending on the day". Is the variable environmental, i.e. lighting conditions, distance or other? Visual changes that occur daily could indicate some underlying pathology but your doctor should have detected any issues during the exam.

In his reply, Patchhound mentions that a component of astigmatic correction is the rotation or axis of the prescription lens and he is correct. Another component is the amount of power used to correct your particular astigmatic error. Again, a good refraction should be able to resolve this correctly if the eye is otherwise healthy.

Other variables do exist; age, the type and quality of lens used to correct your vision. Can't fix aging but you can "buy up" in the lens category to digitally manufactured lenses (think CNC) that are more accurate in manufacture and if properly fitted compensate for some of the optical error that occurs in simple designs as the eye moves away from the optical center of the lens. Those needing stronger corrections typically benefit the most using this type of lens. Your doctor should be able to tell you if digital lenses would offer a tangible benefit given your objectives. You may also want to consider adding an anti-reflective (AR) coating to your prescription lenses if you've not already done so. AR coatings not only reduce reflections on the surface of the prescription lens, they also allow the lens to transmit more light into the eye; as much as 10-12% more light depending on the material used in your prescription lens. AR lenses will require a little more care on your part but are likely worth the investment as they will allow you to see better in marginal lighting.

In the link posted by Bloodhound, member ShootingSight talks about using a modified prescription lens or clip on lens to bring the front sight into better focus and balancing your depth of field between front sight and target. He's spot on with his info and perhaps this approach would help you IF your problem is bringing the front sight into focus but you mention scoped rifles specifically so don't think a compensated prescription is called for here.

I wear strong prescription glasses; very near-sighted with 2.5 to 3.0 diopters of astigmatism in each eye. I have no issues with using a scope as long as I've; a. adjusted the eyepiece correctly and b. set the parallax/distance correctly for the target.

Good Luck and PM me if I can answer any questions for you.

 

[JEFFJP_N_JJ]

I just spent $500 on a new prescription and new glasses that do not work!
I even went to an Optimalist (sp) Dr of...

Took the glasses back and had them 'refined'?

I still see double and my targets are blurry and have my scope set at 300 when I am at 100!?

Where does one find a 'real' eye doctor?

 

[Eyeguy]

I just spent $500 on a new prescription and new glasses that do not work!
I even went to an Optimalist (sp) Dr of...

Took the glasses back and had them 'refined'?

I still see double and my targets are blurry and have my scope set at 300 when I am at 100!?

Where does one find a 'real' eye doctor?

Not sure how to answer that question Jeff. Typically, an independent doctor, one who owns his own practice, is more fully vested in the process and in meeting patient expectations. This isn't to say that optometrists working in commercial environments are not competent but those doc's typically don't have a vested interest in the "optical" side of their business.

California is one of the states that require opticians to be licensed offering some assurance that the person, fitting your glasses, will have had training and should exhibit a working knowledge of managing optical error (interesting that fewer than half of the states in the US require opticians to be licensed). Don't be afraid to ask your optician if they're licensed.

One suggestion, at the time of the exam, ask what your best visual acuity is; you'll hear something like 20/20 or 20/30 vision. 20/20 acuity is considered "normal" good vision but not everyone is correctable to that level. Once you have that information and glasses are made, ask to have your visual acuity checked wearing your new glasses.

I always advise being transparent with your medical professional. If you're not satisfied, let them know. A good doc will want you to be a happy, repeat customer in their business.

 

[JEFFJP_N_JJ]

Not sure how to answer that question Jeff. Typically, an independent doctor, one who owns his own practice, is more fully vested in the process and in meeting patient expectations. This isn't to say that optometrists working in commercial environments are not competent but those doc's typically don't have a vested interest in the "optical" side of their business.

California is one of the states that require opticians to be licensed offering some assurance that the person, fitting your glasses, will have had training and should exhibit a working knowledge of managing optical error (interesting that fewer than half of the states in the US require opticians to be licensed). Don't be afraid to ask your optician if they're licensed.

One suggestion, at the time of the exam, ask what your best visual acuity is; you'll hear something like 20/20 or 20/30 vision. 20/20 acuity is considered "normal" good vision but not everyone is correctable to that level. Once you have that information and glasses are made, ask to have your visual acuity checked wearing your new glasses.

I always advise being transparent with your medical professional. If you're not satisfied, let them know. A good doc will want you to be a happy, repeat customer in their business.

I went this time to an DR of Optimogiy and told him I was a rifle shooter...

Had a good one some years ago but no idea where he is now...:-(

I have prizum issues!

 

[Eyeguy]

I went this time to an DR of Optimogiy and told him I was a rifle shooter...

Had a good one some years ago but no idea where he is now...:-(

I have prizum issues!

Hmmmm... The prism brings in a new challenge. Prism in a lens is typically used to correct double vision caused by an imbalance in ocular muscles. There can be other causes but the muscle imbalance is the most common cause.

There is a sub-speciality in eyecare care called an Orthoptist. They are NOT optometrists or ophthalmologists but are specifically trained to work with binocular vision (see this link for a further explanation of their scope of services: http://www.eyecareprofessions.com/orthoptist/). The Orthoptist will work in conjunction with either an Optometrist or Ophthalmologist.

Prism correction for double vision can be tricky. I had a patient some years ago who exhibited the need for differing amounts of prism depending on when he was gazing; up, down, right or left. Hopefully, your's is not so complex and can be properly corrected by a trained professional. Remember, you can only experience double vision when using both eyes. For a shooter closing one eye, this shouldn't present a problem.

 

[JEFFJP_N_JJ]

Thank you Eyeguy!

 

[JEFFJP_N_JJ]

My friends all laughed at me this past November at deer camp when I commented about all the planes flying over in formation...lol

I DO see double!

Makes it hard to shoot good groups!

 

[Dougboffl]

As a kid I was diagnosed with Astigmatism. Worn B&L Toric lenses most of my life. At age 40, I went to Paragon CRT/GVSS lenses I wear only at night when sleeping. Supposedly, the CRT either corrected the Astig or I had been mis-diagnosed. Not sure how that worked but happy now at 54 still wearing the CRT nightly. In the last few years I have added a pair of distance glasses for going to movies and things at night. No reading glasses needed.

 

[Eyeguy]

As a kid I was diagnosed with Astigmatism. Worn B&L Toric lenses most of my life. At age 40, I went to Paragon CRT/GVSS lenses I wear only at night when sleeping. Supposedly, the CRT either corrected the Astig or I had been mis-diagnosed. Not sure how that worked but happy now at 54 still wearing the CRT nightly. In the last few years I have added a pair of distance glasses for going to movies and things at night. No reading glasses needed.

Good share Doug. CRT contact lens (corneal refractive therapy) work by fitting a contact lens to the cornea that is flatter than the cornea itself, and gently reshaping it over time. CRT is a proprietary product by Paragon.

In general, the process is called orthokeratology. Typically, orthokeratology is used for people who are near-sighted, astigmatic or who suffer from a combination of both. Orthokeratology is only effective if the asymmetry of the eye (if you suffer from astigmatism, something in the eye is out of round; think football vs basketball) is in the cornea. Astigmatism can also be the result of the inner crystalline lens being asymmetric; that's called lenticular astigmatism. It's less common but a malady for which orthokeratology is ineffective.

Another refractive option is "clear lens extraction". This is the same process that is used when cataracts are present but in this case, are used to extract a healthy crystalline lens and replace it with a synthetic lens. Technology today has reached a point where pre-surgical testing can be done to closely determine the power needed for the synthetic lens, often leaving the post-surgical patient with good vision and without the need for further correction.

 

[Dougboffl]

Eyeguy,

My Optometrist mentioned if I ever develop cataracts a lens replacement would basically fix everything. I got excited thinking about doing it as an elective procedure till he told me it can run about $7k, per eye.

 

[shooter86314]

I appreciate the assistance. My eyes are in no man's land. The Docs cant gete my right eye to 20-20, and my cataracts aren't bad enough to rate replacement by the VA.

I though if I used the lens to correct only astig, I could adjust the focus with the eyepiece.

 

[ShootingSight]

There are several factors at play here.

Astigmatism correction is, as has been mentioned above, both a combination of the power of the cylinder, and the axis. In theory, once you get an astigmatic correction in your lens, you should be set. However, there are some exceptions to think about:

1. Astigmatism is a bulge in the conea. Sometimes this bulge can change, based on the pressure you exert on the soft tissue surrounding the eye. So when you form a cheek weld, your astigmatism could change from what the doctor measured, and indeed might even change between positions. I expect this is not common, but I know at least one shooter who has this issue.

2. Lenses work properly when you look through the center of the lens, and more importantly, when you look perpendicular through the lens. When you start to look diagonally through a lens, you create an astigmatic error. So in shooting with regular street glasses, especially in prone position, you aim while looking through the extreme upper inside corner of your lens, and you are looking at almost a 45 degree angle through the lens. The amount of error you get here depends on how strong your lens is to start with, so not everyone has this issue, but it could be a factor.

All scopes have adjustable eye pieces that allow you to adjust sphere power, I have yet to see a scope that adjusts cylinder power. But to answer your original question: yes, I have made cylinder corrected lenses for people that they glue into a lens cap for their scope, so they add cylinder correction to their scope. That would do several things for you. First is it would present the lens perpendicular to your line of sight, regardless of shooting position, it would also allow you to swap between powers, and finally, it would let you manually tune your axis, as you can rotate the lens cap. This last thing is a 2-edged sword, as eyepieces usually rotate to tune sphere, which will rotate your axis, so getting the focus set up is a little tricky to twist the eyepiece while holding the lens cap stationary. Good news is that if you paint a line on the lens cap skirt, you will know where it goes and can get it back tot he same spot.

I don't recommend trying to go with 1/8 step lenses, both because they are difficult to source, but also I do not think they are necessary. If you want to play, I'd suggest your prescribed cylinder, and then get two more of +0.25 and -0.25 shperes - though even there - I'd start with the right one first. It could be that just mounting it on the scope solves your problem.

I make lenses for $40 that are AR coated. If you order, I need to know the scope diameter, and I can cut the lens. I can't help with the lens cap, it would be up to you to see how it is mounted.

Two more quick things. First: Hydration level and blood sugar level (actually glucose level inthe ocular fluid) will drive the focal length of your eyes, so stay hydrated, and eat through the day if you are shooting a match.

Also, focus your scope by screwing the ocular all the way out to start, then screw it in while looking through it, and stop as soon as it comes into focus. THis is the point that your eye is doing the least work. I used to screw it to find max/min positions, and try and go half way between. THis is wrong. You want the eyepiece screwed as far out as possible when shooting.

Art

 

[Eyeguy]

Eyeguy,

My Optometrist mentioned if I ever develop cataracts a lens replacement would basically fix everything. I got excited thinking about doing it as an elective procedure till he told me it can run about $7k, per eye.

Yep. Unfortunately, I'm not aware of any insurer that covers any part of an elective procedure.

 

[shooter86314]

JEFFJP said:

I still see double and my targets are blurry and have my scope set at 300 when I am at 100!?

LOL. I could have written that! In the past two years, I have been to optometrist F several times for a shooting lens, I have been to optometrist G (a small bore shooter, who spent two hours on me), to an ophthamologist at the VA (bless her heart, she spent an hour on my exam), and to another ophthamologist R and a retinal specialist.

My experience is that a different lens will work best on any given day. Also, head/eye position is very critical.

PS. my spellcheck doesn't like the way I spell that optimalist, either.

 

[JEFFJP_N_JJ]

I hear you shooter86314!

But it is still fun to send 'em down range where ever they may be...

 

[hnthomps]

Eyeguy,

My Optometrist mentioned if I ever develop cataracts a lens replacement would basically fix everything. I got excited thinking about doing it as an elective procedure till he told me it can run about $7k, per eye.

Based on my recent experience, torric lenses that correct for astigmatism cost about $1500 per eye more than standard lenses. If you elect to use a laser type of surgery instead of the manual type, it is also an extra $1500 per eye but I believe that the results are better. Those prices are out of pocket and in addition to the initial surgery cost that should be covered by insurance if your eyes are such that the work is medically required.

Nelson

 

[hnthomps]

I just had my last post surgical follow up check at 28 days after my last eye surgery. The last one done may not be fully stable, but I will head back in three weeks for a final prescription for my reading glasses. I was seeing 20/20 today with both eyes and can still read a normal sized book print without glasses if the light is decent. The optometrist said that he would have thought that I had my original lenses if he had not known better after seeing a surgical report. The laser assisted surgery was extremely precise with excellent healing and I am happy that I paid the extra for this method.

I plan to start shooting a few rounds this weekend if the weather cooperates and see how much my zero has changed with the new lenses installed.

Nelson