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Fresnel Lenses, Cataract Surgery, and Sight Picture

Posted: Fri Jun 10, 2022 3:50 pm
by mhampel
I searched the sight for posts on cataract surgery and could not find anything very resent. In 2016 there was a recommendation to get multi focus lenses. I chose those. Not because of that post, but because I wanted to go forward with the best vision, glasses free that I could.

Good news – my sight picture is brilliant. It looks just like the ideal pictured in books. The ring is in focus, round and black. Likewise with the bull. In focus, round and black. I have been shooting with corrective lenses for many years and have never had such a remarkable sight picture.

Now the other news. The multi-vision cataract replacement lenses are miniaturized Fresnel type lenses. Wikipedia has a good description of what these are and how they work. Think in terms of a thin sheet of plastic. Here is a short quote from Wikipedia - “Such a lens can be regarded as an array of prisms arranged in a circular fashion, with steeper prisms on the edges, and a flat or slightly convex center.”

I am convinced that very small changes in head position. I'm talking fractions of a millimeter cause the target image to move to another section of the lense. Jumping to a different prism which causes the target image to be somewhere it isn't.

Please – someone convince me I've gone mad. I break what appear to be good shots and am often rewarded with wild, unexplained wide shots. And I'm not talking about small errors.

If I'm not insane, does anyone think something like the MEC Duplex Vario, or maybe trying to shoot with a MEC mirror would help. (Can you actually shoot with the mirror, or are they only for perfecting setup?)

Re: Fresnel Lenses, Cataract Surgery, and Sight Picture

Posted: Fri Jun 10, 2022 4:22 pm
by Frank in Fairfield
I don’t know about the MEC lenses but I had cataract surgery a couple of years ago.
My surgeon was just back from the desert where he treated combat wounded.
He asked what my hobbies were?
I said I shoot air rifles, hunt big game and shoot varmints at very long ranges.
I told him my friend in Kansas had the surgery but opted for near and far vision which requires him to where glasses for everything.
The doctor (Colonel) advised me to get FAR vision in both eyes.
He was absolutely correct.
Now, I use glasses only for reading and typing on the computer.
Shooting, open sights, aperture sights or with a scope I need no correction of any kind.
I can focus on the front sight and the target regardless of arm or distance.
As an Air Force retiree I want to thank the American Taxpayer (wait, that’s me) for my new eyes.
A bonus: I get to wear some great sunglasses that I could not wear when I needed bi-focals..

Re: Fresnel Lenses, Cataract Surgery, and Sight Picture

Posted: Fri Jun 10, 2022 6:55 pm
by Anschutz
mhampel: sorry you're having issues.

Frank in Fairfield: Thanks for your post. I've talked with a few F & Bench shooters at our range that had cataract surgery and did same as you. They've been very happy. I have cataracts, which are not advanced enough for surgery but does interfere with iron sights. Oh well.

Re: Fresnel Lenses, Cataract Surgery, and Sight Picture

Posted: Tue Jun 14, 2022 7:05 pm
by Martin H
mhampel,
What discipline are you shooting? I am assuming iron sights if you want to use a Duplex?

Before you splash out money on a Duplex I would try to diagnose your issue by eliminating any other reasons for your wild shots.
If you can get access to a Scatt I would use it to help with diagnosing the problem.
Live fire using Scatt will check if your shots are going in the same area as the Scatt suggests. If not, you could be having rifle/ammunition issues.
Dry fire using Scatt is a good way of checking your hold, sighting and triggering.

It seems strange that you having flyers when you are seeing the sight picture so well, there could be reasons other than your vision that are causing the flyers.
Cheers Martin

Re: Fresnel Lenses, Cataract Surgery, and Sight Picture

Posted: Tue Jun 14, 2022 9:57 pm
by Mike M.
I had cataract surgery a couple of years ago. When the doc found that I was a shooter, he recommended monofocal IOLs without hesitation. I went with that, plus LASIK for fine-tuning and correction of astigmatism. Distance vision is now 20/20 or better. Yes, I need reading glasses...but I used to wear glasses every waking moment. So it's not a particular burden.

Re: Fresnel Lenses, Cataract Surgery, and Sight Picture

Posted: Wed Jun 15, 2022 11:49 am
by mhampel
Martin - thanks for your input. I shoot outdoor smallbore prone in the United States.
I have considered that my vision is not necessarily the root cause of the issues. I am brave enough to understand that every shot I break is not perfect. But I have always been very good at identifying my mistakes and making accurate calls. Which is what is confusing me.
I have friends with Scatt Systems and potentially could borrow from them.
I am ordering new Decott safety glasses. I am thinking the plastic lens sport shooting glasses may cause distortion that I can't see.
I also ordered the MEC mirror to perfect alignment.
I'll report back on whether or not I find a solution.

Re: Fresnel Lenses, Cataract Surgery, and Sight Picture

Posted: Wed Jun 15, 2022 3:48 pm
by Richard144
I am far from an expert but have some of those same fliers when I think I have made a good shot. My analysis is simply that I am not the great shot I used to be. I am 77 years old, have had cataract surgery and have 20/20 vision now but also have an astingmatism. had trouble with target focus and so forth. Finally got a new prescription, bit the bullet, called Decot Hywyd, ordered a pair of their glasses and things got way way better. Focus is much better and it is fun again although not as good as I would like but like I said, at least now I own most of the fliers. I work on the fliers but I am also thrilled that I can still shoot some prone matches with iron sights.
Just keep working on it! And have fun.
Rick B.