Fresnel Lenses, Cataract Surgery, and Sight Picture
Posted: Fri Jun 10, 2022 3:50 pm
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?)
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?)