Eyeglass prescriptions that correct for astigmatism have one “axis” or direction that can be specified. Real astigmatism can be vastly more complex than a single diopter adjustment in one direction. This makes many real astigmatism cases effectively uncorrectable.
To correct any possible astigmatism, it would require an infinite sum of series of correction terms at different angles and strengths.
But every glasses prescription I’ve ever gotten in the United States cuts that series off at one term. I’ve never seen nor heard of anyone getting custom lenses with two or more axes. It seems like it should be theoretically possible, but I also know very little about the process of lens grinding.
My understanding is that it’s just a limitation of the physical medium of a glass (or plastic) lens. There’s just only so much it can do - and only so many directions a lens can bend light at the same time before it enters your eye.
I have no complaints, despite the persistent starburst around lights at night. It’s not that big a deal. And I’ve never seen them any other way, after all.
My only other quibble is that my prescription makes everything look a little bit wider than it actually is. Either that, or my astigmatisms (one in each eye, and different from each other too!) make everything look more narrow than it really is? I’ve never really been sure….
Oh yeah. The starburst patterns absolutely are an unavoidable artifact of the axis correction in the lens. They are the result of diffraction doing Fourier optics on point light sources through an anisotropic (non-directionally symmetric) lens system.
As an example, here’s the James Webb Space Telescope, which has a hexagonal starburst pattern because its primary mirror is composed of hexagons (I believe the smaller horizontal spike is from the secondary mirror support strut):
I have astigmatism and have always had Starbursts despite the correct prescription. I’ve even had doctors double check to make sure I have the correct prescription after my complaints. So, either I’ve had several different doctors fucking with me for the last 30 some years, or humans are weird and not one size fits all for every situation
Sorry, but you’re wrong. I’m happy for you everything works but for lots of people they can either have clear eyesight or no issues with light sources in the dark.
It depends on your specific flavor of astigmatism. You’d have to get your eyeballs thoroughly checked out by a fancy eyeball doctor to know if yours can be corrected with glasses (or contacts) or not. Some can be, some can’t be, some can be partially corrected. At least that’s how the fancy eyeball doctors explained it to me.
If that’s your vision, y’all need glasses.
I have astigmatism. My glasses correct it. Led lights are fine.
Eyeglass prescriptions that correct for astigmatism have one “axis” or direction that can be specified. Real astigmatism can be vastly more complex than a single diopter adjustment in one direction. This makes many real astigmatism cases effectively uncorrectable.
Is it unfixable with lenses or only unfix able without lenses custom designed for your eye?
If that makes sense
To correct any possible astigmatism, it would require an infinite sum of series of correction terms at different angles and strengths.
But every glasses prescription I’ve ever gotten in the United States cuts that series off at one term. I’ve never seen nor heard of anyone getting custom lenses with two or more axes. It seems like it should be theoretically possible, but I also know very little about the process of lens grinding.
My understanding is that it’s just a limitation of the physical medium of a glass (or plastic) lens. There’s just only so much it can do - and only so many directions a lens can bend light at the same time before it enters your eye.
I have no complaints, despite the persistent starburst around lights at night. It’s not that big a deal. And I’ve never seen them any other way, after all.
My only other quibble is that my prescription makes everything look a little bit wider than it actually is. Either that, or my astigmatisms (one in each eye, and different from each other too!) make everything look more narrow than it really is? I’ve never really been sure….
Oh yeah. The starburst patterns absolutely are an unavoidable artifact of the axis correction in the lens. They are the result of diffraction doing Fourier optics on point light sources through an anisotropic (non-directionally symmetric) lens system.
As an example, here’s the James Webb Space Telescope, which has a hexagonal starburst pattern because its primary mirror is composed of hexagons (I believe the smaller horizontal spike is from the secondary mirror support strut):
We just need to fix out football shaped eyes instead of trying to correct it.
I have astigmatism and have always had Starbursts despite the correct prescription. I’ve even had doctors double check to make sure I have the correct prescription after my complaints. So, either I’ve had several different doctors fucking with me for the last 30 some years, or humans are weird and not one size fits all for every situation
Odd! I have no idea what that means.
Had a young friend checking out my new red-dot sight.
“Why’s it look like a star?”
“I have bad news…”
Irons gang rise up!
Etched reticules are also fine, and holographics are barbed wire but at least it stays contained.
Sorry, but you’re wrong. I’m happy for you everything works but for lots of people they can either have clear eyesight or no issues with light sources in the dark.
And damn, those glasses are expensive!
Do they make glasses that just fix astigmatism? I have great vision and don’t need glasses for sight. But I do have gnarly astigmatism.
They do. Get ready to feel drunk for a couple days if you get them.
Yes, and contacts too (for mild astigmatism)
It depends on your specific flavor of astigmatism. You’d have to get your eyeballs thoroughly checked out by a fancy eyeball doctor to know if yours can be corrected with glasses (or contacts) or not. Some can be, some can’t be, some can be partially corrected. At least that’s how the fancy eyeball doctors explained it to me.