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):
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.