Something's been puzzling me lately involving astigmatism. As I understand it, astigmatism is the optical distortion that gets described as "seagulls" towards the periphery of the field and coma is radial smearing (like a certain "free" widefield ep

)
I've been noticing the seagull effect more or less in all my scopes with all my ep's from f4.9 to f10. But more to the point - the distortion moves around the field with eye movement. Is this to be expected or is it possibly an artifact from a lens implant?
It's more noticeable at low powers/f-ratios. I never got to do much observing before cataracts made an appearance so I don't have any benchmark observations and don't really know how bad it is.
Thanks in advance for any thoughts.