@Otto - You have a lot going on in your neck that, in my opinion, was left mentioned by the radiologist. I’d say this part, in particular, is incorrect:
I’ve annotated your images & will comment below the annotated image regarding what I see. Remember I’m not a doctor & anything I comment on can’t be considered diagnostic but can be discussed w/ any doctor you see for a true medical opinion.
I fully agree with all that @Jules said especially about how thick your styloids are. I’m not sure I’ve seen any as thick as yours & as she noted, the thickness alone can cause the styloids to be closer to the transverse processes (TPs) of C1 thus creating a higher risk of vascular compression especially of the IJVs at the level of C1. I also agree that your cervical spine is very straight & working carefully & gently at restoring the lordotic curve could help reduce your symptoms to some degree, but ultimately, it will likely be surgery to remove your styloids as close to skull base as possible that will make the biggest difference. C1 may also need to be shaved to give more room to your IJVs.
In the upper left image, the styloid appears to possibly be touching the internal carotid artery (ICA) whereas the greater horn of the hyoid looks like it may be up against the external carotid artery though, in both, cases it may just be the angle of the image that makes it look like that. If either the styloid or hyoid greater horn are in contact w/ any part of your carotid arteries, whether or not they’re causing compression, they can cause irritation to it which can cause some of the symptoms you’re having in your head & eyes. In that left top image, your IJV looks ok to me, however in the lower portion w/ the axial slices (the 2 middle images), both IJVs appear to be suffering some compression in part due to your styloids & in part due to C1. Because the styloids are so thick, if they were cut back above the TP of C1 on each side, the IJVs might decompress w/o a surgeon needing to touch the TPs of C1.
In the second picture at the top, it appears you may have a carotid “fenestration” which is occurring as the ECA attaches to the ICA (marked w/ an arrow) rather than remaining a separate vessel. I don’t know if that would be significant in causing symptoms but it’s worth noting. I can’t see your hyoid on that side so can’t comment on the position of the greater horn.
Your IJV on that side is quite small in circumference compared to the other side. This is not uncommon. Many people have a more dominant, larger IJV (though sometimes the smaller one is dominant) T.hat vessel could potentially enlarge if your styloid was removed near the skull base on that side.
In the axial slices, the spots that I’ve marked “IJV” pretty clearly show compression of the veins as they are ovals vs being round. In the right hand middle picture, the left IJV, in particular, is pretty flat. I suspect the right one might also be though it’s less so in that particular picture.
Please let me know if you have any questions. I know my descriptions of what I see may be a little confusing.