Looks like the eye of a big billfish to me, namely a sword. Size and the grey color of the surrounding skin are good matches. Color, musculature and dimensional stability argue against ceph, I'm afraid.
On the other hand, it could mean that Sauron retired to Florida.
I agree - it looks like the eyecup has cartilaginous support, so not floppy enough to be cephy. The lens size seems to large compared with the total volume of the eye, too. Cephs have rather small lenses, comparatively speaking.
A quick examination of the retina (if it's at all intact) would tell for sure. On gross structure, I don't think it's a cephalopod.