[Someone]

https://www.merriam-webster.com/dictionary/fix:

to direct one's attention or efforts : FOCUS

also : DECIDE, SETTLE —usually used with on

had fixed on the first Saturday in June

All eyes fixed on her as she entered the room.

[marky1991]

Yes, exactly: 'Fixed ON', the eyes are "fixed", it's completely different grammar.

[Someone]

The example uses on, but the entry says usually used with on. That leaves open images that do not use on.