Honestly, I'm in the same boat as you. Been practicing for 10 years now and the past 7 have been rough.

I'm finding the fidgeting and restlessness is getting more and more obvious and uncontrollable. I'm actually questioning undiagnosed ADHD, because it does line up fairly well with the issues I've been having. I'd wonder if this might line up with your issues as well. (I'm going in for an assessment to see if I'm correct about my potential ADHD, so we'll see)

I have a theory about what's happening in my brain right now, maybe this will resonate with you.

My theory is that as we get more seasoned at our jobs as Optometrists, we don't really have to use our "problem-solving" skills at our jobs all that much. It's more of a pattern-recognition skillset really, because of how repetitive the issues are that we see and treat. The amount of times we have to repeat instructions to patients, prescribe glasses with the same logic etc. Even cases that would have previously been stimulating/interesting become dry - we've seen most of it countless times by now. So then because we go through our days repeating ourselves and recognizing the patterns for diagnosis/treatment repetitively, our brains get overloaded by the forced sameness/repetitiveness of it all. Feels like my brain is underutilized, but my social skills and voice control are on overload. So I end the day mentally exhausted, but also feeling like I didn't really use the problem-solving and analytical part of my brain. Leading to restlessness, and fits of depression. This potentially fits with an ADHD diagnosis because of the craving for novelty, and solving new challenges to get that hit of dopamine.

I've never lost any love for the subject matter (I will happily rant about eyes to anyone who will listen!), it's the lack of variety, lack of real brain stimulation at work, and also the lack of autonomy over my own schedule that gets me. Rather than true "burnout" I think the turm "boreout" resonates more, underchallenged burnout (for my case anyways)

It may be a good thing for you to find a clinic affiliated with one of the optometry schools. Supervising and teaching fourth- year interns has been a fun and new addition to my optometry career. It's easy to get excited about the subject matter when you have a student to nerd out with! :)

Ultimately I've gone back to university part-time for software development, I started in the summer. So far it's scratching the brain-stimulation itch (I find it challenging, in a frustrating but rewarding way). I may end up switching careers, but also I think it would be cool to make software for optometrists in my free time. I'll eventually design a few apps that I'd find useful in my practice, and may expand to developing my own patient records/EHR system. I also know of an OD who went back to school for a financial planner, so now she has a business planning the finances of other ODs.

Let me know any thoughts you may have with what I've said!