I am going to go against the grain here.
My riding teacher asked me to ride a rather elderly Arabian mare who had problems from her arthritis pain (I found a good supplement that worked). This mare would also become fixated whenever ANYTHING changed in the riding ring, a jump moved, the poles changed in color or position, an unusual shadow, etc… When she was fixated leg aids were either irritations or a reason to slip into a deeper fear to the point she would start to become terrified.
It FELT like she was searching for stuff to spook at, but I think her eyesight was changing (she was nearly 30 years old) and it was honest fear that she had no idea of how to deal with it.
In despair after several months I told my riding teacher I was going to count to 10 every time she planted her legs and grew roots when something changed. Get nearer to it? You must be kidding me, it could be DANGEROUS.
So I started counting to 10 every time she spooked at something (she spooked in place.) Some ride she would spook 10-12 times during my 30 minute ride. It took months, but gradually after she got a GOOD LONG look at the new thing, she relaxed.
After around 6 months this mare would spook in place, I would start counting to 10, and then after me saying ONE, TWO, and sometimes THREE she would start telling me that she had processed the scare and she was already ready to move forward.
After another month or so she stopped spooking when anything changed in the ring. She would LOOK at it at first, then sort of do a quiet snort, then bravely proceed onward obeying my aids. Then around another month would go by and she started IGNORING all the scary changes.
This is with me riding her 30 to 60 minutes a week (my 30 minute lesson and sometimes a 30 minute homework ride).
By stopping, letting her have a GOOD, IN DEPTH look at the scary things she finally learned to process the fear in her mind by herself. I think her eyesight had gotten worse several years earlier and no-one at all had allowed her to just stand and LOOK at the scary thing. She had to learn to use her eyes in a new way, and the only way she could do this was if I gave her the time to process everything.
She ended up being my preferred mount whenever my MS got worse. No matter how bad my balance and coordination got she would bravely plod around the ring, never putting a foot wrong and forgiving me all of my riding mistakes (which included occasional uncontrollable movements of my lower leg.)
She ended up forgiving me EVERYTHING so long as I did not hurt her extremely sensitive mouth.
And she ended up trusting me fully.
I really miss that mare.