Worried about B

This morning when I went to bring B in he spooked and ran through the electric fence. (He is fine. Just jumpy)

He is partially sighted but I'm concerned now that it has progressed and he is now potentially almost blind. I've been reading a bit online and have read about someone who thought there horse had only distance vision. This sounds a lot like B. He will shout as I approach the field (if he is looking out for me) and look all happy to see me and keen to come in but as soon as I get closer he looks worried and backs away. I have to stretch out my hand for him to sniff before I can catch him. (I always talk to him all the time also)
In his stable he is fine. Sometimes he gets a fright if he is rubbing against me and accidentally knocks his head off the wall or my shoulder, like he didn't know it was there.

My main worry is guy fawkes night. He hates fireworks. I can't leave him in as he panics and throws himself against the walls. But I'm now worried he will run through fencing in the field. My initial thought was to leave everything as it is as he should know where the fence boundaries are (where he ran through this morning used to be a gate way until a month ago when I started to move the fence to give Peds a wee bit more grass) or I can remove all the fencing Appart from the boundary fence so they have the whole field for the night (waaaay too much grass for Peds)

I have Magnatude, which I give to Peds as a calmer, so B could get this also in the week before but I'm not sure it would really help in this situation. (There is a big organised fireworks display at the back of their field in a public park. They are separated by a small field and a river then there is the park so it is very close. I always stay up and keep any eye on them while it's going on just incase)

Think I'm going to have to phone the vet today and discuss what to do. Aging sucks!

I don't want to give him a sedative as he has a weak back end and would fall over very easily. I'll look into the chamomile flowers. Going to phone the vets at lunch time.

@Jessey he is always pretty stressed by them. He's much better out, last year he just jogged back and forth behind Peds and Cher who were huddled together at the top of the field (after having a gallop around at the first few fireworks ) This year it's just B and Peds in their field so not sure how they will be. Thankfully the horses right next to them don't tend to bother about them so I imagine Peds will stand at the fence next to J and hopefully B will just jog about behind them.

I've ordered global herbs fireworx. Both the powder and the liquid. I was reading that so.some people feed the powder over the firework period and then the liquid on days that there are going to be big displays close by.

I read up about the chamomile and it said it can be toxic long term and cause liver failure. B already has liver disease so I don't want to put a further strain on that.

@Jessey I don't think he's compleatly blind as he manages to stick to Peds most of the time in the field and finds water fine and no problems with feed in his stable (they are always in the same place but he doesn't look like he's snuffling about for them. Just head straight in!) I did get a good look at his eyes when I turned out this morning. It was dark and the light at the gate was shining into his eye. On the left side his whole pupil is a milky haze and most of the right pupil is too. I'm guessing that's his catteracts grown. He was spooky going into the field. Wouldn't go to the gate but it's pitch black round there until I get the light on so tomorrow morning I'm going to nip to the field and switch the light on while there having breakkie and see if that's makes things easier for him. He's definitely worse than last year tho. And I won't deny I had a wee weep into his forelock this morning after I'd turned him out!