When a horse is blinded by fear, you'll know, because your heart will be in your throat, your stomach will be in knots, and you'll be sitting on the edge of your seat like you're watching a horror movie about to take a turn for the worse, metaphorically speaking.
When a horse is blinded by fear, they can do crazy, dangerous things. I've seen horses pulling a cart or wagon, run right through a crowd of people sending folks to the hospital and even into the grave. I've seen horses smash right into a wall, then fly over backward to the ground because their momentum and speed left no other options. I've seen horses get tied up in fences and destroy their own bodies because when the prey animal instinct kicks in at full throttle, there is literally no clear eyesight in the horse. That's why we call it blinded by fear.
Humans do it too. I watched my brother skin up his knees and run head first into a tree because somebody thought it would be funny to toss a small garter snake in his direction on the golf course. When the brain shuts down, so does most of the visual cortex. It's not that you can't see at all. It's that all you can see is the threat and your only escape is the tactile sensations you feel as you bounce off the walls.
What do you do when a horse is so scared they literally gallop right into danger? To be honest, the answer isn't so cut and dry, but basically, what I do, is try to stop them from injuring anyone or themselves. If I can't stop them, I just try to warn everybody around at the top of my lungs and begin cleaning up after the tornado. When you've got a one-thousand-pound plus animal running at full tilt toward potential injury or death, all you can do at times is throw up your hands and hope he sees what he needs to see before he kills himself. I try to pretend I'm calm and keep a calm demeanor so as to not exaggerate his motions. Some people run up to the horse while it's struggling, causing even more harm because the horse is so blinded that everything looks scary, even you. I try to remain calm, unless the only option is to run toward and try to stop it. Regardless, I may present myself as calm but inside, I'm all churned up.
One reason I try to look calm is to invite others to be calm around me. Last month a rider in a clinic got too close to another rider and her young horse exploded. As her horse bucked and careened around the arena, we all noticed she was going to fall from her horse, and instinctively, we all knew if we raced over to the horse to try and catch her, we'd fuel the fire in the horses feet, causing a spin or something dramatic and sudden, leaving even more potential for injury. So we stood, on guard, waiting for the tornado to pass then when she landed we quickly came to her aid.
Like most things that really go wrong, the solution is in the prevention. If you're quick enough to notice the horses face going sour, and the tension in the muscles, you can stop the train before it goes down the hill. So many of my classes are about prevention. You need to learn to read the horse and read the horses around your horse. Knowing what could happen next, often solves a great many problems. However, shit happens. When it happens, if you can't control it or prevent it, the key is to try and be a useful participant in the clean up after the storm.
If you can, try to prevent even more from happening too. Knowing that horses loose their ability to see clearly helps because that means any visual cues you send need to be grand. For instance, if you want to stop a blind horse from running into a crowd, it would help if the crowd all waved their hands frantically. I use a flag day to day with horses. When a horse is triggered into blind fear I attempt to wave that flag from the right position in the arena to stop the horse from jumping a fence or crashing through a gate. Sometimes it helps. Staying calm but being firm can help you stop a running horse without fueling his fire.
However, like I said before, shit still happens. The best thing you can do is clean up the mess and go to work on your mental journal. Try to lock in why the horse did what he did. What did the horse look like, just before he did what he did? Don't get caught up thinking you should avoid things, instead think about how you could prepare for things. For instance, if a bicycle scares your horse off the trail, don't get caught up thinking you should avoid bicycles from here on out. Think about how you can prepare your horse to handle bicycles. Remember to think back and notice the electrical tension rising in the horse. People often say it came out of the blue. They say there were no signs leading up to the explosion. Let me tell you from experience. There are always signs. Use your memory to uncover them. They may be subtle things, like your horse holding his breath. They may be sudden things like an electrical charge in your horse from a noise or flash. Any of those things can be worked on, prepared for, helped. You can teach a horse not to go crazy, to stay grounded in spite of that electrical surge.
In conclusion, if it happens to you, hang in there, you're not alone. If you can learn the right things from those scary moments, you're on the track to mastery. If you have a story to tell, one that you and your horse survived by the skin of your teeth, you have joined the ranks of horseman and horsewomen around the world. We all have harrowing stories to tell. Those of us who are still here, still "standing in the arena," just like Teddy Roosevelt said, are the ones who know deeper truths and have earned stronger hearts and minds.