We have little flashing red LED lights that you can clip on your saddle or breast collar.
They are mainly so other people notice you. We have to ride close to the road sometimes. I usually bring a little flashlight for me to see with. For the most part though I don't need it.
I used to know a guy that kept flashlights ducktaped to his saddle. He lived in Florida, and it is too hot to ride in the day in the summer there. I have thought about trying it, but I never have. I figure the lights will scare my horse. I try to get back before dark.
We ride at night most of the time - it is kind of a necessity here in the deep south. They sell headlamps in the camping section at Walmart. They are attached to a strap that fits nicely around your helmet (and you should especially be wearing a helmet when you night ride). Horses do see well in the dark, but humans don't so using a headlamp will help you see potential trail hazards such as a gopher hole or a cactus that even your horse's night vision won't register. The lamps usually have 3-4 settings on them. We then put red blinkie lights on the back of our helmets so that we can be seen from behind as well. That is particulary helpful if you have to ride along side of a road for any distance. Just remember that even a well trained and seasoned horse will be a little mory jumpy at night. I'll be interested in hearing if anyone gives it a try!
We ended up out riding too late one time where we had to ride on a gravel road in the dark. A car came from the other direction with it's bright lights on and swerved at us. We had to run for the ditch so we didn't get hit. Afterward, we went and bought some cheap flashlights that also glowed and flashed in color.
I've heard to not use a bright light at night because it hinders the horses sight. If you feel queasy, you should hang a light under the horse that illuminates the ground but won't interfere with the horse's sight.
I have thought about getting one of those led cap lights to try out. There are those blinking lights that joggers use which might work too.
Get one of those LED head lamps, Put it in the red or blue light mode so you can see branches before they hit you in the face and then ride. The horses can see well enough that they don't need any light.
This is what we do, too. Trust your horse to take care of you and just have a low light for those branches. Full moon nights are great...you don't need anything and the 'mood' is wonderful.
Maybe this fall or winter we can take a full moon ride in the woods at Tyrrell Park. That would be fun!
Horses do have a great sense of direction. This spring we went riding in McKinney Roughs and had rode twice in the heat for a little over 16 miles. Biscuit was getting tired and decided trotting wasn't going to cut it for him any more that day. The other two horses took a left hand turn at a trail that ended on another. Instead of following them, Biscuit turned right! Then a little off center of the trail was a sign telling me they went the wrong way! Biscuit knew the trailer was down the right side not the left! LOL Biscuit is a smart boy who knows his way around so if I ever get lost in the dark I will let Biscuit have his head - he will get me back to the trailer!
Like some people have said, using red lights will not reduce your night vision by much. I once spent the night at an observatory and they had red lights indoors so that when you went back outside to stargaze it wouldn't mess up your night vision. It also takes about half an hour for your eyes to fully adjust to the dark, all of which has to be restarted if you look into bright (white) light.
Horses also tend to have a longer adjustment time to dark light, their eyes are mainly for daylight and dusk/dawn use. If you suddenly use bright lights your horse will take longer than you to get back the "night vision." that said, they still do see better than us poor humans in the dark. I think adding red lights to the breastplate or maybe your helmate is a great idea for night trail-rides.
Moonlight is also awesome... has anyone noticed that your shadow is MUCH sharper in the moonlight than in the sunlight? It's really cool!
I like having breastcollar lights to illuminate the ground and a red light on my helmet to keep me from being attacked by low-hanging limbs, etc. the lights being under her head don't seem to affect dreams' night vision at all but they give me an idea of the terrain, so I can follow her movement a lot better.
I just use electricians tape to attach the lights, as it stays put (even when wet), but cuts off easily.
At a barn I used to ride at, I'd often ride in the arena at night (but not trails as getting to them required going down the road and I didn't fancy getting run over). There were lights but you had to plug money into a machine to make them work, so I just rode in the dark because I'm cheap. The horse knew exactly where the rail was anyway and there was usually enough light pollution from the city that you could see pretty well. We'd done night rides on trails with cliffs in Colorado and trails without cliffs elsewhere. Horse has never put a foot wrong. Had the following exchange with the barn owner though when she caught me out riding in the dark:
BO: The rules say you have to ride with the arena lights on.
BO: Because it's dangerous.
Me: Why is it dangerous? We can see fine.
BO: The horse will spook at more things in the dark.
Me: She's not spooking. See, she's as relaxed as she always is.
BO: She won't be able to see the fence or the edge of the arena and might crash into it.
Me: *blank stare of 'you really did just say that?'*
Some other thoughts: There are lots of different Mountain Biking lights that work very well. Night Sun has one of the strongest, with the battery in a "water bottle". The Night Sun also has several settings for light intensity to save battery. When I did ultra-distance road riding we used a cheaper bike light with lantern batteries wired so they would last all night.
Some thoughts about head mounted lights: When biking I always preferred both a head lamp and a static mount. The problem with head lamps is if you look away you lose focus on what is in front because the light moves. Also, there are times you need to be aware of what is right under you, while you are looking ahead. Head lamps also throw some pretty heavy shadows that my mare thinks are scary.
Trail Light: LED Light, mounts on Breast Collar: "Super Nova" LED casts 180 degrees of light, for no shadows to spook the horse. Velcro attaches to breast collar, universal fit. 4650Universal fit with switch, switch on w/o dismounting, attaches easily. 180 Degree light coverage. $60