What would cause an eye to look like there was blood in it. Like bloodshot but worse. with no injury before?

The person that this happen to is a male 67 years old, and drove almost 9hours the previous night. No symptoms other than the blood in the eye. Almost like someone popped them in the eye.

pinkeye, just not having enough rest will make you eyes red,

my mother suffers from this. its not painful, it looks like a blood clot. It will probably go away in two-three days. her doctor says hers are caused when she bends over the pressure causes the buising which looks like a blood clot.

probably strained too much & blew a blood vessel.
Stay well hydrated. Even sleep with a humidifier, if possible.
take vitamin A & vitamin B complex
use cold compresses to soothe it.
avoid eye drops
If a few days pass without improvement, go see the Dr.

it sounds like a popped blood vessel iv had it happen before...its gross but it will go away....if your concerned call your doctor

It is probably a broken blood vessel. They are usually harmless although they look awful. It will gradually disappear over several days.

stress can cause problems like that, sounds like eye strain, for 9 hours......

There are a lot of things that could cause this. Probably the most common and the most likely one is just a broken blood vessel. If he doesn't have any associated pain or other abnormal sensations, that's probably what it is. (They resolve in a week or two, depending on how big the vessel is.) If he wants to be on the safe side, a quick visit to his eye doctor wouldn't hurt.