How Do Horned Lizards Shoot Out Blood From Their Eyes?

Complements of the season people!

Description Of The Creature.
 Horned lizards also called Horny Toads are ant-eating,thorny(spiny) looking creatures. The genus is thought to have split from an ancestor shared with the sand lizards (Uma, Callisaurus, Cophosaurus, and Holbrookia) during the late Oligocene-early Miocene (23- 30 mya). Presently, there are 14 -18 known species of the horned lizards that live in dry desert areas(from Guatemala and Mexico up through the Western United States and even into Southern Canada). The most fascinating thing about this lizard is their ability to shoot out blood almost 5 feet from their eyes.
"How do they do it?", You may ask. And "Why do they do it".

Defense.
The action-Auto Haemorrhaging, is performed by horned lizards in order to defend themselves against predators(wolves, coyotes, bobcats, hawks, snakes,etc).
Well, this doesn't mean that is the only action they possess for defense. In fact, when it comes to camouflage, horned lizards are as good at it as any other reptile.
First up, they try to blend in with the desert area, stay still to avoid being spotted by predators. The bad news is; this doesn't often work so they try another measure when they have been detected. As smart as they are, they try to run with their short legs and flat bodies which makes it very easy for predators to catch them because, damn, they are slow.
When they are caught, they try the next step which is puffing themselves to become as large as they can actually be. Why do they do this? Its because this makes it difficult for some predators to eat them whole so they might just turn around and go. Smart isn't it?
But some predators still are able to eat them whole so they try one last measure they have tight up their sleeves ~ Auto-Haemorrhaging.
They shoot blood from their eyes which terrifies their predators making them almost peeing in their pants, that's if they've got one. So they flee and leave the horned lizards unharmed. But the question is...
How Can A  Wise Little Fella Shoot Blood From Its Eyes?
Easy! Well for them, humans can't.
Horned lizards can contract muscles around their eyes, on doing this, blood flow is cut off back to the heart. Shortly, the Ocular Sinuses becomes filled with blood.
As the muscles continue to contract, the sinus membrane is compressed or pressurised, releasing blood that can shoot out from their eyes as the thin sinus membrane ruptures. This allows blood to be shot up to 4 and a half feet from the eye enough to frighten even humans, lucky for us, they dont shoot at us.
Horned lizards apart from the purpose of defense can apply this measure to wash out dirt particles from their eyes performing the job of tears.
 They can repeat the process again and again within a short period of time depending on how long the predator attacks or how hungry it is.
To know why horned lizards dont shoot at us...

Stay tuned.

References:
• Wonderpolis.
• "Horned Lizards by" Eric R. Pianka and Wendy L. Hodges.