Across the room? Poised to throw the knife at you or just holding it in their hand?
A lot depends on your state laws.
Bright flash light and pepper spray if you chose non lethal, if your life is in danger and you live in a state like mine that has castle doctrine and stand your ground laws you can defend your home with deadly force if you are in fear for your life.
If you live in California or one of the socialist police states then gently throw your wallet at the burglar from the fetal position while whimpering in the corner, but don't throw your wallet too hard or you could get charged and/or sued.
If you are crazy enough to even consider a dazzler for self defense then know your state laws and be prepared to spend lots of time and money in court.
p.s. Pepper spray works 99% of the time, it really sucks to get a face full of that stuff. Can't even see it coming with a bright flashlight in your face.
Real tasers work most of the time, but those million volt toys they sell on flebay and at gun shows will only piss someone off, we used to zap each other for fun with em. If you get a really good one you just might get your attackers adrenaline flowing before he crams it up your backside.
