Stand in front of military active radar should do the trick

Not a doctor, just an engineer, but retinas do not have much blood flow. So no "water cooling" like most other body parts. Also, once they're gone, they're gone for life iirc, so it is a tragic combination of poor heat transfer and being non replacable.

Common safety advice with high power microwave is to not look into cables or directional antennas just in case. Getting your hand burned is a lot better than your eyes cooked. Don't stick your hand into a microwave because I said that.

Also, don't take apart a microwave without knowing what you do. There are a few 1000s of Volt with enough Amps to (quite literally) cook you in there, plus a HV capacitor to smooth it out that could [1] be charged even after you unplugged it and could severely hurt you.

To quote the old warning: Not only will this kill you, it will also hurt the whole way.

[1]: which should have a discharge resistor, but do you want to gamble your life on it still working?

IIRC, this explains defense against RF crowd control and thus kinda also how its made.

https://inv.nadeko.net/Lg_aUOSLuRo