Greetings Brothers (and Sisters),
I thought it would be interesting to discuss things you have done or can do to the minis to fit the lore of bright lights hurt Night Lord eyes. In the Past I have done a simple plastic card metal coverings or justified you can make different coloured flames using different chemicals but I wanted more character on some minis.
So here is my simple suggestion, inverting a Primaris Inceptors gun shield on a Melta gun gives a mini Breacher like quality. It leaves a gun sight or aiming the weapon but would primarily block out most of the light produced by the weapon. (Orginally I was looking at the Inceptors wielding helmet before deciding it didn't suit the Legion look).